---
_id: '6430'
abstract:
- lang: eng
text: "A proxy re-encryption (PRE) scheme is a public-key encryption scheme that
allows the holder of a key pk to derive a re-encryption key for any other key
\U0001D45D\U0001D458′. This re-encryption key lets anyone transform ciphertexts
under pk into ciphertexts under \U0001D45D\U0001D458′ without having to know the
underlying message, while transformations from \U0001D45D\U0001D458′ to pk should
not be possible (unidirectional). Security is defined in a multi-user setting
against an adversary that gets the users’ public keys and can ask for re-encryption
keys and can corrupt users by requesting their secret keys. Any ciphertext that
the adversary cannot trivially decrypt given the obtained secret and re-encryption
keys should be secure.\r\n\r\nAll existing security proofs for PRE only show selective
security, where the adversary must first declare the users it wants to corrupt.
This can be lifted to more meaningful adaptive security by guessing the set of
corrupted users among the n users, which loses a factor exponential in Open image
in new window , rendering the result meaningless already for moderate Open image
in new window .\r\n\r\nJafargholi et al. (CRYPTO’17) proposed a framework that
in some cases allows to give adaptive security proofs for schemes which were previously
only known to be selectively secure, while avoiding the exponential loss that
results from guessing the adaptive choices made by an adversary. We apply their
framework to PREs that satisfy some natural additional properties. Concretely,
we give a more fine-grained reduction for several unidirectional PREs, proving
adaptive security at a much smaller loss. The loss depends on the graph of users
whose edges represent the re-encryption keys queried by the adversary. For trees
and chains the loss is quasi-polynomial in the size and for general graphs it
is exponential in their depth and indegree (instead of their size as for previous
reductions). Fortunately, trees and low-depth graphs cover many, if not most,
interesting applications.\r\n\r\nOur results apply e.g. to the bilinear-map based
PRE schemes by Ateniese et al. (NDSS’05 and CT-RSA’09), Gentry’s FHE-based scheme
(STOC’09) and the LWE-based scheme by Chandran et al. (PKC’14)."
alternative_title:
- LNCS
article_processing_charge: No
author:
- first_name: Georg
full_name: Fuchsbauer, Georg
id: 46B4C3EE-F248-11E8-B48F-1D18A9856A87
last_name: Fuchsbauer
- first_name: Chethan
full_name: Kamath Hosdurg, Chethan
id: 4BD3F30E-F248-11E8-B48F-1D18A9856A87
last_name: Kamath Hosdurg
- first_name: Karen
full_name: Klein, Karen
id: 3E83A2F8-F248-11E8-B48F-1D18A9856A87
last_name: Klein
- first_name: Krzysztof Z
full_name: Pietrzak, Krzysztof Z
id: 3E04A7AA-F248-11E8-B48F-1D18A9856A87
last_name: Pietrzak
orcid: 0000-0002-9139-1654
citation:
ama: 'Fuchsbauer G, Kamath Hosdurg C, Klein K, Pietrzak KZ. Adaptively secure proxy
re-encryption. In: Vol 11443. Springer Nature; 2019:317-346. doi:10.1007/978-3-030-17259-6_11'
apa: 'Fuchsbauer, G., Kamath Hosdurg, C., Klein, K., & Pietrzak, K. Z. (2019).
Adaptively secure proxy re-encryption (Vol. 11443, pp. 317–346). Presented at
the PKC: Public-Key Cryptograhy, Beijing, China: Springer Nature. https://doi.org/10.1007/978-3-030-17259-6_11'
chicago: Fuchsbauer, Georg, Chethan Kamath Hosdurg, Karen Klein, and Krzysztof Z
Pietrzak. “Adaptively Secure Proxy Re-Encryption,” 11443:317–46. Springer Nature,
2019. https://doi.org/10.1007/978-3-030-17259-6_11.
ieee: 'G. Fuchsbauer, C. Kamath Hosdurg, K. Klein, and K. Z. Pietrzak, “Adaptively
secure proxy re-encryption,” presented at the PKC: Public-Key Cryptograhy, Beijing,
China, 2019, vol. 11443, pp. 317–346.'
ista: 'Fuchsbauer G, Kamath Hosdurg C, Klein K, Pietrzak KZ. 2019. Adaptively secure
proxy re-encryption. PKC: Public-Key Cryptograhy, LNCS, vol. 11443, 317–346.'
mla: Fuchsbauer, Georg, et al. Adaptively Secure Proxy Re-Encryption. Vol.
11443, Springer Nature, 2019, pp. 317–46, doi:10.1007/978-3-030-17259-6_11.
short: G. Fuchsbauer, C. Kamath Hosdurg, K. Klein, K.Z. Pietrzak, in:, Springer
Nature, 2019, pp. 317–346.
conference:
end_date: 2019-04-17
location: Beijing, China
name: 'PKC: Public-Key Cryptograhy'
start_date: 2019-04-14
date_created: 2019-05-13T08:13:46Z
date_published: 2019-04-06T00:00:00Z
date_updated: 2023-09-08T11:33:20Z
day: '06'
department:
- _id: KrPi
doi: 10.1007/978-3-030-17259-6_11
ec_funded: 1
intvolume: ' 11443'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://eprint.iacr.org/2018/426
month: '04'
oa: 1
oa_version: Preprint
page: 317-346
project:
- _id: 258AA5B2-B435-11E9-9278-68D0E5697425
call_identifier: H2020
grant_number: '682815'
name: Teaching Old Crypto New Tricks
publication_identifier:
eissn:
- '16113349'
isbn:
- '9783030172589'
issn:
- '03029743'
publication_status: published
publisher: Springer Nature
quality_controlled: '1'
related_material:
record:
- id: '10035'
relation: dissertation_contains
status: public
scopus_import: '1'
status: public
title: Adaptively secure proxy re-encryption
type: conference
user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1
volume: 11443
year: '2019'
...
---
_id: '6528'
abstract:
- lang: eng
text: We construct a verifiable delay function (VDF) by showing how the Rivest-Shamir-Wagner
time-lock puzzle can be made publicly verifiable. Concretely, we give a statistically
sound public-coin protocol to prove that a tuple (N,x,T,y) satisfies y=x2T (mod
N) where the prover doesn’t know the factorization of N and its running time is
dominated by solving the puzzle, that is, compute x2T, which is conjectured to
require T sequential squarings. To get a VDF we make this protocol non-interactive
using the Fiat-Shamir heuristic.The motivation for this work comes from the Chia
blockchain design, which uses a VDF as akey ingredient. For typical parameters
(T≤2 40, N= 2048), our proofs are of size around 10K B, verification cost around
three RSA exponentiations and computing the proof is 8000 times faster than solving
the puzzle even without any parallelism.
alternative_title:
- LIPIcs
article_number: '60'
article_processing_charge: No
author:
- first_name: Krzysztof Z
full_name: Pietrzak, Krzysztof Z
id: 3E04A7AA-F248-11E8-B48F-1D18A9856A87
last_name: Pietrzak
orcid: 0000-0002-9139-1654
citation:
ama: 'Pietrzak KZ. Simple verifiable delay functions. In: 10th Innovations in
Theoretical Computer Science Conference. Vol 124. Schloss Dagstuhl - Leibniz-Zentrum
für Informatik; 2019. doi:10.4230/LIPICS.ITCS.2019.60'
apa: 'Pietrzak, K. Z. (2019). Simple verifiable delay functions. In 10th Innovations
in Theoretical Computer Science Conference (Vol. 124). San Diego, CA, United
States: Schloss Dagstuhl - Leibniz-Zentrum für Informatik. https://doi.org/10.4230/LIPICS.ITCS.2019.60'
chicago: Pietrzak, Krzysztof Z. “Simple Verifiable Delay Functions.” In 10th
Innovations in Theoretical Computer Science Conference, Vol. 124. Schloss
Dagstuhl - Leibniz-Zentrum für Informatik, 2019. https://doi.org/10.4230/LIPICS.ITCS.2019.60.
ieee: K. Z. Pietrzak, “Simple verifiable delay functions,” in 10th Innovations
in Theoretical Computer Science Conference, San Diego, CA, United States,
2019, vol. 124.
ista: 'Pietrzak KZ. 2019. Simple verifiable delay functions. 10th Innovations in
Theoretical Computer Science Conference. ITCS 2019: Innovations in Theoretical
Computer Science, LIPIcs, vol. 124, 60.'
mla: Pietrzak, Krzysztof Z. “Simple Verifiable Delay Functions.” 10th Innovations
in Theoretical Computer Science Conference, vol. 124, 60, Schloss Dagstuhl
- Leibniz-Zentrum für Informatik, 2019, doi:10.4230/LIPICS.ITCS.2019.60.
short: K.Z. Pietrzak, in:, 10th Innovations in Theoretical Computer Science Conference,
Schloss Dagstuhl - Leibniz-Zentrum für Informatik, 2019.
conference:
end_date: 2019-01-12
location: San Diego, CA, United States
name: 'ITCS 2019: Innovations in Theoretical Computer Science'
start_date: 2019-01-10
date_created: 2019-06-06T14:12:36Z
date_published: 2019-01-10T00:00:00Z
date_updated: 2021-01-12T08:07:53Z
day: '10'
ddc:
- '000'
department:
- _id: KrPi
doi: 10.4230/LIPICS.ITCS.2019.60
ec_funded: 1
file:
- access_level: open_access
checksum: f0ae1bb161431d9db3dea5ace082bfb5
content_type: application/pdf
creator: dernst
date_created: 2019-06-06T14:22:04Z
date_updated: 2020-07-14T12:47:33Z
file_id: '6529'
file_name: 2019_LIPIcs_Pietrzak.pdf
file_size: 558770
relation: main_file
file_date_updated: 2020-07-14T12:47:33Z
has_accepted_license: '1'
intvolume: ' 124'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://eprint.iacr.org/2018/627
month: '01'
oa: 1
oa_version: Published Version
project:
- _id: 258AA5B2-B435-11E9-9278-68D0E5697425
call_identifier: H2020
grant_number: '682815'
name: Teaching Old Crypto New Tricks
publication: 10th Innovations in Theoretical Computer Science Conference
publication_identifier:
isbn:
- 978-3-95977-095-8
issn:
- 1868-8969
publication_status: published
publisher: Schloss Dagstuhl - Leibniz-Zentrum für Informatik
quality_controlled: '1'
scopus_import: 1
status: public
title: Simple verifiable delay functions
tmp:
image: /images/cc_by.png
legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
short: CC BY (4.0)
type: conference
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 124
year: '2019'
...
---
_id: '298'
abstract:
- lang: eng
text: "Memory-hard functions (MHF) are functions whose evaluation cost is dominated
by memory cost. MHFs are egalitarian, in the sense that evaluating them on dedicated
hardware (like FPGAs or ASICs) is not much cheaper than on off-the-shelf hardware
(like x86 CPUs). MHFs have interesting cryptographic applications, most notably
to password hashing and securing blockchains.\r\n\r\nAlwen and Serbinenko [STOC’15]
define the cumulative memory complexity (cmc) of a function as the sum (over all
time-steps) of the amount of memory required to compute the function. They advocate
that a good MHF must have high cmc. Unlike previous notions, cmc takes into account
that dedicated hardware might exploit amortization and parallelism. Still, cmc
has been critizised as insufficient, as it fails to capture possible time-memory
trade-offs; as memory cost doesn’t scale linearly, functions with the same cmc
could still have very different actual hardware cost.\r\n\r\nIn this work we address
this problem, and introduce the notion of sustained-memory complexity, which requires
that any algorithm evaluating the function must use a large amount of memory for
many steps. We construct functions (in the parallel random oracle model) whose
sustained-memory complexity is almost optimal: our function can be evaluated using
n steps and O(n/log(n)) memory, in each step making one query to the (fixed-input
length) random oracle, while any algorithm that can make arbitrary many parallel
queries to the random oracle, still needs Ω(n/log(n)) memory for Ω(n) steps.\r\n\r\nAs
has been done for various notions (including cmc) before, we reduce the task of
constructing an MHFs with high sustained-memory complexity to proving pebbling
lower bounds on DAGs. Our main technical contribution is the construction is a
family of DAGs on n nodes with constant indegree with high “sustained-space complexity”,
meaning that any parallel black-pebbling strategy requires Ω(n/log(n)) pebbles
for at least Ω(n) steps.\r\n\r\nAlong the way we construct a family of maximally
“depth-robust” DAGs with maximum indegree O(logn) , improving upon the construction
of Mahmoody et al. [ITCS’13] which had maximum indegree O(log2n⋅"
alternative_title:
- LNCS
article_processing_charge: No
arxiv: 1
author:
- first_name: Joel F
full_name: Alwen, Joel F
id: 2A8DFA8C-F248-11E8-B48F-1D18A9856A87
last_name: Alwen
- first_name: Jeremiah
full_name: Blocki, Jeremiah
last_name: Blocki
- first_name: Krzysztof Z
full_name: Pietrzak, Krzysztof Z
id: 3E04A7AA-F248-11E8-B48F-1D18A9856A87
last_name: Pietrzak
orcid: 0000-0002-9139-1654
citation:
ama: 'Alwen JF, Blocki J, Pietrzak KZ. Sustained space complexity. In: Vol 10821.
Springer; 2018:99-130. doi:10.1007/978-3-319-78375-8_4'
apa: 'Alwen, J. F., Blocki, J., & Pietrzak, K. Z. (2018). Sustained space complexity
(Vol. 10821, pp. 99–130). Presented at the Eurocrypt 2018: Advances in Cryptology,
Tel Aviv, Israel: Springer. https://doi.org/10.1007/978-3-319-78375-8_4'
chicago: Alwen, Joel F, Jeremiah Blocki, and Krzysztof Z Pietrzak. “Sustained Space
Complexity,” 10821:99–130. Springer, 2018. https://doi.org/10.1007/978-3-319-78375-8_4.
ieee: 'J. F. Alwen, J. Blocki, and K. Z. Pietrzak, “Sustained space complexity,”
presented at the Eurocrypt 2018: Advances in Cryptology, Tel Aviv, Israel, 2018,
vol. 10821, pp. 99–130.'
ista: 'Alwen JF, Blocki J, Pietrzak KZ. 2018. Sustained space complexity. Eurocrypt
2018: Advances in Cryptology, LNCS, vol. 10821, 99–130.'
mla: Alwen, Joel F., et al. Sustained Space Complexity. Vol. 10821, Springer,
2018, pp. 99–130, doi:10.1007/978-3-319-78375-8_4.
short: J.F. Alwen, J. Blocki, K.Z. Pietrzak, in:, Springer, 2018, pp. 99–130.
conference:
end_date: 2018-05-03
location: Tel Aviv, Israel
name: 'Eurocrypt 2018: Advances in Cryptology'
start_date: 2018-04-29
date_created: 2018-12-11T11:45:41Z
date_published: 2018-03-31T00:00:00Z
date_updated: 2023-09-19T09:59:30Z
day: '31'
department:
- _id: KrPi
doi: 10.1007/978-3-319-78375-8_4
ec_funded: 1
external_id:
arxiv:
- '1705.05313'
isi:
- '000517098700004'
intvolume: ' 10821'
isi: 1
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://arxiv.org/abs/1705.05313
month: '03'
oa: 1
oa_version: Preprint
page: 99 - 130
project:
- _id: 258AA5B2-B435-11E9-9278-68D0E5697425
call_identifier: H2020
grant_number: '682815'
name: Teaching Old Crypto New Tricks
publication_status: published
publisher: Springer
publist_id: '7583'
quality_controlled: '1'
scopus_import: '1'
status: public
title: Sustained space complexity
type: conference
user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1
volume: 10821
year: '2018'
...
---
_id: '300'
abstract:
- lang: eng
text: We introduce a formal quantitative notion of “bit security” for a general
type of cryptographic games (capturing both decision and search problems), aimed
at capturing the intuition that a cryptographic primitive with k-bit security
is as hard to break as an ideal cryptographic function requiring a brute force
attack on a k-bit key space. Our new definition matches the notion of bit security
commonly used by cryptographers and cryptanalysts when studying search (e.g.,
key recovery) problems, where the use of the traditional definition is well established.
However, it produces a quantitatively different metric in the case of decision
(indistinguishability) problems, where the use of (a straightforward generalization
of) the traditional definition is more problematic and leads to a number of paradoxical
situations or mismatches between theoretical/provable security and practical/common
sense intuition. Key to our new definition is to consider adversaries that may
explicitly declare failure of the attack. We support and justify the new definition
by proving a number of technical results, including tight reductions between several
standard cryptographic problems, a new hybrid theorem that preserves bit security,
and an application to the security analysis of indistinguishability primitives
making use of (approximate) floating point numbers. This is the first result showing
that (standard precision) 53-bit floating point numbers can be used to achieve
100-bit security in the context of cryptographic primitives with general indistinguishability-based
security definitions. Previous results of this type applied only to search problems,
or special types of decision problems.
acknowledgement: Research supported in part by the Defense Advanced Research Projects
Agency (DARPA) and the U.S. Army Research Office under the SafeWare program. Opinions,
findings and conclusions or recommendations expressed in this material are those
of the author(s) and do not necessarily reflect the views, position or policy of
the Government. The second author was also supported by the European Research Council,
ERC consolidator grant (682815 - TOCNeT).
alternative_title:
- LNCS
article_processing_charge: No
author:
- first_name: Daniele
full_name: Micciancio, Daniele
last_name: Micciancio
- first_name: Michael
full_name: Walter, Michael
id: 488F98B0-F248-11E8-B48F-1D18A9856A87
last_name: Walter
orcid: 0000-0003-3186-2482
citation:
ama: 'Micciancio D, Walter M. On the bit security of cryptographic primitives. In:
Vol 10820. Springer; 2018:3-28. doi:10.1007/978-3-319-78381-9_1'
apa: 'Micciancio, D., & Walter, M. (2018). On the bit security of cryptographic
primitives (Vol. 10820, pp. 3–28). Presented at the Eurocrypt: Advances in Cryptology,
Tel Aviv, Israel: Springer. https://doi.org/10.1007/978-3-319-78381-9_1'
chicago: Micciancio, Daniele, and Michael Walter. “On the Bit Security of Cryptographic
Primitives,” 10820:3–28. Springer, 2018. https://doi.org/10.1007/978-3-319-78381-9_1.
ieee: 'D. Micciancio and M. Walter, “On the bit security of cryptographic primitives,”
presented at the Eurocrypt: Advances in Cryptology, Tel Aviv, Israel, 2018, vol.
10820, pp. 3–28.'
ista: 'Micciancio D, Walter M. 2018. On the bit security of cryptographic primitives.
Eurocrypt: Advances in Cryptology, LNCS, vol. 10820, 3–28.'
mla: Micciancio, Daniele, and Michael Walter. On the Bit Security of Cryptographic
Primitives. Vol. 10820, Springer, 2018, pp. 3–28, doi:10.1007/978-3-319-78381-9_1.
short: D. Micciancio, M. Walter, in:, Springer, 2018, pp. 3–28.
conference:
end_date: 2018-05-03
location: Tel Aviv, Israel
name: 'Eurocrypt: Advances in Cryptology'
start_date: 2018-04-29
date_created: 2018-12-11T11:45:42Z
date_published: 2018-03-31T00:00:00Z
date_updated: 2023-09-13T09:12:04Z
day: '31'
department:
- _id: KrPi
doi: 10.1007/978-3-319-78381-9_1
ec_funded: 1
external_id:
isi:
- '000517097500001'
intvolume: ' 10820'
isi: 1
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://eprint.iacr.org/2018/077
month: '03'
oa: 1
oa_version: Submitted Version
page: 3 - 28
project:
- _id: 258AA5B2-B435-11E9-9278-68D0E5697425
call_identifier: H2020
grant_number: '682815'
name: Teaching Old Crypto New Tricks
publication_status: published
publisher: Springer
publist_id: '7581'
quality_controlled: '1'
scopus_import: '1'
status: public
title: On the bit security of cryptographic primitives
type: conference
user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1
volume: 10820
year: '2018'
...
---
_id: '302'
abstract:
- lang: eng
text: At ITCS 2013, Mahmoody, Moran and Vadhan [MMV13] introduce and construct publicly
verifiable proofs of sequential work, which is a protocol for proving that one
spent sequential computational work related to some statement. The original motivation
for such proofs included non-interactive time-stamping and universally verifiable
CPU benchmarks. A more recent application, and our main motivation, are blockchain
designs, where proofs of sequential work can be used – in combination with proofs
of space – as a more ecological and economical substitute for proofs of work which
are currently used to secure Bitcoin and other cryptocurrencies. The construction
proposed by [MMV13] is based on a hash function and can be proven secure in the
random oracle model, or assuming inherently sequential hash-functions, which is
a new standard model assumption introduced in their work. In a proof of sequential
work, a prover gets a “statement” χ, a time parameter N and access to a hash-function
H, which for the security proof is modelled as a random oracle. Correctness requires
that an honest prover can make a verifier accept making only N queries to H, while
soundness requires that any prover who makes the verifier accept must have made
(almost) N sequential queries to H. Thus a solution constitutes a proof that N
time passed since χ was received. Solutions must be publicly verifiable in time
at most polylogarithmic in N. The construction of [MMV13] is based on “depth-robust”
graphs, and as a consequence has rather poor concrete parameters. But the major
drawback is that the prover needs not just N time, but also N space to compute
a proof. In this work we propose a proof of sequential work which is much simpler,
more efficient and achieves much better concrete bounds. Most importantly, the
space required can be as small as log (N) (but we get better soundness using slightly
more memory than that). An open problem stated by [MMV13] that our construction
does not solve either is achieving a “unique” proof, where even a cheating prover
can only generate a single accepting proof. This property would be extremely useful
for applications to blockchains.
alternative_title:
- LNCS
article_processing_charge: No
author:
- first_name: Bram
full_name: Cohen, Bram
last_name: Cohen
- first_name: Krzysztof Z
full_name: Pietrzak, Krzysztof Z
id: 3E04A7AA-F248-11E8-B48F-1D18A9856A87
last_name: Pietrzak
orcid: 0000-0002-9139-1654
citation:
ama: 'Cohen B, Pietrzak KZ. Simple proofs of sequential work. In: Vol 10821. Springer;
2018:451-467. doi:10.1007/978-3-319-78375-8_15'
apa: 'Cohen, B., & Pietrzak, K. Z. (2018). Simple proofs of sequential work
(Vol. 10821, pp. 451–467). Presented at the Eurocrypt: Advances in Cryptology,
Tel Aviv, Israel: Springer. https://doi.org/10.1007/978-3-319-78375-8_15'
chicago: Cohen, Bram, and Krzysztof Z Pietrzak. “Simple Proofs of Sequential Work,”
10821:451–67. Springer, 2018. https://doi.org/10.1007/978-3-319-78375-8_15.
ieee: 'B. Cohen and K. Z. Pietrzak, “Simple proofs of sequential work,” presented
at the Eurocrypt: Advances in Cryptology, Tel Aviv, Israel, 2018, vol. 10821,
pp. 451–467.'
ista: 'Cohen B, Pietrzak KZ. 2018. Simple proofs of sequential work. Eurocrypt:
Advances in Cryptology, LNCS, vol. 10821, 451–467.'
mla: Cohen, Bram, and Krzysztof Z. Pietrzak. Simple Proofs of Sequential Work.
Vol. 10821, Springer, 2018, pp. 451–67, doi:10.1007/978-3-319-78375-8_15.
short: B. Cohen, K.Z. Pietrzak, in:, Springer, 2018, pp. 451–467.
conference:
end_date: 2018-05-03
location: Tel Aviv, Israel
name: 'Eurocrypt: Advances in Cryptology'
start_date: 2018-04-29
date_created: 2018-12-11T11:45:42Z
date_published: 2018-05-29T00:00:00Z
date_updated: 2023-09-18T09:29:33Z
day: '29'
department:
- _id: KrPi
doi: 10.1007/978-3-319-78375-8_15
ec_funded: 1
external_id:
isi:
- '000517098700015'
intvolume: ' 10821'
isi: 1
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://eprint.iacr.org/2018/183.pdf
month: '05'
oa: 1
oa_version: Submitted Version
page: 451 - 467
project:
- _id: 258AA5B2-B435-11E9-9278-68D0E5697425
call_identifier: H2020
grant_number: '682815'
name: Teaching Old Crypto New Tricks
publication_status: published
publisher: Springer
publist_id: '7579'
quality_controlled: '1'
scopus_import: '1'
status: public
title: Simple proofs of sequential work
type: conference
user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1
volume: 10821
year: '2018'
...
---
_id: '107'
abstract:
- lang: eng
text: 'We introduce the notion of “non-malleable codes” which relaxes the notion
of error correction and error detection. Informally, a code is non-malleable if
the message contained in a modified codeword is either the original message, or
a completely unrelated value. In contrast to error correction and error detection,
non-malleability can be achieved for very rich classes of modifications. We construct
an efficient code that is non-malleable with respect to modifications that affect
each bit of the codeword arbitrarily (i.e., leave it untouched, flip it, or set
it to either 0 or 1), but independently of the value of the other bits of the
codeword. Using the probabilistic method, we also show a very strong and general
statement: there exists a non-malleable code for every “small enough” family F
of functions via which codewords can be modified. Although this probabilistic
method argument does not directly yield efficient constructions, it gives us efficient
non-malleable codes in the random-oracle model for very general classes of tampering
functions—e.g., functions where every bit in the tampered codeword can depend
arbitrarily on any 99% of the bits in the original codeword. As an application
of non-malleable codes, we show that they provide an elegant algorithmic solution
to the task of protecting functionalities implemented in hardware (e.g., signature
cards) against “tampering attacks.” In such attacks, the secret state of a physical
system is tampered, in the hopes that future interaction with the modified system
will reveal some secret information. This problem was previously studied in the
work of Gennaro et al. in 2004 under the name “algorithmic tamper proof security”
(ATP). We show that non-malleable codes can be used to achieve important improvements
over the prior work. In particular, we show that any functionality can be made
secure against a large class of tampering attacks, simply by encoding the secret
state with a non-malleable code while it is stored in memory.'
article_number: '20'
article_processing_charge: No
article_type: original
author:
- first_name: Stefan
full_name: Dziembowski, Stefan
last_name: Dziembowski
- first_name: Krzysztof Z
full_name: Pietrzak, Krzysztof Z
id: 3E04A7AA-F248-11E8-B48F-1D18A9856A87
last_name: Pietrzak
orcid: 0000-0002-9139-1654
- first_name: Daniel
full_name: Wichs, Daniel
last_name: Wichs
citation:
ama: Dziembowski S, Pietrzak KZ, Wichs D. Non-malleable codes. Journal of the
ACM. 2018;65(4). doi:10.1145/3178432
apa: Dziembowski, S., Pietrzak, K. Z., & Wichs, D. (2018). Non-malleable codes.
Journal of the ACM. ACM. https://doi.org/10.1145/3178432
chicago: Dziembowski, Stefan, Krzysztof Z Pietrzak, and Daniel Wichs. “Non-Malleable
Codes.” Journal of the ACM. ACM, 2018. https://doi.org/10.1145/3178432.
ieee: S. Dziembowski, K. Z. Pietrzak, and D. Wichs, “Non-malleable codes,” Journal
of the ACM, vol. 65, no. 4. ACM, 2018.
ista: Dziembowski S, Pietrzak KZ, Wichs D. 2018. Non-malleable codes. Journal of
the ACM. 65(4), 20.
mla: Dziembowski, Stefan, et al. “Non-Malleable Codes.” Journal of the ACM,
vol. 65, no. 4, 20, ACM, 2018, doi:10.1145/3178432.
short: S. Dziembowski, K.Z. Pietrzak, D. Wichs, Journal of the ACM 65 (2018).
date_created: 2018-12-11T11:44:40Z
date_published: 2018-08-01T00:00:00Z
date_updated: 2023-09-13T09:05:17Z
day: '01'
department:
- _id: KrPi
doi: 10.1145/3178432
ec_funded: 1
external_id:
isi:
- '000442938200004'
intvolume: ' 65'
isi: 1
issue: '4'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://eprint.iacr.org/2009/608
month: '08'
oa: 1
oa_version: Preprint
project:
- _id: 258AA5B2-B435-11E9-9278-68D0E5697425
call_identifier: H2020
grant_number: '682815'
name: Teaching Old Crypto New Tricks
- _id: 258C570E-B435-11E9-9278-68D0E5697425
call_identifier: FP7
grant_number: '259668'
name: Provable Security for Physical Cryptography
publication: Journal of the ACM
publication_status: published
publisher: ACM
publist_id: '7947'
quality_controlled: '1'
scopus_import: '1'
status: public
title: Non-malleable codes
type: journal_article
user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1
volume: 65
year: '2018'
...
---
_id: '108'
abstract:
- lang: eng
text: Universal hashing found a lot of applications in computer science. In cryptography
the most important fact about universal families is the so called Leftover Hash
Lemma, proved by Impagliazzo, Levin and Luby. In the language of modern cryptography
it states that almost universal families are good extractors. In this work we
provide a somewhat surprising characterization in the opposite direction. Namely,
every extractor with sufficiently good parameters yields a universal family on
a noticeable fraction of its inputs. Our proof technique is based on tools from
extremal graph theory applied to the \'collision graph\' induced by the extractor,
and may be of independent interest. We discuss possible applications to the theory
of randomness extractors and non-malleable codes.
alternative_title:
- ISIT Proceedings
article_processing_charge: No
author:
- first_name: Marciej
full_name: Obremski, Marciej
last_name: Obremski
- first_name: Maciej
full_name: Skorski, Maciej
id: EC09FA6A-02D0-11E9-8223-86B7C91467DD
last_name: Skorski
citation:
ama: 'Obremski M, Skórski M. Inverted leftover hash lemma. In: Vol 2018. IEEE; 2018.
doi:10.1109/ISIT.2018.8437654'
apa: 'Obremski, M., & Skórski, M. (2018). Inverted leftover hash lemma (Vol.
2018). Presented at the ISIT: International Symposium on Information Theory, Vail,
CO, USA: IEEE. https://doi.org/10.1109/ISIT.2018.8437654'
chicago: Obremski, Marciej, and Maciej Skórski. “Inverted Leftover Hash Lemma,”
Vol. 2018. IEEE, 2018. https://doi.org/10.1109/ISIT.2018.8437654.
ieee: 'M. Obremski and M. Skórski, “Inverted leftover hash lemma,” presented at
the ISIT: International Symposium on Information Theory, Vail, CO, USA, 2018,
vol. 2018.'
ista: 'Obremski M, Skórski M. 2018. Inverted leftover hash lemma. ISIT: International
Symposium on Information Theory, ISIT Proceedings, vol. 2018.'
mla: Obremski, Marciej, and Maciej Skórski. Inverted Leftover Hash Lemma.
Vol. 2018, IEEE, 2018, doi:10.1109/ISIT.2018.8437654.
short: M. Obremski, M. Skórski, in:, IEEE, 2018.
conference:
end_date: 2018-06-22
location: Vail, CO, USA
name: 'ISIT: International Symposium on Information Theory'
start_date: '2018-06-17 '
date_created: 2018-12-11T11:44:40Z
date_published: 2018-08-16T00:00:00Z
date_updated: 2023-09-13T08:23:18Z
day: '16'
department:
- _id: KrPi
doi: 10.1109/ISIT.2018.8437654
external_id:
isi:
- '000448139300368'
intvolume: ' 2018'
isi: 1
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://eprint.iacr.org/2017/507
month: '08'
oa: 1
oa_version: Submitted Version
publication_status: published
publisher: IEEE
publist_id: '7946'
quality_controlled: '1'
scopus_import: '1'
status: public
title: Inverted leftover hash lemma
type: conference
user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1
volume: 2018
year: '2018'
...
---
_id: '83'
abstract:
- lang: eng
text: "A proof system is a protocol between a prover and a verifier over a common
input in which an honest prover convinces the verifier of the validity of true
statements. Motivated by the success of decentralized cryptocurrencies, exemplified
by Bitcoin, the focus of this thesis will be on proof systems which found applications
in some sustainable alternatives to Bitcoin, such as the Spacemint and Chia cryptocurrencies.
In particular, we focus on proofs of space and proofs of sequential work.\r\nProofs
of space (PoSpace) were suggested as more ecological, economical, and egalitarian
alternative to the energy-wasteful proof-of-work mining of Bitcoin. However, the
state-of-the-art constructions of PoSpace are based on sophisticated graph pebbling
lower bounds, and are therefore complex. Moreover, when these PoSpace are used
in cryptocurrencies like Spacemint, miners can only start mining after ensuring
that a commitment to their space is already added in a special transaction to
the blockchain. Proofs of sequential work (PoSW) are proof systems in which a
prover, upon receiving a statement x and a time parameter T, computes a proof
which convinces the verifier that T time units had passed since x was received.
Whereas Spacemint assumes synchrony to retain some interesting Bitcoin dynamics,
Chia requires PoSW with unique proofs, i.e., PoSW in which it is hard to come
up with more than one accepting proof for any true statement. In this thesis we
construct simple and practically-efficient PoSpace and PoSW. When using our PoSpace
in cryptocurrencies, miners can start mining on the fly, like in Bitcoin, and
unlike current constructions of PoSW, which either achieve efficient verification
of sequential work, or faster-than-recomputing verification of correctness of
proofs, but not both at the same time, ours achieve the best of these two worlds."
alternative_title:
- ISTA Thesis
article_processing_charge: No
author:
- first_name: Hamza M
full_name: Abusalah, Hamza M
id: 40297222-F248-11E8-B48F-1D18A9856A87
last_name: Abusalah
citation:
ama: Abusalah HM. Proof systems for sustainable decentralized cryptocurrencies.
2018. doi:10.15479/AT:ISTA:TH_1046
apa: Abusalah, H. M. (2018). Proof systems for sustainable decentralized cryptocurrencies.
Institute of Science and Technology Austria. https://doi.org/10.15479/AT:ISTA:TH_1046
chicago: Abusalah, Hamza M. “Proof Systems for Sustainable Decentralized Cryptocurrencies.”
Institute of Science and Technology Austria, 2018. https://doi.org/10.15479/AT:ISTA:TH_1046.
ieee: H. M. Abusalah, “Proof systems for sustainable decentralized cryptocurrencies,”
Institute of Science and Technology Austria, 2018.
ista: Abusalah HM. 2018. Proof systems for sustainable decentralized cryptocurrencies.
Institute of Science and Technology Austria.
mla: Abusalah, Hamza M. Proof Systems for Sustainable Decentralized Cryptocurrencies.
Institute of Science and Technology Austria, 2018, doi:10.15479/AT:ISTA:TH_1046.
short: H.M. Abusalah, Proof Systems for Sustainable Decentralized Cryptocurrencies,
Institute of Science and Technology Austria, 2018.
date_created: 2018-12-11T11:44:32Z
date_published: 2018-09-05T00:00:00Z
date_updated: 2023-09-07T12:30:23Z
day: '05'
ddc:
- '004'
degree_awarded: PhD
department:
- _id: KrPi
doi: 10.15479/AT:ISTA:TH_1046
ec_funded: 1
file:
- access_level: open_access
checksum: c4b5f7d111755d1396787f41886fc674
content_type: application/pdf
creator: dernst
date_created: 2019-04-09T06:43:41Z
date_updated: 2020-07-14T12:48:11Z
file_id: '6245'
file_name: 2018_Thesis_Abusalah.pdf
file_size: 876241
relation: main_file
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checksum: 0f382ac56b471c48fd907d63eb87dafe
content_type: application/x-gzip
creator: dernst
date_created: 2019-04-09T06:43:41Z
date_updated: 2020-07-14T12:48:11Z
file_id: '6246'
file_name: 2018_Thesis_Abusalah_source.tar.gz
file_size: 2029190
relation: source_file
file_date_updated: 2020-07-14T12:48:11Z
has_accepted_license: '1'
language:
- iso: eng
month: '09'
oa: 1
oa_version: Published Version
page: '59'
project:
- _id: 258C570E-B435-11E9-9278-68D0E5697425
call_identifier: FP7
grant_number: '259668'
name: Provable Security for Physical Cryptography
- _id: 258AA5B2-B435-11E9-9278-68D0E5697425
call_identifier: H2020
grant_number: '682815'
name: Teaching Old Crypto New Tricks
publication_identifier:
issn:
- 2663-337X
publication_status: published
publisher: Institute of Science and Technology Austria
publist_id: '7971'
pubrep_id: '1046'
related_material:
record:
- id: '1229'
relation: part_of_dissertation
status: public
- id: '1235'
relation: part_of_dissertation
status: public
- id: '1236'
relation: part_of_dissertation
status: public
- id: '559'
relation: part_of_dissertation
status: public
status: public
supervisor:
- first_name: Krzysztof Z
full_name: Pietrzak, Krzysztof Z
id: 3E04A7AA-F248-11E8-B48F-1D18A9856A87
last_name: Pietrzak
orcid: 0000-0002-9139-1654
title: Proof systems for sustainable decentralized cryptocurrencies
type: dissertation
user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1
year: '2018'
...
---
_id: '193'
abstract:
- lang: eng
text: 'We show attacks on five data-independent memory-hard functions (iMHF) that
were submitted to the password hashing competition (PHC). Informally, an MHF is
a function which cannot be evaluated on dedicated hardware, like ASICs, at significantly
lower hardware and/or energy cost than evaluating a single instance on a standard
single-core architecture. Data-independent means the memory access pattern of
the function is independent of the input; this makes iMHFs harder to construct
than data-dependent ones, but the latter can be attacked by various side-channel
attacks. Following [Alwen-Blocki''16], we capture the evaluation of an iMHF as
a directed acyclic graph (DAG). The cumulative parallel pebbling complexity of
this DAG is a measure for the hardware cost of evaluating the iMHF on an ASIC.
Ideally, one would like the complexity of a DAG underlying an iMHF to be as close
to quadratic in the number of nodes of the graph as possible. Instead, we show
that (the DAGs underlying) the following iMHFs are far from this bound: Rig.v2,
TwoCats and Gambit each having an exponent no more than 1.75. Moreover, we show
that the complexity of the iMHF modes of the PHC finalists Pomelo and Lyra2 have
exponents at most 1.83 and 1.67 respectively. To show this we investigate a combinatorial
property of each underlying DAG (called its depth-robustness. By establishing
upper bounds on this property we are then able to apply the general technique
of [Alwen-Block''16] for analyzing the hardware costs of an iMHF.'
acknowledgement: Leonid Reyzin was supported in part by IST Austria and by US NSF
grants 1012910, 1012798, and 1422965; this research was performed while he was visiting
IST Austria.
article_processing_charge: No
author:
- first_name: Joel F
full_name: Alwen, Joel F
id: 2A8DFA8C-F248-11E8-B48F-1D18A9856A87
last_name: Alwen
- first_name: Peter
full_name: Gazi, Peter
last_name: Gazi
- first_name: Chethan
full_name: Kamath Hosdurg, Chethan
id: 4BD3F30E-F248-11E8-B48F-1D18A9856A87
last_name: Kamath Hosdurg
- first_name: Karen
full_name: Klein, Karen
id: 3E83A2F8-F248-11E8-B48F-1D18A9856A87
last_name: Klein
- first_name: Georg F
full_name: Osang, Georg F
id: 464B40D6-F248-11E8-B48F-1D18A9856A87
last_name: Osang
orcid: 0000-0002-8882-5116
- first_name: Krzysztof Z
full_name: Pietrzak, Krzysztof Z
id: 3E04A7AA-F248-11E8-B48F-1D18A9856A87
last_name: Pietrzak
orcid: 0000-0002-9139-1654
- first_name: Lenoid
full_name: Reyzin, Lenoid
last_name: Reyzin
- first_name: Michal
full_name: Rolinek, Michal
id: 3CB3BC06-F248-11E8-B48F-1D18A9856A87
last_name: Rolinek
- first_name: Michal
full_name: Rybar, Michal
id: 2B3E3DE8-F248-11E8-B48F-1D18A9856A87
last_name: Rybar
citation:
ama: 'Alwen JF, Gazi P, Kamath Hosdurg C, et al. On the memory hardness of data
independent password hashing functions. In: Proceedings of the 2018 on Asia
Conference on Computer and Communication Security. ACM; 2018:51-65. doi:10.1145/3196494.3196534'
apa: 'Alwen, J. F., Gazi, P., Kamath Hosdurg, C., Klein, K., Osang, G. F., Pietrzak,
K. Z., … Rybar, M. (2018). On the memory hardness of data independent password
hashing functions. In Proceedings of the 2018 on Asia Conference on Computer
and Communication Security (pp. 51–65). Incheon, Republic of Korea: ACM. https://doi.org/10.1145/3196494.3196534'
chicago: Alwen, Joel F, Peter Gazi, Chethan Kamath Hosdurg, Karen Klein, Georg F
Osang, Krzysztof Z Pietrzak, Lenoid Reyzin, Michal Rolinek, and Michal Rybar.
“On the Memory Hardness of Data Independent Password Hashing Functions.” In Proceedings
of the 2018 on Asia Conference on Computer and Communication Security, 51–65.
ACM, 2018. https://doi.org/10.1145/3196494.3196534.
ieee: J. F. Alwen et al., “On the memory hardness of data independent password
hashing functions,” in Proceedings of the 2018 on Asia Conference on Computer
and Communication Security, Incheon, Republic of Korea, 2018, pp. 51–65.
ista: 'Alwen JF, Gazi P, Kamath Hosdurg C, Klein K, Osang GF, Pietrzak KZ, Reyzin
L, Rolinek M, Rybar M. 2018. On the memory hardness of data independent password
hashing functions. Proceedings of the 2018 on Asia Conference on Computer and
Communication Security. ASIACCS: Asia Conference on Computer and Communications
Security , 51–65.'
mla: Alwen, Joel F., et al. “On the Memory Hardness of Data Independent Password
Hashing Functions.” Proceedings of the 2018 on Asia Conference on Computer
and Communication Security, ACM, 2018, pp. 51–65, doi:10.1145/3196494.3196534.
short: J.F. Alwen, P. Gazi, C. Kamath Hosdurg, K. Klein, G.F. Osang, K.Z. Pietrzak,
L. Reyzin, M. Rolinek, M. Rybar, in:, Proceedings of the 2018 on Asia Conference
on Computer and Communication Security, ACM, 2018, pp. 51–65.
conference:
end_date: 2018-06-08
location: Incheon, Republic of Korea
name: 'ASIACCS: Asia Conference on Computer and Communications Security '
start_date: 2018-06-04
date_created: 2018-12-11T11:45:07Z
date_published: 2018-06-01T00:00:00Z
date_updated: 2023-09-13T09:13:12Z
day: '01'
department:
- _id: KrPi
- _id: HeEd
- _id: VlKo
doi: 10.1145/3196494.3196534
ec_funded: 1
external_id:
isi:
- '000516620100005'
isi: 1
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://eprint.iacr.org/2016/783
month: '06'
oa: 1
oa_version: Submitted Version
page: 51 - 65
project:
- _id: 25FBA906-B435-11E9-9278-68D0E5697425
call_identifier: FP7
grant_number: '616160'
name: 'Discrete Optimization in Computer Vision: Theory and Practice'
- _id: 258AA5B2-B435-11E9-9278-68D0E5697425
call_identifier: H2020
grant_number: '682815'
name: Teaching Old Crypto New Tricks
publication: Proceedings of the 2018 on Asia Conference on Computer and Communication
Security
publication_status: published
publisher: ACM
publist_id: '7723'
quality_controlled: '1'
scopus_import: '1'
status: public
title: On the memory hardness of data independent password hashing functions
type: conference
user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1
year: '2018'
...
---
_id: '6941'
abstract:
- lang: eng
text: "Bitcoin has become the most successful cryptocurrency ever deployed, and
its most distinctive feature is that it is decentralized. Its underlying protocol
(Nakamoto consensus) achieves this by using proof of work, which has the drawback
that it causes the consumption of vast amounts of energy to maintain the ledger.
Moreover, Bitcoin mining dynamics have become less distributed over time.\r\n\r\nTowards
addressing these issues, we propose SpaceMint, a cryptocurrency based on proofs
of space instead of proofs of work. Miners in SpaceMint dedicate disk space rather
than computation. We argue that SpaceMint’s design solves or alleviates several
of Bitcoin’s issues: most notably, its large energy consumption. SpaceMint also
rewards smaller miners fairly according to their contribution to the network,
thus incentivizing more distributed participation.\r\n\r\nThis paper adapts proof
of space to enable its use in cryptocurrency, studies the attacks that can arise
against a Bitcoin-like blockchain that uses proof of space, and proposes a new
blockchain format and transaction types to address these attacks. Our prototype
shows that initializing 1 TB for mining takes about a day (a one-off setup cost),
and miners spend on average just a fraction of a second per block mined. Finally,
we provide a game-theoretic analysis modeling SpaceMint as an extensive game (the
canonical game-theoretic notion for games that take place over time) and show
that this stylized game satisfies a strong equilibrium notion, thereby arguing
for SpaceMint ’s stability and consensus."
alternative_title:
- LNCS
article_processing_charge: No
author:
- first_name: Sunoo
full_name: Park, Sunoo
last_name: Park
- first_name: Albert
full_name: Kwon, Albert
last_name: Kwon
- first_name: Georg
full_name: Fuchsbauer, Georg
id: 46B4C3EE-F248-11E8-B48F-1D18A9856A87
last_name: Fuchsbauer
- first_name: Peter
full_name: Gazi, Peter
id: 3E0BFE38-F248-11E8-B48F-1D18A9856A87
last_name: Gazi
- first_name: Joel F
full_name: Alwen, Joel F
id: 2A8DFA8C-F248-11E8-B48F-1D18A9856A87
last_name: Alwen
- first_name: Krzysztof Z
full_name: Pietrzak, Krzysztof Z
id: 3E04A7AA-F248-11E8-B48F-1D18A9856A87
last_name: Pietrzak
orcid: 0000-0002-9139-1654
citation:
ama: 'Park S, Kwon A, Fuchsbauer G, Gazi P, Alwen JF, Pietrzak KZ. SpaceMint: A
cryptocurrency based on proofs of space. In: 22nd International Conference
on Financial Cryptography and Data Security. Vol 10957. Springer Nature; 2018:480-499.
doi:10.1007/978-3-662-58387-6_26'
apa: 'Park, S., Kwon, A., Fuchsbauer, G., Gazi, P., Alwen, J. F., & Pietrzak,
K. Z. (2018). SpaceMint: A cryptocurrency based on proofs of space. In 22nd
International Conference on Financial Cryptography and Data Security (Vol.
10957, pp. 480–499). Nieuwpoort, Curacao: Springer Nature. https://doi.org/10.1007/978-3-662-58387-6_26'
chicago: 'Park, Sunoo, Albert Kwon, Georg Fuchsbauer, Peter Gazi, Joel F Alwen,
and Krzysztof Z Pietrzak. “SpaceMint: A Cryptocurrency Based on Proofs of Space.”
In 22nd International Conference on Financial Cryptography and Data Security,
10957:480–99. Springer Nature, 2018. https://doi.org/10.1007/978-3-662-58387-6_26.'
ieee: 'S. Park, A. Kwon, G. Fuchsbauer, P. Gazi, J. F. Alwen, and K. Z. Pietrzak,
“SpaceMint: A cryptocurrency based on proofs of space,” in 22nd International
Conference on Financial Cryptography and Data Security, Nieuwpoort, Curacao,
2018, vol. 10957, pp. 480–499.'
ista: 'Park S, Kwon A, Fuchsbauer G, Gazi P, Alwen JF, Pietrzak KZ. 2018. SpaceMint:
A cryptocurrency based on proofs of space. 22nd International Conference on Financial
Cryptography and Data Security. FC: Financial Cryptography and Data Security,
LNCS, vol. 10957, 480–499.'
mla: 'Park, Sunoo, et al. “SpaceMint: A Cryptocurrency Based on Proofs of Space.”
22nd International Conference on Financial Cryptography and Data Security,
vol. 10957, Springer Nature, 2018, pp. 480–99, doi:10.1007/978-3-662-58387-6_26.'
short: S. Park, A. Kwon, G. Fuchsbauer, P. Gazi, J.F. Alwen, K.Z. Pietrzak, in:,
22nd International Conference on Financial Cryptography and Data Security, Springer
Nature, 2018, pp. 480–499.
conference:
end_date: 2018-03-02
location: Nieuwpoort, Curacao
name: 'FC: Financial Cryptography and Data Security'
start_date: 2018-02-26
date_created: 2019-10-14T06:35:38Z
date_published: 2018-12-07T00:00:00Z
date_updated: 2023-09-19T15:02:13Z
day: '07'
department:
- _id: KrPi
doi: 10.1007/978-3-662-58387-6_26
ec_funded: 1
external_id:
isi:
- '000540656400026'
intvolume: ' 10957'
isi: 1
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://eprint.iacr.org/2015/528
month: '12'
oa: 1
oa_version: Submitted Version
page: 480-499
project:
- _id: 258AA5B2-B435-11E9-9278-68D0E5697425
call_identifier: H2020
grant_number: '682815'
name: Teaching Old Crypto New Tricks
publication: 22nd International Conference on Financial Cryptography and Data Security
publication_identifier:
eissn:
- 1611-3349
isbn:
- '9783662583869'
- '9783662583876'
issn:
- 0302-9743
publication_status: published
publisher: Springer Nature
quality_controlled: '1'
scopus_import: '1'
status: public
title: 'SpaceMint: A cryptocurrency based on proofs of space'
type: conference
user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1
volume: 10957
year: '2018'
...
---
_id: '7407'
abstract:
- lang: eng
text: 'Proofs of space (PoS) [Dziembowski et al., CRYPTO''15] are proof systems
where a prover can convince a verifier that he "wastes" disk space. PoS were introduced
as a more ecological and economical replacement for proofs of work which are currently
used to secure blockchains like Bitcoin. In this work we investigate extensions
of PoS which allow the prover to embed useful data into the dedicated space, which
later can be recovered. Our first contribution is a security proof for the original
PoS from CRYPTO''15 in the random oracle model (the original proof only applied
to a restricted class of adversaries which can store a subset of the data an honest
prover would store). When this PoS is instantiated with recent constructions of
maximally depth robust graphs, our proof implies basically optimal security. As
a second contribution we show three different extensions of this PoS where useful
data can be embedded into the space required by the prover. Our security proof
for the PoS extends (non-trivially) to these constructions. We discuss how some
of these variants can be used as proofs of catalytic space (PoCS), a notion we
put forward in this work, and which basically is a PoS where most of the space
required by the prover can be used to backup useful data. Finally we discuss how
one of the extensions is a candidate construction for a proof of replication (PoR),
a proof system recently suggested in the Filecoin whitepaper. '
alternative_title:
- LIPIcs
article_processing_charge: No
author:
- first_name: Krzysztof Z
full_name: Pietrzak, Krzysztof Z
id: 3E04A7AA-F248-11E8-B48F-1D18A9856A87
last_name: Pietrzak
orcid: 0000-0002-9139-1654
citation:
ama: 'Pietrzak KZ. Proofs of catalytic space. In: 10th Innovations in Theoretical
Computer Science Conference (ITCS 2019). Vol 124. Schloss Dagstuhl - Leibniz-Zentrum
für Informatik; 2018:59:1-59:25. doi:10.4230/LIPICS.ITCS.2019.59'
apa: 'Pietrzak, K. Z. (2018). Proofs of catalytic space. In 10th Innovations
in Theoretical Computer Science Conference (ITCS 2019) (Vol. 124, p. 59:1-59:25).
San Diego, CA, United States: Schloss Dagstuhl - Leibniz-Zentrum für Informatik.
https://doi.org/10.4230/LIPICS.ITCS.2019.59'
chicago: Pietrzak, Krzysztof Z. “Proofs of Catalytic Space.” In 10th Innovations
in Theoretical Computer Science Conference (ITCS 2019), 124:59:1-59:25. Schloss
Dagstuhl - Leibniz-Zentrum für Informatik, 2018. https://doi.org/10.4230/LIPICS.ITCS.2019.59.
ieee: K. Z. Pietrzak, “Proofs of catalytic space,” in 10th Innovations in Theoretical
Computer Science Conference (ITCS 2019), San Diego, CA, United States, 2018,
vol. 124, p. 59:1-59:25.
ista: 'Pietrzak KZ. 2018. Proofs of catalytic space. 10th Innovations in Theoretical
Computer Science Conference (ITCS 2019). ITCS: Innovations in theoretical Computer
Science Conference, LIPIcs, vol. 124, 59:1-59:25.'
mla: Pietrzak, Krzysztof Z. “Proofs of Catalytic Space.” 10th Innovations in
Theoretical Computer Science Conference (ITCS 2019), vol. 124, Schloss Dagstuhl
- Leibniz-Zentrum für Informatik, 2018, p. 59:1-59:25, doi:10.4230/LIPICS.ITCS.2019.59.
short: K.Z. Pietrzak, in:, 10th Innovations in Theoretical Computer Science Conference
(ITCS 2019), Schloss Dagstuhl - Leibniz-Zentrum für Informatik, 2018, p. 59:1-59:25.
conference:
end_date: 2019-01-12
location: San Diego, CA, United States
name: 'ITCS: Innovations in theoretical Computer Science Conference'
start_date: 2019-01-10
date_created: 2020-01-30T09:16:05Z
date_published: 2018-12-31T00:00:00Z
date_updated: 2021-01-12T08:13:26Z
day: '31'
ddc:
- '000'
department:
- _id: KrPi
doi: 10.4230/LIPICS.ITCS.2019.59
ec_funded: 1
file:
- access_level: open_access
checksum: 5cebb7f7849a3beda898f697d755dd96
content_type: application/pdf
creator: dernst
date_created: 2020-02-04T08:17:52Z
date_updated: 2020-07-14T12:47:57Z
file_id: '7443'
file_name: 2018_LIPIcs_Pietrzak.pdf
file_size: 822884
relation: main_file
file_date_updated: 2020-07-14T12:47:57Z
has_accepted_license: '1'
intvolume: ' 124'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://eprint.iacr.org/2018/194
month: '12'
oa: 1
oa_version: Published Version
page: 59:1-59:25
project:
- _id: 258AA5B2-B435-11E9-9278-68D0E5697425
call_identifier: H2020
grant_number: '682815'
name: Teaching Old Crypto New Tricks
publication: 10th Innovations in Theoretical Computer Science Conference (ITCS 2019)
publication_identifier:
isbn:
- 978-3-95977-095-8
issn:
- 1868-8969
publication_status: published
publisher: Schloss Dagstuhl - Leibniz-Zentrum für Informatik
quality_controlled: '1'
scopus_import: 1
status: public
title: Proofs of catalytic space
tmp:
image: /images/cc_by.png
legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
short: CC BY (4.0)
type: conference
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 124
year: '2018'
...
---
_id: '5980'
abstract:
- lang: eng
text: The problem of private set-intersection (PSI) has been traditionally treated
as an instance of the more general problem of multi-party computation (MPC). Consequently,
in order to argue security, or compose these protocols one has to rely on the
general theory that was developed for the purpose of MPC. The pursuit of efficient
protocols, however, has resulted in designs that exploit properties pertaining
to PSI. In almost all practical applications where a PSI protocol is deployed,
it is expected to be executed multiple times, possibly on related inputs. In this
work we initiate a dedicated study of PSI in the multi-interaction (MI) setting.
In this model a server sets up the common system parameters and executes set-intersection
multiple times with potentially different clients. We discuss a few attacks that
arise when protocols are naïvely composed in this manner and, accordingly, craft
security definitions for the MI setting and study their inter-relation. Finally,
we suggest a set of protocols that are MI-secure, at the same time almost as efficient
as their parent, stand-alone, protocols.
article_processing_charge: No
author:
- first_name: Sanjit
full_name: Chatterjee, Sanjit
last_name: Chatterjee
- first_name: Chethan
full_name: Kamath Hosdurg, Chethan
id: 4BD3F30E-F248-11E8-B48F-1D18A9856A87
last_name: Kamath Hosdurg
- first_name: Vikas
full_name: Kumar, Vikas
last_name: Kumar
citation:
ama: Chatterjee S, Kamath Hosdurg C, Kumar V. Private set-intersection with common
set-up. American Institute of Mathematical Sciences. 2018;12(1):17-47.
doi:10.3934/amc.2018002
apa: Chatterjee, S., Kamath Hosdurg, C., & Kumar, V. (2018). Private set-intersection
with common set-up. American Institute of Mathematical Sciences. AIMS.
https://doi.org/10.3934/amc.2018002
chicago: Chatterjee, Sanjit, Chethan Kamath Hosdurg, and Vikas Kumar. “Private Set-Intersection
with Common Set-Up.” American Institute of Mathematical Sciences. AIMS,
2018. https://doi.org/10.3934/amc.2018002.
ieee: S. Chatterjee, C. Kamath Hosdurg, and V. Kumar, “Private set-intersection
with common set-up,” American Institute of Mathematical Sciences, vol.
12, no. 1. AIMS, pp. 17–47, 2018.
ista: Chatterjee S, Kamath Hosdurg C, Kumar V. 2018. Private set-intersection with
common set-up. American Institute of Mathematical Sciences. 12(1), 17–47.
mla: Chatterjee, Sanjit, et al. “Private Set-Intersection with Common Set-Up.” American
Institute of Mathematical Sciences, vol. 12, no. 1, AIMS, 2018, pp. 17–47,
doi:10.3934/amc.2018002.
short: S. Chatterjee, C. Kamath Hosdurg, V. Kumar, American Institute of Mathematical
Sciences 12 (2018) 17–47.
date_created: 2019-02-13T13:49:41Z
date_published: 2018-02-01T00:00:00Z
date_updated: 2023-09-19T14:27:59Z
day: '01'
department:
- _id: KrPi
doi: 10.3934/amc.2018002
external_id:
isi:
- '000430950400002'
intvolume: ' 12'
isi: 1
issue: '1'
language:
- iso: eng
month: '02'
oa_version: None
page: 17-47
publication: American Institute of Mathematical Sciences
publication_status: published
publisher: AIMS
quality_controlled: '1'
scopus_import: '1'
status: public
title: Private set-intersection with common set-up
type: journal_article
user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1
volume: 12
year: '2018'
...
---
_id: '10286'
abstract:
- lang: eng
text: 'In this paper, we evaluate clock signals generated in ring oscillators and
self-timed rings and the way their jitter can be transformed into random numbers.
We show that counting the periods of the jittery clock signal produces random
numbers of significantly better quality than the methods in which the jittery
signal is simply sampled (the case in almost all current methods). Moreover, we
use the counter values to characterize and continuously monitor the source of
randomness. However, instead of using the widely used statistical variance, we
propose to use Allan variance to do so. There are two main advantages: Allan variance
is insensitive to low frequency noises such as flicker noise that are known to
be autocorrelated and significantly less circuitry is required for its computation
than that used to compute commonly used variance. We also show that it is essential
to use a differential principle of randomness extraction from the jitter based
on the use of two identical oscillators to avoid autocorrelations originating
from external and internal global jitter sources and that this fact is valid for
both kinds of rings. Last but not least, we propose a method of statistical testing
based on high order Markov model to show the reduced dependencies when the proposed
randomness extraction is applied.'
article_processing_charge: No
article_type: original
author:
- first_name: Elie Noumon
full_name: Allini, Elie Noumon
last_name: Allini
- first_name: Maciej
full_name: Skórski, Maciej
id: EC09FA6A-02D0-11E9-8223-86B7C91467DD
last_name: Skórski
- first_name: Oto
full_name: Petura, Oto
last_name: Petura
- first_name: Florent
full_name: Bernard, Florent
last_name: Bernard
- first_name: Marek
full_name: Laban, Marek
last_name: Laban
- first_name: Viktor
full_name: Fischer, Viktor
last_name: Fischer
citation:
ama: Allini EN, Skórski M, Petura O, Bernard F, Laban M, Fischer V. Evaluation and
monitoring of free running oscillators serving as source of randomness. IACR
Transactions on Cryptographic Hardware and Embedded Systems. 2018;2018(3):214-242.
doi:10.13154/tches.v2018.i3.214-242
apa: Allini, E. N., Skórski, M., Petura, O., Bernard, F., Laban, M., & Fischer,
V. (2018). Evaluation and monitoring of free running oscillators serving as source
of randomness. IACR Transactions on Cryptographic Hardware and Embedded Systems.
International Association for Cryptologic Research. https://doi.org/10.13154/tches.v2018.i3.214-242
chicago: Allini, Elie Noumon, Maciej Skórski, Oto Petura, Florent Bernard, Marek
Laban, and Viktor Fischer. “Evaluation and Monitoring of Free Running Oscillators
Serving as Source of Randomness.” IACR Transactions on Cryptographic Hardware
and Embedded Systems. International Association for Cryptologic Research,
2018. https://doi.org/10.13154/tches.v2018.i3.214-242.
ieee: E. N. Allini, M. Skórski, O. Petura, F. Bernard, M. Laban, and V. Fischer,
“Evaluation and monitoring of free running oscillators serving as source of randomness,”
IACR Transactions on Cryptographic Hardware and Embedded Systems, vol.
2018, no. 3. International Association for Cryptologic Research, pp. 214–242,
2018.
ista: Allini EN, Skórski M, Petura O, Bernard F, Laban M, Fischer V. 2018. Evaluation
and monitoring of free running oscillators serving as source of randomness. IACR
Transactions on Cryptographic Hardware and Embedded Systems. 2018(3), 214–242.
mla: Allini, Elie Noumon, et al. “Evaluation and Monitoring of Free Running Oscillators
Serving as Source of Randomness.” IACR Transactions on Cryptographic Hardware
and Embedded Systems, vol. 2018, no. 3, International Association for Cryptologic
Research, 2018, pp. 214–42, doi:10.13154/tches.v2018.i3.214-242.
short: E.N. Allini, M. Skórski, O. Petura, F. Bernard, M. Laban, V. Fischer, IACR
Transactions on Cryptographic Hardware and Embedded Systems 2018 (2018) 214–242.
date_created: 2021-11-14T23:01:25Z
date_published: 2018-01-01T00:00:00Z
date_updated: 2021-11-15T10:48:49Z
day: '01'
ddc:
- '000'
department:
- _id: KrPi
doi: 10.13154/tches.v2018.i3.214-242
file:
- access_level: open_access
checksum: b816b848f046c48a8357700d9305dce5
content_type: application/pdf
creator: cchlebak
date_created: 2021-11-15T10:27:29Z
date_updated: 2021-11-15T10:27:29Z
file_id: '10289'
file_name: 2018_IACR_Allini.pdf
file_size: 955755
relation: main_file
success: 1
file_date_updated: 2021-11-15T10:27:29Z
has_accepted_license: '1'
intvolume: ' 2018'
issue: '3'
language:
- iso: eng
month: '01'
oa: 1
oa_version: Published Version
page: 214-242
publication: IACR Transactions on Cryptographic Hardware and Embedded Systems
publication_identifier:
eissn:
- 2569-2925
publication_status: published
publisher: International Association for Cryptologic Research
quality_controlled: '1'
scopus_import: '1'
status: public
title: Evaluation and monitoring of free running oscillators serving as source of
randomness
tmp:
image: /images/cc_by.png
legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
short: CC BY (4.0)
type: journal_article
user_id: 8b945eb4-e2f2-11eb-945a-df72226e66a9
volume: 2018
year: '2018'
...
---
_id: '1174'
abstract:
- lang: eng
text: Security of cryptographic applications is typically defined by security games.
The adversary, within certain resources, cannot win with probability much better
than 0 (for unpredictability applications, like one-way functions) or much better
than 1/2 (indistinguishability applications for instance encryption schemes).
In so called squared-friendly applications the winning probability of the adversary,
for different values of the application secret randomness, is not only close to
0 or 1/2 on average, but also concentrated in the sense that its second central
moment is small. The class of squared-friendly applications, which contains all
unpredictability applications and many indistinguishability applications, is particularly
important for key derivation. Barak et al. observed that for square-friendly applications
one can beat the "RT-bound", extracting secure keys with significantly
smaller entropy loss. In turn Dodis and Yu showed that in squared-friendly applications
one can directly use a "weak" key, which has only high entropy, as a
secure key. In this paper we give sharp lower bounds on square security assuming
security for "weak" keys. We show that any application which is either
(a) secure with weak keys or (b) allows for entropy savings for keys derived by
universal hashing, must be square-friendly. Quantitatively, our lower bounds match
the positive results of Dodis and Yu and Barak et al. (TCC\'13, CRYPTO\'11) Hence,
they can be understood as a general characterization of squared-friendly applications.
While the positive results on squared-friendly applications where derived by one
clever application of the Cauchy-Schwarz Inequality, for tight lower bounds we
need more machinery. In our approach we use convex optimization techniques and
some theory of circular matrices.
alternative_title:
- LIPIcs
article_number: '57'
article_processing_charge: No
author:
- first_name: Maciej
full_name: Skórski, Maciej
id: EC09FA6A-02D0-11E9-8223-86B7C91467DD
last_name: Skórski
citation:
ama: 'Skórski M. Lower bounds on key derivation for square-friendly applications.
In: Vol 66. Schloss Dagstuhl - Leibniz-Zentrum für Informatik; 2017. doi:10.4230/LIPIcs.STACS.2017.57'
apa: 'Skórski, M. (2017). Lower bounds on key derivation for square-friendly applications
(Vol. 66). Presented at the STACS: Symposium on Theoretical Aspects of Computer
Science, Hannover, Germany: Schloss Dagstuhl - Leibniz-Zentrum für Informatik.
https://doi.org/10.4230/LIPIcs.STACS.2017.57'
chicago: Skórski, Maciej. “Lower Bounds on Key Derivation for Square-Friendly Applications,”
Vol. 66. Schloss Dagstuhl - Leibniz-Zentrum für Informatik, 2017. https://doi.org/10.4230/LIPIcs.STACS.2017.57.
ieee: 'M. Skórski, “Lower bounds on key derivation for square-friendly applications,”
presented at the STACS: Symposium on Theoretical Aspects of Computer Science,
Hannover, Germany, 2017, vol. 66.'
ista: 'Skórski M. 2017. Lower bounds on key derivation for square-friendly applications.
STACS: Symposium on Theoretical Aspects of Computer Science, LIPIcs, vol. 66,
57.'
mla: Skórski, Maciej. Lower Bounds on Key Derivation for Square-Friendly Applications.
Vol. 66, 57, Schloss Dagstuhl - Leibniz-Zentrum für Informatik, 2017, doi:10.4230/LIPIcs.STACS.2017.57.
short: M. Skórski, in:, Schloss Dagstuhl - Leibniz-Zentrum für Informatik, 2017.
conference:
end_date: 2017-03-11
location: Hannover, Germany
name: 'STACS: Symposium on Theoretical Aspects of Computer Science'
start_date: 2017-03-08
date_created: 2018-12-11T11:50:32Z
date_published: 2017-03-01T00:00:00Z
date_updated: 2023-09-20T11:23:15Z
day: '01'
department:
- _id: KrPi
doi: 10.4230/LIPIcs.STACS.2017.57
ec_funded: 1
external_id:
isi:
- '000521077300057'
intvolume: ' 66'
isi: 1
language:
- iso: eng
main_file_link:
- open_access: '1'
url: http://drops.dagstuhl.de/opus/volltexte/2017/6976
month: '03'
oa: 1
oa_version: Submitted Version
project:
- _id: 258AA5B2-B435-11E9-9278-68D0E5697425
call_identifier: H2020
grant_number: '682815'
name: Teaching Old Crypto New Tricks
publication_identifier:
issn:
- '18688969'
publication_status: published
publisher: Schloss Dagstuhl - Leibniz-Zentrum für Informatik
publist_id: '6180'
quality_controlled: '1'
scopus_import: '1'
status: public
title: Lower bounds on key derivation for square-friendly applications
type: conference
user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1
volume: 66
year: '2017'
...
---
_id: '1175'
abstract:
- lang: eng
text: We study space complexity and time-space trade-offs with a focus not on peak
memory usage but on overall memory consumption throughout the computation. Such
a cumulative space measure was introduced for the computational model of parallel
black pebbling by [Alwen and Serbinenko ’15] as a tool for obtaining results in
cryptography. We consider instead the non- deterministic black-white pebble game
and prove optimal cumulative space lower bounds and trade-offs, where in order
to minimize pebbling time the space has to remain large during a significant fraction
of the pebbling. We also initiate the study of cumulative space in proof complexity,
an area where other space complexity measures have been extensively studied during
the last 10–15 years. Using and extending the connection between proof complexity
and pebble games in [Ben-Sasson and Nordström ’08, ’11] we obtain several strong
cumulative space results for (even parallel versions of) the resolution proof
system, and outline some possible future directions of study of this, in our opinion,
natural and interesting space measure.
alternative_title:
- LIPIcs
author:
- first_name: Joel F
full_name: Alwen, Joel F
id: 2A8DFA8C-F248-11E8-B48F-1D18A9856A87
last_name: Alwen
- first_name: Susanna
full_name: De Rezende, Susanna
last_name: De Rezende
- first_name: Jakob
full_name: Nordstrom, Jakob
last_name: Nordstrom
- first_name: Marc
full_name: Vinyals, Marc
last_name: Vinyals
citation:
ama: 'Alwen JF, De Rezende S, Nordstrom J, Vinyals M. Cumulative space in black-white
pebbling and resolution. In: Papadimitriou C, ed. Vol 67. Schloss Dagstuhl - Leibniz-Zentrum
für Informatik; 2017:38:1-38-21. doi:10.4230/LIPIcs.ITCS.2017.38'
apa: 'Alwen, J. F., De Rezende, S., Nordstrom, J., & Vinyals, M. (2017). Cumulative
space in black-white pebbling and resolution. In C. Papadimitriou (Ed.) (Vol.
67, p. 38:1-38-21). Presented at the ITCS: Innovations in Theoretical Computer
Science, Berkeley, CA, United States: Schloss Dagstuhl - Leibniz-Zentrum für Informatik.
https://doi.org/10.4230/LIPIcs.ITCS.2017.38'
chicago: Alwen, Joel F, Susanna De Rezende, Jakob Nordstrom, and Marc Vinyals. “Cumulative
Space in Black-White Pebbling and Resolution.” edited by Christos Papadimitriou,
67:38:1-38-21. Schloss Dagstuhl - Leibniz-Zentrum für Informatik, 2017. https://doi.org/10.4230/LIPIcs.ITCS.2017.38.
ieee: 'J. F. Alwen, S. De Rezende, J. Nordstrom, and M. Vinyals, “Cumulative space
in black-white pebbling and resolution,” presented at the ITCS: Innovations in
Theoretical Computer Science, Berkeley, CA, United States, 2017, vol. 67, p. 38:1-38-21.'
ista: 'Alwen JF, De Rezende S, Nordstrom J, Vinyals M. 2017. Cumulative space in
black-white pebbling and resolution. ITCS: Innovations in Theoretical Computer
Science, LIPIcs, vol. 67, 38:1-38-21.'
mla: Alwen, Joel F., et al. Cumulative Space in Black-White Pebbling and Resolution.
Edited by Christos Papadimitriou, vol. 67, Schloss Dagstuhl - Leibniz-Zentrum
für Informatik, 2017, p. 38:1-38-21, doi:10.4230/LIPIcs.ITCS.2017.38.
short: J.F. Alwen, S. De Rezende, J. Nordstrom, M. Vinyals, in:, C. Papadimitriou
(Ed.), Schloss Dagstuhl - Leibniz-Zentrum für Informatik, 2017, p. 38:1-38-21.
conference:
end_date: 2017-01-11
location: Berkeley, CA, United States
name: 'ITCS: Innovations in Theoretical Computer Science'
start_date: 2017-01-09
date_created: 2018-12-11T11:50:33Z
date_published: 2017-01-01T00:00:00Z
date_updated: 2021-01-12T06:48:51Z
day: '01'
ddc:
- '005'
- '600'
department:
- _id: KrPi
doi: 10.4230/LIPIcs.ITCS.2017.38
editor:
- first_name: Christos
full_name: Papadimitriou, Christos
last_name: Papadimitriou
file:
- access_level: open_access
checksum: dbc94810be07c2fb1945d5c2a6130e6c
content_type: application/pdf
creator: system
date_created: 2018-12-12T10:17:11Z
date_updated: 2020-07-14T12:44:37Z
file_id: '5263'
file_name: IST-2018-927-v1+1_LIPIcs-ITCS-2017-38.pdf
file_size: 557769
relation: main_file
file_date_updated: 2020-07-14T12:44:37Z
has_accepted_license: '1'
intvolume: ' 67'
language:
- iso: eng
month: '01'
oa: 1
oa_version: Published Version
page: 38:1-38-21
publication_identifier:
issn:
- '18688969'
publication_status: published
publisher: Schloss Dagstuhl - Leibniz-Zentrum für Informatik
publist_id: '6179'
pubrep_id: '927'
quality_controlled: '1'
scopus_import: 1
status: public
title: Cumulative space in black-white pebbling and resolution
tmp:
image: /images/cc_by.png
legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
short: CC BY (4.0)
type: conference
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 67
year: '2017'
...
---
_id: '1176'
abstract:
- lang: eng
text: The algorithm Argon2i-B of Biryukov, Dinu and Khovratovich is currently being
considered by the IRTF (Internet Research Task Force) as a new de-facto standard
for password hashing. An older version (Argon2i-A) of the same algorithm was chosen
as the winner of the recent Password Hashing Competition. An important competitor
to Argon2i-B is the recently introduced Balloon Hashing (BH) algorithm of Corrigan-Gibs,
Boneh and Schechter. A key security desiderata for any such algorithm is that
evaluating it (even using a custom device) requires a large amount of memory amortized
across multiple instances. Alwen and Blocki (CRYPTO 2016) introduced a class of
theoretical attacks against Argon2i-A and BH. While these attacks yield large
asymptotic reductions in the amount of memory, it was not, a priori, clear if
(1) they can be extended to the newer Argon2i-B, (2) the attacks are effective
on any algorithm for practical parameter ranges (e.g., 1GB of memory) and (3)
if they can be effectively instantiated against any algorithm under realistic
hardware constrains. In this work we answer all three of these questions in the
affirmative for all three algorithms. This is also the first work to analyze the
security of Argon2i-B. In more detail, we extend the theoretical attacks of Alwen
and Blocki (CRYPTO 2016) to the recent Argon2i-B proposal demonstrating severe
asymptotic deficiencies in its security. Next we introduce several novel heuristics
for improving the attack's concrete memory efficiency even when on-chip memory
bandwidth is bounded. We then simulate our attacks on randomly sampled Argon2i-A,
Argon2i-B and BH instances and measure the resulting memory consumption for various
practical parameter ranges and for a variety of upperbounds on the amount of parallelism
available to the attacker. Finally we describe, implement, and test a new heuristic
for applying the Alwen-Blocki attack to functions employing a technique developed
by Corrigan-Gibs et al. for improving concrete security of memory-hard functions.
We analyze the collected data and show the effects various parameters have on
the memory consumption of the attack. In particular, we can draw several interesting
conclusions about the level of security provided by these functions. · For the
Alwen-Blocki attack to fail against practical memory parameters, Argon2i-B must
be instantiated with more than 10 passes on memory - beyond the "paranoid" parameter
setting in the current IRTF proposal. · The technique of Corrigan-Gibs for improving
security can also be overcome by the Alwen-Blocki attack under realistic hardware
constraints. · On a positive note, both the asymptotic and concrete security of
Argon2i-B seem to improve on that of Argon2i-A.
article_number: '7961977'
article_processing_charge: No
author:
- first_name: Joel F
full_name: Alwen, Joel F
id: 2A8DFA8C-F248-11E8-B48F-1D18A9856A87
last_name: Alwen
- first_name: Jeremiah
full_name: Blocki, Jeremiah
last_name: Blocki
citation:
ama: 'Alwen JF, Blocki J. Towards practical attacks on Argon2i and balloon hashing.
In: IEEE; 2017. doi:10.1109/EuroSP.2017.47'
apa: 'Alwen, J. F., & Blocki, J. (2017). Towards practical attacks on Argon2i
and balloon hashing. Presented at the EuroS&P: European Symposium on Security
and Privacy, Paris, France: IEEE. https://doi.org/10.1109/EuroSP.2017.47'
chicago: Alwen, Joel F, and Jeremiah Blocki. “Towards Practical Attacks on Argon2i
and Balloon Hashing.” IEEE, 2017. https://doi.org/10.1109/EuroSP.2017.47.
ieee: 'J. F. Alwen and J. Blocki, “Towards practical attacks on Argon2i and balloon
hashing,” presented at the EuroS&P: European Symposium on Security and Privacy,
Paris, France, 2017.'
ista: 'Alwen JF, Blocki J. 2017. Towards practical attacks on Argon2i and balloon
hashing. EuroS&P: European Symposium on Security and Privacy, 7961977.'
mla: Alwen, Joel F., and Jeremiah Blocki. Towards Practical Attacks on Argon2i
and Balloon Hashing. 7961977, IEEE, 2017, doi:10.1109/EuroSP.2017.47.
short: J.F. Alwen, J. Blocki, in:, IEEE, 2017.
conference:
end_date: 2017-04-28
location: Paris, France
name: 'EuroS&P: European Symposium on Security and Privacy'
start_date: 2017-04-26
date_created: 2018-12-11T11:50:33Z
date_published: 2017-07-03T00:00:00Z
date_updated: 2023-09-20T11:22:25Z
day: '03'
department:
- _id: KrPi
doi: 10.1109/EuroSP.2017.47
external_id:
isi:
- '000424197300011'
isi: 1
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://eprint.iacr.org/2016/759
month: '07'
oa: 1
oa_version: Submitted Version
publication_identifier:
isbn:
- 978-150905761-0
publication_status: published
publisher: IEEE
publist_id: '6178'
quality_controlled: '1'
scopus_import: '1'
status: public
title: Towards practical attacks on Argon2i and balloon hashing
type: conference
user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1
year: '2017'
...
---
_id: '838'
abstract:
- lang: eng
text: 'In this thesis we discuss the exact security of message authentications codes
HMAC , NMAC , and PMAC . NMAC is a mode of operation which turns a fixed input-length
keyed hash function f into a variable input-length function. A practical single-key
variant of NMAC called HMAC is a very popular and widely deployed message authentication
code (MAC). PMAC is a block-cipher based mode of operation, which also happens
to be the most famous fully parallel MAC. NMAC was introduced by Bellare, Canetti
and Krawczyk Crypto’96, who proved it to be a secure pseudorandom function (PRF),
and thus also a MAC, under two assumptions. Unfortunately, for many instantiations
of HMAC one of them has been found to be wrong. To restore the provable guarantees
for NMAC , Bellare [Crypto’06] showed its security without this assumption. PMAC
was introduced by Black and Rogaway at Eurocrypt 2002. If instantiated with a
pseudorandom permutation over n -bit strings, PMAC constitutes a provably secure
variable input-length PRF. For adversaries making q queries, each of length at
most ` (in n -bit blocks), and of total length σ ≤ q` , the original paper proves
an upper bound on the distinguishing advantage of O ( σ 2 / 2 n ), while the currently
best bound is O ( qσ/ 2 n ). In this work we show that this bound is tight by
giving an attack with advantage Ω( q 2 `/ 2 n ). In the PMAC construction one
initially XORs a mask to every message block, where the mask for the i th block
is computed as τ i := γ i · L , where L is a (secret) random value, and γ i is
the i -th codeword of the Gray code. Our attack applies more generally to any
sequence of γ i ’s which contains a large coset of a subgroup of GF (2 n ). As
for NMAC , our first contribution is a simpler and uniform proof: If f is an ε
-secure PRF (against q queries) and a δ - non-adaptively secure PRF (against q
queries), then NMAC f is an ( ε + `qδ )-secure PRF against q queries of length
at most ` blocks each. We also show that this ε + `qδ bound is basically tight
by constructing an f for which an attack with advantage `qδ exists. Moreover,
we analyze the PRF-security of a modification of NMAC called NI by An and Bellare
that avoids the constant rekeying on multi-block messages in NMAC and allows for
an information-theoretic analysis. We carry out such an analysis, obtaining a
tight `q 2 / 2 c bound for this step, improving over the trivial bound of ` 2
q 2 / 2 c . Finally, we investigate, if the security of PMAC can be further improved
by using τ i ’s that are k -wise independent, for k > 1 (the original has k
= 1). We observe that the security of PMAC will not increase in general if k =
2, and then prove that the security increases to O ( q 2 / 2 n ), if the k = 4.
Due to simple extension attacks, this is the best bound one can hope for, using
any distribution on the masks. Whether k = 3 is already sufficient to get this
level of security is left as an open problem. Keywords: Message authentication
codes, Pseudorandom functions, HMAC, PMAC. '
alternative_title:
- ISTA Thesis
article_processing_charge: No
author:
- first_name: Michal
full_name: Rybar, Michal
id: 2B3E3DE8-F248-11E8-B48F-1D18A9856A87
last_name: Rybar
citation:
ama: Rybar M. (The exact security of) Message authentication codes. 2017. doi:10.15479/AT:ISTA:th_828
apa: Rybar, M. (2017). (The exact security of) Message authentication codes.
Institute of Science and Technology Austria. https://doi.org/10.15479/AT:ISTA:th_828
chicago: Rybar, Michal. “(The Exact Security of) Message Authentication Codes.”
Institute of Science and Technology Austria, 2017. https://doi.org/10.15479/AT:ISTA:th_828.
ieee: M. Rybar, “(The exact security of) Message authentication codes,” Institute
of Science and Technology Austria, 2017.
ista: Rybar M. 2017. (The exact security of) Message authentication codes. Institute
of Science and Technology Austria.
mla: Rybar, Michal. (The Exact Security of) Message Authentication Codes.
Institute of Science and Technology Austria, 2017, doi:10.15479/AT:ISTA:th_828.
short: M. Rybar, (The Exact Security of) Message Authentication Codes, Institute
of Science and Technology Austria, 2017.
date_created: 2018-12-11T11:48:46Z
date_published: 2017-06-26T00:00:00Z
date_updated: 2023-09-07T12:02:28Z
day: '26'
ddc:
- '000'
degree_awarded: PhD
department:
- _id: KrPi
doi: 10.15479/AT:ISTA:th_828
file:
- access_level: open_access
checksum: ff8639ec4bded6186f44c7bd3ee26804
content_type: application/pdf
creator: system
date_created: 2018-12-12T10:10:13Z
date_updated: 2020-07-14T12:48:12Z
file_id: '4799'
file_name: IST-2017-828-v1+3_2017_Rybar_thesis.pdf
file_size: 847400
relation: main_file
- access_level: closed
checksum: 3462101745ce8ad199c2d0f75dae4a7e
content_type: application/zip
creator: dernst
date_created: 2019-04-05T08:24:11Z
date_updated: 2020-07-14T12:48:12Z
file_id: '6202'
file_name: 2017_Thesis_Rybar_source.zip
file_size: 26054879
relation: source_file
file_date_updated: 2020-07-14T12:48:12Z
has_accepted_license: '1'
language:
- iso: eng
month: '06'
oa: 1
oa_version: Published Version
page: '86'
publication_identifier:
issn:
- 2663-337X
publication_status: published
publisher: Institute of Science and Technology Austria
publist_id: '6810'
pubrep_id: '828'
related_material:
record:
- id: '2082'
relation: part_of_dissertation
status: public
- id: '6196'
relation: part_of_dissertation
status: public
status: public
title: (The exact security of) Message authentication codes
type: dissertation
user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1
year: '2017'
...
---
_id: '697'
abstract:
- lang: eng
text: 'De, Trevisan and Tulsiani [CRYPTO 2010] show that every distribution over
n-bit strings which has constant statistical distance to uniform (e.g., the output
of a pseudorandom generator mapping n-1 to n bit strings), can be distinguished
from the uniform distribution with advantage epsilon by a circuit of size O( 2^n
epsilon^2). We generalize this result, showing that a distribution which has less
than k bits of min-entropy, can be distinguished from any distribution with k
bits of delta-smooth min-entropy with advantage epsilon by a circuit of size O(2^k
epsilon^2/delta^2). As a special case, this implies that any distribution with
support at most 2^k (e.g., the output of a pseudoentropy generator mapping k to
n bit strings) can be distinguished from any given distribution with min-entropy
k+1 with advantage epsilon by a circuit of size O(2^k epsilon^2). Our result thus
shows that pseudoentropy distributions face basically the same non-uniform attacks
as pseudorandom distributions. '
alternative_title:
- LIPIcs
article_number: '39'
author:
- first_name: Krzysztof Z
full_name: Pietrzak, Krzysztof Z
id: 3E04A7AA-F248-11E8-B48F-1D18A9856A87
last_name: Pietrzak
orcid: 0000-0002-9139-1654
- first_name: Maciej
full_name: Skórski, Maciej
id: EC09FA6A-02D0-11E9-8223-86B7C91467DD
last_name: Skórski
citation:
ama: 'Pietrzak KZ, Skórski M. Non uniform attacks against pseudoentropy. In: Vol
80. Schloss Dagstuhl - Leibniz-Zentrum für Informatik; 2017. doi:10.4230/LIPIcs.ICALP.2017.39'
apa: 'Pietrzak, K. Z., & Skórski, M. (2017). Non uniform attacks against pseudoentropy
(Vol. 80). Presented at the ICALP: International Colloquium on Automata, Languages,
and Programming, Warsaw, Poland: Schloss Dagstuhl - Leibniz-Zentrum für Informatik.
https://doi.org/10.4230/LIPIcs.ICALP.2017.39'
chicago: Pietrzak, Krzysztof Z, and Maciej Skórski. “Non Uniform Attacks against
Pseudoentropy,” Vol. 80. Schloss Dagstuhl - Leibniz-Zentrum für Informatik, 2017.
https://doi.org/10.4230/LIPIcs.ICALP.2017.39.
ieee: 'K. Z. Pietrzak and M. Skórski, “Non uniform attacks against pseudoentropy,”
presented at the ICALP: International Colloquium on Automata, Languages, and Programming,
Warsaw, Poland, 2017, vol. 80.'
ista: 'Pietrzak KZ, Skórski M. 2017. Non uniform attacks against pseudoentropy.
ICALP: International Colloquium on Automata, Languages, and Programming, LIPIcs,
vol. 80, 39.'
mla: Pietrzak, Krzysztof Z., and Maciej Skórski. Non Uniform Attacks against
Pseudoentropy. Vol. 80, 39, Schloss Dagstuhl - Leibniz-Zentrum für Informatik,
2017, doi:10.4230/LIPIcs.ICALP.2017.39.
short: K.Z. Pietrzak, M. Skórski, in:, Schloss Dagstuhl - Leibniz-Zentrum für Informatik,
2017.
conference:
end_date: 2017-07-14
location: Warsaw, Poland
name: 'ICALP: International Colloquium on Automata, Languages, and Programming'
start_date: 2017-07-10
date_created: 2018-12-11T11:47:59Z
date_published: 2017-07-01T00:00:00Z
date_updated: 2021-01-12T08:11:15Z
day: '01'
ddc:
- '005'
department:
- _id: KrPi
doi: 10.4230/LIPIcs.ICALP.2017.39
ec_funded: 1
file:
- access_level: open_access
checksum: e95618a001692f1af2d68f5fde43bc1f
content_type: application/pdf
creator: system
date_created: 2018-12-12T10:08:40Z
date_updated: 2020-07-14T12:47:46Z
file_id: '4701'
file_name: IST-2017-893-v1+1_LIPIcs-ICALP-2017-39.pdf
file_size: 601004
relation: main_file
file_date_updated: 2020-07-14T12:47:46Z
has_accepted_license: '1'
intvolume: ' 80'
language:
- iso: eng
month: '07'
oa: 1
oa_version: Published Version
project:
- _id: 258AA5B2-B435-11E9-9278-68D0E5697425
call_identifier: H2020
grant_number: '682815'
name: Teaching Old Crypto New Tricks
publication_identifier:
issn:
- '18688969'
publication_status: published
publisher: Schloss Dagstuhl - Leibniz-Zentrum für Informatik
publist_id: '7003'
pubrep_id: '893'
quality_controlled: '1'
scopus_import: 1
status: public
title: Non uniform attacks against pseudoentropy
tmp:
image: /images/cc_by.png
legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
short: CC BY (4.0)
type: conference
user_id: 3E5EF7F0-F248-11E8-B48F-1D18A9856A87
volume: 80
year: '2017'
...
---
_id: '710'
abstract:
- lang: eng
text: 'We revisit the problem of estimating entropy of discrete distributions from
independent samples, studied recently by Acharya, Orlitsky, Suresh and Tyagi (SODA
2015), improving their upper and lower bounds on the necessary sample size n.
For estimating Renyi entropy of order alpha, up to constant accuracy and error
probability, we show the following * Upper bounds n = O(1) 2^{(1-1/alpha)H_alpha}
for integer alpha>1, as the worst case over distributions with Renyi entropy
equal to H_alpha. * Lower bounds n = Omega(1) K^{1-1/alpha} for any real alpha>1,
with the constant being an inverse polynomial of the accuracy, as the worst case
over all distributions on K elements. Our upper bounds essentially replace the
alphabet size by a factor exponential in the entropy, which offers improvements
especially in low or medium entropy regimes (interesting for example in anomaly
detection). As for the lower bounds, our proof explicitly shows how the complexity
depends on both alphabet and accuracy, partially solving the open problem posted
in previous works. The argument for upper bounds derives a clean identity for
the variance of falling-power sum of a multinomial distribution. Our approach
for lower bounds utilizes convex optimization to find a distribution with possibly
worse estimation performance, and may be of independent interest as a tool to
work with Le Cam’s two point method. '
alternative_title:
- LIPIcs
article_number: '20'
author:
- first_name: Maciej
full_name: Obremski, Maciej
last_name: Obremski
- first_name: Maciej
full_name: Skórski, Maciej
id: EC09FA6A-02D0-11E9-8223-86B7C91467DD
last_name: Skórski
citation:
ama: 'Obremski M, Skórski M. Renyi entropy estimation revisited. In: Vol 81. Schloss
Dagstuhl - Leibniz-Zentrum für Informatik; 2017. doi:10.4230/LIPIcs.APPROX-RANDOM.2017.20'
apa: 'Obremski, M., & Skórski, M. (2017). Renyi entropy estimation revisited
(Vol. 81). Presented at the 20th International Workshop on Approximation Algorithms
for Combinatorial Optimization Problems, APPROX, Berkeley, USA: Schloss Dagstuhl
- Leibniz-Zentrum für Informatik. https://doi.org/10.4230/LIPIcs.APPROX-RANDOM.2017.20'
chicago: Obremski, Maciej, and Maciej Skórski. “Renyi Entropy Estimation Revisited,”
Vol. 81. Schloss Dagstuhl - Leibniz-Zentrum für Informatik, 2017. https://doi.org/10.4230/LIPIcs.APPROX-RANDOM.2017.20.
ieee: M. Obremski and M. Skórski, “Renyi entropy estimation revisited,” presented
at the 20th International Workshop on Approximation Algorithms for Combinatorial
Optimization Problems, APPROX, Berkeley, USA, 2017, vol. 81.
ista: Obremski M, Skórski M. 2017. Renyi entropy estimation revisited. 20th International
Workshop on Approximation Algorithms for Combinatorial Optimization Problems,
APPROX, LIPIcs, vol. 81, 20.
mla: Obremski, Maciej, and Maciej Skórski. Renyi Entropy Estimation Revisited.
Vol. 81, 20, Schloss Dagstuhl - Leibniz-Zentrum für Informatik, 2017, doi:10.4230/LIPIcs.APPROX-RANDOM.2017.20.
short: M. Obremski, M. Skórski, in:, Schloss Dagstuhl - Leibniz-Zentrum für Informatik,
2017.
conference:
end_date: 2017-08-18
location: Berkeley, USA
name: 20th International Workshop on Approximation Algorithms for Combinatorial
Optimization Problems, APPROX
start_date: 2017-08-18
date_created: 2018-12-11T11:48:04Z
date_published: 2017-08-01T00:00:00Z
date_updated: 2021-01-12T08:11:50Z
day: '01'
ddc:
- '005'
- '600'
department:
- _id: KrPi
doi: 10.4230/LIPIcs.APPROX-RANDOM.2017.20
ec_funded: 1
file:
- access_level: open_access
checksum: 89225c7dcec2c93838458c9102858985
content_type: application/pdf
creator: system
date_created: 2018-12-12T10:13:10Z
date_updated: 2020-07-14T12:47:49Z
file_id: '4991'
file_name: IST-2017-888-v1+1_LIPIcs-APPROX-RANDOM-2017-20.pdf
file_size: 604813
relation: main_file
file_date_updated: 2020-07-14T12:47:49Z
has_accepted_license: '1'
intvolume: ' 81'
language:
- iso: eng
month: '08'
oa: 1
oa_version: Published Version
project:
- _id: 258AA5B2-B435-11E9-9278-68D0E5697425
call_identifier: H2020
grant_number: '682815'
name: Teaching Old Crypto New Tricks
publication_identifier:
issn:
- '18688969'
publication_status: published
publisher: Schloss Dagstuhl - Leibniz-Zentrum für Informatik
publist_id: '6979'
pubrep_id: '888'
quality_controlled: '1'
scopus_import: 1
status: public
title: Renyi entropy estimation revisited
tmp:
image: /images/cc_by.png
legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
short: CC BY (4.0)
type: conference
user_id: 3E5EF7F0-F248-11E8-B48F-1D18A9856A87
volume: 81
year: '2017'
...
---
_id: '559'
abstract:
- lang: eng
text: 'Proofs of space (PoS) were suggested as more ecological and economical alternative
to proofs of work, which are currently used in blockchain designs like Bitcoin.
The existing PoS are based on rather sophisticated graph pebbling lower bounds.
Much simpler and in several aspects more efficient schemes based on inverting
random functions have been suggested, but they don’t give meaningful security
guarantees due to existing time-memory trade-offs. In particular, Hellman showed
that any permutation over a domain of size N can be inverted in time T by an algorithm
that is given S bits of auxiliary information whenever (Formula presented). For
functions Hellman gives a weaker attack with S2· T≈ N2 (e.g., S= T≈ N2/3). To
prove lower bounds, one considers an adversary who has access to an oracle f:
[ N] → [N] and can make T oracle queries. The best known lower bound is S· T∈
Ω(N) and holds for random functions and permutations. We construct functions that
provably require more time and/or space to invert. Specifically, for any constant
k we construct a function [N] → [N] that cannot be inverted unless Sk· T∈ Ω(Nk)
(in particular, S= T≈ (Formula presented). Our construction does not contradict
Hellman’s time-memory trade-off, because it cannot be efficiently evaluated in
forward direction. However, its entire function table can be computed in time
quasilinear in N, which is sufficient for the PoS application. Our simplest construction
is built from a random function oracle g: [N] × [N] → [ N] and a random permutation
oracle f: [N] → N] and is defined as h(x) = g(x, x′) where f(x) = π(f(x′)) with
π being any involution without a fixed point, e.g. flipping all the bits. For
this function we prove that any adversary who gets S bits of auxiliary information,
makes at most T oracle queries, and inverts h on an ϵ fraction of outputs must
satisfy S2· T∈ Ω(ϵ2N2).'
alternative_title:
- LNCS
author:
- first_name: Hamza M
full_name: Abusalah, Hamza M
id: 40297222-F248-11E8-B48F-1D18A9856A87
last_name: Abusalah
- first_name: Joel F
full_name: Alwen, Joel F
id: 2A8DFA8C-F248-11E8-B48F-1D18A9856A87
last_name: Alwen
- first_name: Bram
full_name: Cohen, Bram
last_name: Cohen
- first_name: Danylo
full_name: Khilko, Danylo
last_name: Khilko
- first_name: Krzysztof Z
full_name: Pietrzak, Krzysztof Z
id: 3E04A7AA-F248-11E8-B48F-1D18A9856A87
last_name: Pietrzak
orcid: 0000-0002-9139-1654
- first_name: Leonid
full_name: Reyzin, Leonid
last_name: Reyzin
citation:
ama: 'Abusalah HM, Alwen JF, Cohen B, Khilko D, Pietrzak KZ, Reyzin L. Beyond Hellman’s
time-memory trade-offs with applications to proofs of space. In: Vol 10625. Springer;
2017:357-379. doi:10.1007/978-3-319-70697-9_13'
apa: 'Abusalah, H. M., Alwen, J. F., Cohen, B., Khilko, D., Pietrzak, K. Z., &
Reyzin, L. (2017). Beyond Hellman’s time-memory trade-offs with applications to
proofs of space (Vol. 10625, pp. 357–379). Presented at the ASIACRYPT: Theory
and Applications of Cryptology and Information Security, Hong Kong, China: Springer.
https://doi.org/10.1007/978-3-319-70697-9_13'
chicago: Abusalah, Hamza M, Joel F Alwen, Bram Cohen, Danylo Khilko, Krzysztof Z
Pietrzak, and Leonid Reyzin. “Beyond Hellman’s Time-Memory Trade-Offs with Applications
to Proofs of Space,” 10625:357–79. Springer, 2017. https://doi.org/10.1007/978-3-319-70697-9_13.
ieee: 'H. M. Abusalah, J. F. Alwen, B. Cohen, D. Khilko, K. Z. Pietrzak, and L.
Reyzin, “Beyond Hellman’s time-memory trade-offs with applications to proofs of
space,” presented at the ASIACRYPT: Theory and Applications of Cryptology and
Information Security, Hong Kong, China, 2017, vol. 10625, pp. 357–379.'
ista: 'Abusalah HM, Alwen JF, Cohen B, Khilko D, Pietrzak KZ, Reyzin L. 2017. Beyond
Hellman’s time-memory trade-offs with applications to proofs of space. ASIACRYPT:
Theory and Applications of Cryptology and Information Security, LNCS, vol. 10625,
357–379.'
mla: Abusalah, Hamza M., et al. Beyond Hellman’s Time-Memory Trade-Offs with
Applications to Proofs of Space. Vol. 10625, Springer, 2017, pp. 357–79, doi:10.1007/978-3-319-70697-9_13.
short: H.M. Abusalah, J.F. Alwen, B. Cohen, D. Khilko, K.Z. Pietrzak, L. Reyzin,
in:, Springer, 2017, pp. 357–379.
conference:
end_date: 2017-12-07
location: Hong Kong, China
name: 'ASIACRYPT: Theory and Applications of Cryptology and Information Security'
start_date: 2017-12-03
date_created: 2018-12-11T11:47:10Z
date_published: 2017-11-18T00:00:00Z
date_updated: 2023-09-07T12:30:22Z
day: '18'
department:
- _id: KrPi
doi: 10.1007/978-3-319-70697-9_13
ec_funded: 1
intvolume: ' 10625'
language:
- iso: eng
main_file_link:
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url: https://eprint.iacr.org/2017/893.pdf
month: '11'
oa: 1
oa_version: Submitted Version
page: 357 - 379
project:
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call_identifier: H2020
grant_number: '682815'
name: Teaching Old Crypto New Tricks
publication_identifier:
isbn:
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publication_status: published
publisher: Springer
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relation: dissertation_contains
status: public
scopus_import: 1
status: public
title: Beyond Hellman’s time-memory trade-offs with applications to proofs of space
type: conference
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 10625
year: '2017'
...