---
_id: '1231'
abstract:
- lang: eng
text: 'We study the time-and memory-complexities of the problem of computing labels
of (multiple) randomly selected challenge-nodes in a directed acyclic graph. The
w-bit label of a node is the hash of the labels of its parents, and the hash function
is modeled as a random oracle. Specific instances of this problem underlie both
proofs of space [Dziembowski et al. CRYPTO’15] as well as popular memory-hard
functions like scrypt. As our main tool, we introduce the new notion of a probabilistic
parallel entangled pebbling game, a new type of combinatorial pebbling game on
a graph, which is closely related to the labeling game on the same graph. As a
first application of our framework, we prove that for scrypt, when the underlying
hash function is invoked n times, the cumulative memory complexity (CMC) (a notion
recently introduced by Alwen and Serbinenko (STOC’15) to capture amortized memory-hardness
for parallel adversaries) is at least Ω(w · (n/ log(n))2). This bound holds for
adversaries that can store many natural functions of the labels (e.g., linear
combinations), but still not arbitrary functions thereof. We then introduce and
study a combinatorial quantity, and show how a sufficiently small upper bound
on it (which we conjecture) extends our CMC bound for scrypt to hold against arbitrary
adversaries. We also show that such an upper bound solves the main open problem
for proofs-of-space protocols: namely, establishing that the time complexity of
computing the label of a random node in a graph on n nodes (given an initial kw-bit
state) reduces tightly to the time complexity for black pebbling on the same graph
(given an initial k-node pebbling).'
acknowledgement: "Joël Alwen, Chethan Kamath, and Krzysztof Pietrzak’s research is
partially supported by an ERC starting grant (259668-PSPC). Vladimir Kolmogorov
is partially supported by an ERC consolidator grant (616160-DOICV). Binyi Chen was
partially supported by NSF grants CNS-1423566 and CNS-1514526, and a gift from the
Gareatis Foundation. Stefano Tessaro was partially supported by NSF grants CNS-1423566,
CNS-1528178, a Hellman Fellowship, and the Glen and Susanne Culler Chair.\r\n\r\nThis
work was done in part while the authors were visiting the Simons Institute for the
Theory of Computing, supported by the Simons Foundation and by the DIMACS/Simons
Collaboration in Cryptography through NSF grant CNS-1523467."
alternative_title:
- LNCS
author:
- first_name: Joel F
full_name: Alwen, Joel F
id: 2A8DFA8C-F248-11E8-B48F-1D18A9856A87
last_name: Alwen
- first_name: Binyi
full_name: Chen, Binyi
last_name: Chen
- first_name: Chethan
full_name: Kamath Hosdurg, Chethan
id: 4BD3F30E-F248-11E8-B48F-1D18A9856A87
last_name: Kamath Hosdurg
- first_name: Vladimir
full_name: Kolmogorov, Vladimir
id: 3D50B0BA-F248-11E8-B48F-1D18A9856A87
last_name: Kolmogorov
- 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: Stefano
full_name: Tessaro, Stefano
last_name: Tessaro
citation:
ama: 'Alwen JF, Chen B, Kamath Hosdurg C, Kolmogorov V, Pietrzak KZ, Tessaro S.
On the complexity of scrypt and proofs of space in the parallel random oracle
model. In: Vol 9666. Springer; 2016:358-387. doi:10.1007/978-3-662-49896-5_13'
apa: 'Alwen, J. F., Chen, B., Kamath Hosdurg, C., Kolmogorov, V., Pietrzak, K. Z.,
& Tessaro, S. (2016). On the complexity of scrypt and proofs of space in the
parallel random oracle model (Vol. 9666, pp. 358–387). Presented at the EUROCRYPT:
Theory and Applications of Cryptographic Techniques, Vienna, Austria: Springer.
https://doi.org/10.1007/978-3-662-49896-5_13'
chicago: Alwen, Joel F, Binyi Chen, Chethan Kamath Hosdurg, Vladimir Kolmogorov,
Krzysztof Z Pietrzak, and Stefano Tessaro. “On the Complexity of Scrypt and Proofs
of Space in the Parallel Random Oracle Model,” 9666:358–87. Springer, 2016. https://doi.org/10.1007/978-3-662-49896-5_13.
ieee: 'J. F. Alwen, B. Chen, C. Kamath Hosdurg, V. Kolmogorov, K. Z. Pietrzak, and
S. Tessaro, “On the complexity of scrypt and proofs of space in the parallel random
oracle model,” presented at the EUROCRYPT: Theory and Applications of Cryptographic
Techniques, Vienna, Austria, 2016, vol. 9666, pp. 358–387.'
ista: 'Alwen JF, Chen B, Kamath Hosdurg C, Kolmogorov V, Pietrzak KZ, Tessaro S.
2016. On the complexity of scrypt and proofs of space in the parallel random oracle
model. EUROCRYPT: Theory and Applications of Cryptographic Techniques, LNCS, vol.
9666, 358–387.'
mla: Alwen, Joel F., et al. On the Complexity of Scrypt and Proofs of Space in
the Parallel Random Oracle Model. Vol. 9666, Springer, 2016, pp. 358–87, doi:10.1007/978-3-662-49896-5_13.
short: J.F. Alwen, B. Chen, C. Kamath Hosdurg, V. Kolmogorov, K.Z. Pietrzak, S.
Tessaro, in:, Springer, 2016, pp. 358–387.
conference:
end_date: 2016-05-12
location: Vienna, Austria
name: 'EUROCRYPT: Theory and Applications of Cryptographic Techniques'
start_date: 2016-05-08
date_created: 2018-12-11T11:50:51Z
date_published: 2016-04-28T00:00:00Z
date_updated: 2021-01-12T06:49:15Z
day: '28'
department:
- _id: KrPi
- _id: VlKo
doi: 10.1007/978-3-662-49896-5_13
ec_funded: 1
intvolume: ' 9666'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://eprint.iacr.org/2016/100
month: '04'
oa: 1
oa_version: Submitted Version
page: 358 - 387
project:
- _id: 258C570E-B435-11E9-9278-68D0E5697425
call_identifier: FP7
grant_number: '259668'
name: Provable Security for Physical Cryptography
- _id: 25FBA906-B435-11E9-9278-68D0E5697425
call_identifier: FP7
grant_number: '616160'
name: 'Discrete Optimization in Computer Vision: Theory and Practice'
publication_status: published
publisher: Springer
publist_id: '6103'
quality_controlled: '1'
scopus_import: 1
status: public
title: On the complexity of scrypt and proofs of space in the parallel random oracle
model
type: conference
user_id: 3E5EF7F0-F248-11E8-B48F-1D18A9856A87
volume: 9666
year: '2016'
...
---
_id: '1233'
abstract:
- lang: eng
text: About three decades ago it was realized that implementing private channels
between parties which can be adaptively corrupted requires an encryption scheme
that is secure against selective opening attacks. Whether standard (IND-CPA) security
implies security against selective opening attacks has been a major open question
since. The only known reduction from selective opening to IND-CPA security loses
an exponential factor. A polynomial reduction is only known for the very special
case where the distribution considered in the selective opening security experiment
is a product distribution, i.e., the messages are sampled independently from each
other. In this paper we give a reduction whose loss is quantified via the dependence
graph (where message dependencies correspond to edges) of the underlying message
distribution. In particular, for some concrete distributions including Markov
distributions, our reduction is polynomial.
acknowledgement: G. Fuchsbauer and K. Pietrzak are supported by the European Research
Council, ERC Starting Grant (259668-PSPC). F. Heuer is funded by a Sofja Kovalevskaja
Award of the Alexander von Humboldt Foundation and DFG SPP 1736, Algorithms for
BIG DATA. E. Kiltz is supported by a Sofja Kovalevskaja Award of the Alexander von
Humboldt Foundation, the German Israel Foundation, and ERC Project ERCC (FP7/615074).
alternative_title:
- LNCS
author:
- first_name: Georg
full_name: Fuchsbauer, Georg
id: 46B4C3EE-F248-11E8-B48F-1D18A9856A87
last_name: Fuchsbauer
- first_name: Felix
full_name: Heuer, Felix
last_name: Heuer
- first_name: Eike
full_name: Kiltz, Eike
last_name: Kiltz
- 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, Heuer F, Kiltz E, Pietrzak KZ. Standard security does imply
security against selective opening for markov distributions. In: Vol 9562. Springer;
2016:282-305. doi:10.1007/978-3-662-49096-9_12'
apa: 'Fuchsbauer, G., Heuer, F., Kiltz, E., & Pietrzak, K. Z. (2016). Standard
security does imply security against selective opening for markov distributions
(Vol. 9562, pp. 282–305). Presented at the TCC: Theory of Cryptography Conference,
Tel Aviv, Israel: Springer. https://doi.org/10.1007/978-3-662-49096-9_12'
chicago: Fuchsbauer, Georg, Felix Heuer, Eike Kiltz, and Krzysztof Z Pietrzak. “Standard
Security Does Imply Security against Selective Opening for Markov Distributions,”
9562:282–305. Springer, 2016. https://doi.org/10.1007/978-3-662-49096-9_12.
ieee: 'G. Fuchsbauer, F. Heuer, E. Kiltz, and K. Z. Pietrzak, “Standard security
does imply security against selective opening for markov distributions,” presented
at the TCC: Theory of Cryptography Conference, Tel Aviv, Israel, 2016, vol. 9562,
pp. 282–305.'
ista: 'Fuchsbauer G, Heuer F, Kiltz E, Pietrzak KZ. 2016. Standard security does
imply security against selective opening for markov distributions. TCC: Theory
of Cryptography Conference, LNCS, vol. 9562, 282–305.'
mla: Fuchsbauer, Georg, et al. Standard Security Does Imply Security against
Selective Opening for Markov Distributions. Vol. 9562, Springer, 2016, pp.
282–305, doi:10.1007/978-3-662-49096-9_12.
short: G. Fuchsbauer, F. Heuer, E. Kiltz, K.Z. Pietrzak, in:, Springer, 2016, pp.
282–305.
conference:
end_date: 2016-01-13
location: Tel Aviv, Israel
name: 'TCC: Theory of Cryptography Conference'
start_date: 2016-01-10
date_created: 2018-12-11T11:50:51Z
date_published: 2016-01-01T00:00:00Z
date_updated: 2021-01-12T06:49:16Z
day: '01'
department:
- _id: KrPi
doi: 10.1007/978-3-662-49096-9_12
ec_funded: 1
intvolume: ' 9562'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://eprint.iacr.org/2015/853
month: '01'
oa: 1
oa_version: Submitted Version
page: 282 - 305
project:
- _id: 258C570E-B435-11E9-9278-68D0E5697425
call_identifier: FP7
grant_number: '259668'
name: Provable Security for Physical Cryptography
publication_status: published
publisher: Springer
publist_id: '6100'
quality_controlled: '1'
scopus_import: 1
status: public
title: Standard security does imply security against selective opening for markov
distributions
type: conference
user_id: 3E5EF7F0-F248-11E8-B48F-1D18A9856A87
volume: 9562
year: '2016'
...
---
_id: '1235'
abstract:
- lang: eng
text: 'A constrained pseudorandom function (CPRF) F: K×X → Y for a family T of subsets
of χ is a function where for any key k ∈ K and set S ∈ T one can efficiently compute
a short constrained key kS, which allows to evaluate F(k, ·) on all inputs x ∈
S, while the outputs on all inputs x /∈ S look random even given kS. Abusalah
et al. recently constructed the first constrained PRF for inputs of arbitrary
length whose sets S are decided by Turing machines. They use their CPRF to build
broadcast encryption and the first ID-based non-interactive key exchange for an
unbounded number of users. Their constrained keys are obfuscated circuits and
are therefore large. In this work we drastically reduce the key size and define
a constrained key for a Turing machine M as a short signature on M. For this,
we introduce a new signature primitive with constrained signing keys that let
one only sign certain messages, while forging a signature on others is hard even
when knowing the coins for key generation.'
acknowledgement: H. Abusalah—Research supported by the European Research Council,
ERC starting grant (259668-PSPC) and ERC consolidator grant (682815 - TOCNeT).
alternative_title:
- LNCS
author:
- first_name: Hamza M
full_name: Abusalah, Hamza M
id: 40297222-F248-11E8-B48F-1D18A9856A87
last_name: Abusalah
- first_name: Georg
full_name: Fuchsbauer, Georg
id: 46B4C3EE-F248-11E8-B48F-1D18A9856A87
last_name: Fuchsbauer
citation:
ama: 'Abusalah HM, Fuchsbauer G. Constrained PRFs for unbounded inputs with short
keys. In: Vol 9696. Springer; 2016:445-463. doi:10.1007/978-3-319-39555-5_24'
apa: 'Abusalah, H. M., & Fuchsbauer, G. (2016). Constrained PRFs for unbounded
inputs with short keys (Vol. 9696, pp. 445–463). Presented at the ACNS: Applied
Cryptography and Network Security, Guildford, UK: Springer. https://doi.org/10.1007/978-3-319-39555-5_24'
chicago: Abusalah, Hamza M, and Georg Fuchsbauer. “Constrained PRFs for Unbounded
Inputs with Short Keys,” 9696:445–63. Springer, 2016. https://doi.org/10.1007/978-3-319-39555-5_24.
ieee: 'H. M. Abusalah and G. Fuchsbauer, “Constrained PRFs for unbounded inputs
with short keys,” presented at the ACNS: Applied Cryptography and Network Security,
Guildford, UK, 2016, vol. 9696, pp. 445–463.'
ista: 'Abusalah HM, Fuchsbauer G. 2016. Constrained PRFs for unbounded inputs with
short keys. ACNS: Applied Cryptography and Network Security, LNCS, vol. 9696,
445–463.'
mla: Abusalah, Hamza M., and Georg Fuchsbauer. Constrained PRFs for Unbounded
Inputs with Short Keys. Vol. 9696, Springer, 2016, pp. 445–63, doi:10.1007/978-3-319-39555-5_24.
short: H.M. Abusalah, G. Fuchsbauer, in:, Springer, 2016, pp. 445–463.
conference:
end_date: 2016-06-22
location: Guildford, UK
name: 'ACNS: Applied Cryptography and Network Security'
start_date: 2016-06-19
date_created: 2018-12-11T11:50:52Z
date_published: 2016-01-01T00:00:00Z
date_updated: 2023-09-07T12:30:22Z
day: '01'
department:
- _id: KrPi
doi: 10.1007/978-3-319-39555-5_24
ec_funded: 1
intvolume: ' 9696'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://eprint.iacr.org/2016/279.pdf
month: '01'
oa: 1
oa_version: Submitted Version
page: 445 - 463
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_status: published
publisher: Springer
publist_id: '6098'
quality_controlled: '1'
related_material:
record:
- id: '83'
relation: dissertation_contains
status: public
scopus_import: 1
status: public
title: Constrained PRFs for unbounded inputs with short keys
type: conference
user_id: 3E5EF7F0-F248-11E8-B48F-1D18A9856A87
volume: 9696
year: '2016'
...
---
_id: '1236'
abstract:
- lang: eng
text: 'A constrained pseudorandom function F: K × X → Y for a family T ⊆ 2X of subsets
of X is a function where for any key k ∈ K and set S ∈ T one can efficiently compute
a constrained key kS which allows to evaluate F (k, ·) on all inputs x ∈ S, while
even given this key, the outputs on all inputs x ∉ S look random. At Asiacrypt’13
Boneh and Waters gave a construction which supports the most general set family
so far. Its keys kc are defined for sets decided by boolean circuits C and enable
evaluation of the PRF on any x ∈ X where C(x) = 1. In their construction the PRF
input length and the size of the circuits C for which constrained keys can be
computed must be fixed beforehand during key generation. We construct a constrained
PRF that has an unbounded input length and whose constrained keys can be defined
for any set recognized by a Turing machine. The only a priori bound we make is
on the description size of the machines. We prove our construction secure assuming
publiccoin differing-input obfuscation. As applications of our constrained PRF
we build a broadcast encryption scheme where the number of potential receivers
need not be fixed at setup (in particular, the length of the keys is independent
of the number of parties) and the first identity-based non-interactive key exchange
protocol with no bound on the number of parties that can agree on a shared key.'
acknowledgement: Supported by the European Research Council, ERC Starting Grant (259668-PSPC).
alternative_title:
- LNCS
author:
- first_name: Hamza M
full_name: Abusalah, Hamza M
id: 40297222-F248-11E8-B48F-1D18A9856A87
last_name: Abusalah
- first_name: Georg
full_name: Fuchsbauer, Georg
id: 46B4C3EE-F248-11E8-B48F-1D18A9856A87
last_name: Fuchsbauer
- 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: 'Abusalah HM, Fuchsbauer G, Pietrzak KZ. Constrained PRFs for unbounded inputs.
In: Vol 9610. Springer; 2016:413-428. doi:10.1007/978-3-319-29485-8_24'
apa: 'Abusalah, H. M., Fuchsbauer, G., & Pietrzak, K. Z. (2016). Constrained
PRFs for unbounded inputs (Vol. 9610, pp. 413–428). Presented at the CT-RSA: Topics
in Cryptology, San Francisco, CA, USA: Springer. https://doi.org/10.1007/978-3-319-29485-8_24'
chicago: Abusalah, Hamza M, Georg Fuchsbauer, and Krzysztof Z Pietrzak. “Constrained
PRFs for Unbounded Inputs,” 9610:413–28. Springer, 2016. https://doi.org/10.1007/978-3-319-29485-8_24.
ieee: 'H. M. Abusalah, G. Fuchsbauer, and K. Z. Pietrzak, “Constrained PRFs for
unbounded inputs,” presented at the CT-RSA: Topics in Cryptology, San Francisco,
CA, USA, 2016, vol. 9610, pp. 413–428.'
ista: 'Abusalah HM, Fuchsbauer G, Pietrzak KZ. 2016. Constrained PRFs for unbounded
inputs. CT-RSA: Topics in Cryptology, LNCS, vol. 9610, 413–428.'
mla: Abusalah, Hamza M., et al. Constrained PRFs for Unbounded Inputs. Vol.
9610, Springer, 2016, pp. 413–28, doi:10.1007/978-3-319-29485-8_24.
short: H.M. Abusalah, G. Fuchsbauer, K.Z. Pietrzak, in:, Springer, 2016, pp. 413–428.
conference:
end_date: 2016-03-04
location: San Francisco, CA, USA
name: 'CT-RSA: Topics in Cryptology'
start_date: 2016-02-29
date_created: 2018-12-11T11:50:52Z
date_published: 2016-02-02T00:00:00Z
date_updated: 2023-09-07T12:30:22Z
day: '02'
ddc:
- '005'
- '600'
department:
- _id: KrPi
doi: 10.1007/978-3-319-29485-8_24
ec_funded: 1
file:
- access_level: open_access
checksum: 3851cee49933ae13b1272e516f213e13
content_type: application/pdf
creator: system
date_created: 2018-12-12T10:08:05Z
date_updated: 2020-07-14T12:44:41Z
file_id: '4664'
file_name: IST-2017-764-v1+1_279.pdf
file_size: 495176
relation: main_file
file_date_updated: 2020-07-14T12:44:41Z
has_accepted_license: '1'
intvolume: ' 9610'
language:
- iso: eng
month: '02'
oa: 1
oa_version: Submitted Version
page: 413 - 428
project:
- _id: 258C570E-B435-11E9-9278-68D0E5697425
call_identifier: FP7
grant_number: '259668'
name: Provable Security for Physical Cryptography
publication_status: published
publisher: Springer
publist_id: '6097'
pubrep_id: '764'
quality_controlled: '1'
related_material:
record:
- id: '83'
relation: dissertation_contains
status: public
scopus_import: 1
status: public
title: Constrained PRFs for unbounded inputs
type: conference
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 9610
year: '2016'
...
---
_id: '1644'
abstract:
- lang: eng
text: Increasing the computational complexity of evaluating a hash function, both
for the honest users as well as for an adversary, is a useful technique employed
for example in password-based cryptographic schemes to impede brute-force attacks,
and also in so-called proofs of work (used in protocols like Bitcoin) to show
that a certain amount of computation was performed by a legitimate user. A natural
approach to adjust the complexity of a hash function is to iterate it c times,
for some parameter c, in the hope that any query to the scheme requires c evaluations
of the underlying hash function. However, results by Dodis et al. (Crypto 2012)
imply that plain iteration falls short of achieving this goal, and designing schemes
which provably have such a desirable property remained an open problem. This paper
formalizes explicitly what it means for a given scheme to amplify the query complexity
of a hash function. In the random oracle model, the goal of a secure query-complexity
amplifier (QCA) scheme is captured as transforming, in the sense of indifferentiability,
a random oracle allowing R queries (for the adversary) into one provably allowing
only r < R queries. Turned around, this means that making r queries to the
scheme requires at least R queries to the actual random oracle. Second, a new
scheme, called collision-free iteration, is proposed and proven to achieve c-fold
QCA for both the honest parties and the adversary, for any fixed parameter c.
alternative_title:
- LNCS
author:
- first_name: Grégory
full_name: Demay, Grégory
last_name: Demay
- first_name: Peter
full_name: Gazi, Peter
id: 3E0BFE38-F248-11E8-B48F-1D18A9856A87
last_name: Gazi
- first_name: Ueli
full_name: Maurer, Ueli
last_name: Maurer
- first_name: Björn
full_name: Tackmann, Björn
last_name: Tackmann
citation:
ama: 'Demay G, Gazi P, Maurer U, Tackmann B. Query-complexity amplification for
random oracles. In: Vol 9063. Springer; 2015:159-180. doi:10.1007/978-3-319-17470-9_10'
apa: 'Demay, G., Gazi, P., Maurer, U., & Tackmann, B. (2015). Query-complexity
amplification for random oracles (Vol. 9063, pp. 159–180). Presented at the ICITS:
International Conference on Information Theoretic Security, Lugano, Switzerland:
Springer. https://doi.org/10.1007/978-3-319-17470-9_10'
chicago: Demay, Grégory, Peter Gazi, Ueli Maurer, and Björn Tackmann. “Query-Complexity
Amplification for Random Oracles,” 9063:159–80. Springer, 2015. https://doi.org/10.1007/978-3-319-17470-9_10.
ieee: 'G. Demay, P. Gazi, U. Maurer, and B. Tackmann, “Query-complexity amplification
for random oracles,” presented at the ICITS: International Conference on Information
Theoretic Security, Lugano, Switzerland, 2015, vol. 9063, pp. 159–180.'
ista: 'Demay G, Gazi P, Maurer U, Tackmann B. 2015. Query-complexity amplification
for random oracles. ICITS: International Conference on Information Theoretic Security,
LNCS, vol. 9063, 159–180.'
mla: Demay, Grégory, et al. Query-Complexity Amplification for Random Oracles.
Vol. 9063, Springer, 2015, pp. 159–80, doi:10.1007/978-3-319-17470-9_10.
short: G. Demay, P. Gazi, U. Maurer, B. Tackmann, in:, Springer, 2015, pp. 159–180.
conference:
end_date: 2015-05-05
location: Lugano, Switzerland
name: 'ICITS: International Conference on Information Theoretic Security'
start_date: 2015-05-02
date_created: 2018-12-11T11:53:13Z
date_published: 2015-01-01T00:00:00Z
date_updated: 2021-01-12T06:52:13Z
day: '01'
department:
- _id: KrPi
doi: 10.1007/978-3-319-17470-9_10
ec_funded: 1
intvolume: ' 9063'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: http://eprint.iacr.org/2015/315
month: '01'
oa: 1
oa_version: Submitted Version
page: 159 - 180
project:
- _id: 258C570E-B435-11E9-9278-68D0E5697425
call_identifier: FP7
grant_number: '259668'
name: Provable Security for Physical Cryptography
publication_status: published
publisher: Springer
publist_id: '5507'
quality_controlled: '1'
scopus_import: 1
status: public
title: Query-complexity amplification for random oracles
type: conference
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 9063
year: '2015'
...
---
_id: '1645'
abstract:
- lang: eng
text: Secret-key constructions are often proved secure in a model where one or more
underlying components are replaced by an idealized oracle accessible to the attacker.
This model gives rise to information-theoretic security analyses, and several
advances have been made in this area over the last few years. This paper provides
a systematic overview of what is achievable in this model, and how existing works
fit into this view.
article_number: '7133163'
author:
- first_name: Peter
full_name: Gazi, Peter
id: 3E0BFE38-F248-11E8-B48F-1D18A9856A87
last_name: Gazi
- first_name: Stefano
full_name: Tessaro, Stefano
last_name: Tessaro
citation:
ama: 'Gazi P, Tessaro S. Secret-key cryptography from ideal primitives: A systematic
verview. In: 2015 IEEE Information Theory Workshop. IEEE; 2015. doi:10.1109/ITW.2015.7133163'
apa: 'Gazi, P., & Tessaro, S. (2015). Secret-key cryptography from ideal primitives:
A systematic verview. In 2015 IEEE Information Theory Workshop. Jerusalem,
Israel: IEEE. https://doi.org/10.1109/ITW.2015.7133163'
chicago: 'Gazi, Peter, and Stefano Tessaro. “Secret-Key Cryptography from Ideal
Primitives: A Systematic Verview.” In 2015 IEEE Information Theory Workshop.
IEEE, 2015. https://doi.org/10.1109/ITW.2015.7133163.'
ieee: 'P. Gazi and S. Tessaro, “Secret-key cryptography from ideal primitives: A
systematic verview,” in 2015 IEEE Information Theory Workshop, Jerusalem,
Israel, 2015.'
ista: 'Gazi P, Tessaro S. 2015. Secret-key cryptography from ideal primitives: A
systematic verview. 2015 IEEE Information Theory Workshop. ITW 2015: IEEE Information
Theory Workshop, 7133163.'
mla: 'Gazi, Peter, and Stefano Tessaro. “Secret-Key Cryptography from Ideal Primitives:
A Systematic Verview.” 2015 IEEE Information Theory Workshop, 7133163,
IEEE, 2015, doi:10.1109/ITW.2015.7133163.'
short: P. Gazi, S. Tessaro, in:, 2015 IEEE Information Theory Workshop, IEEE, 2015.
conference:
end_date: 2015-05-01
location: Jerusalem, Israel
name: 'ITW 2015: IEEE Information Theory Workshop'
start_date: 2015-04-26
date_created: 2018-12-11T11:53:13Z
date_published: 2015-06-24T00:00:00Z
date_updated: 2021-01-12T06:52:13Z
day: '24'
department:
- _id: KrPi
doi: 10.1109/ITW.2015.7133163
ec_funded: 1
language:
- iso: eng
month: '06'
oa_version: None
project:
- _id: 258C570E-B435-11E9-9278-68D0E5697425
call_identifier: FP7
grant_number: '259668'
name: Provable Security for Physical Cryptography
publication: 2015 IEEE Information Theory Workshop
publication_status: published
publisher: IEEE
publist_id: '5506'
quality_controlled: '1'
scopus_import: 1
status: public
title: 'Secret-key cryptography from ideal primitives: A systematic verview'
type: conference
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
year: '2015'
...
---
_id: '1646'
abstract:
- lang: eng
text: 'A pseudorandom function (PRF) is a keyed function F : K × X → Y where, for
a random key k ∈ K, the function F(k, ·) is indistinguishable from a uniformly
random function, given black-box access. A key-homomorphic PRF has the additional
feature that for any keys k, k'' and any input x, we have F(k+k'', x) = F(k, x)⊕F(k'',
x) for some group operations +,⊕ on K and Y, respectively. A constrained PRF for
a family of setsS ⊆ P(X) has the property that, given any key k and set S ∈ S,
one can efficiently compute a “constrained” key kS that enables evaluation of
F(k, x) on all inputs x ∈ S, while the values F(k, x) for x /∈ S remain pseudorandom
even given kS. In this paper we construct PRFs that are simultaneously constrained
and key homomorphic, where the homomorphic property holds even for constrained
keys. We first show that the multilinear map-based bit-fixing and circuit-constrained
PRFs of Boneh and Waters (Asiacrypt 2013) can be modified to also be keyhomomorphic.
We then show that the LWE-based key-homomorphic PRFs of Banerjee and Peikert (Crypto
2014) are essentially already prefix-constrained PRFs, using a (non-obvious) definition
of constrained keys and associated group operation. Moreover, the constrained
keys themselves are pseudorandom, and the constraining and evaluation functions
can all be computed in low depth. As an application of key-homomorphic constrained
PRFs,we construct a proxy re-encryption schemewith fine-grained access control.
This scheme allows storing encrypted data on an untrusted server, where each file
can be encrypted relative to some attributes, so that only parties whose constrained
keys match the attributes can decrypt. Moreover, the server can re-key (arbitrary
subsets of) the ciphertexts without learning anything about the plaintexts, thus
permitting efficient and finegrained revocation.'
alternative_title:
- LNCS
article_processing_charge: No
author:
- first_name: Abishek
full_name: Banerjee, Abishek
last_name: Banerjee
- first_name: Georg
full_name: Fuchsbauer, Georg
id: 46B4C3EE-F248-11E8-B48F-1D18A9856A87
last_name: Fuchsbauer
- first_name: Chris
full_name: Peikert, Chris
last_name: Peikert
- 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: Sophie
full_name: Stevens, Sophie
last_name: Stevens
citation:
ama: 'Banerjee A, Fuchsbauer G, Peikert C, Pietrzak KZ, Stevens S. Key-homomorphic
constrained pseudorandom functions. In: 12th Theory of Cryptography Conference.
Vol 9015. Springer Nature; 2015:31-60. doi:10.1007/978-3-662-46497-7_2'
apa: 'Banerjee, A., Fuchsbauer, G., Peikert, C., Pietrzak, K. Z., & Stevens,
S. (2015). Key-homomorphic constrained pseudorandom functions. In 12th Theory
of Cryptography Conference (Vol. 9015, pp. 31–60). Warsaw, Poland: Springer
Nature. https://doi.org/10.1007/978-3-662-46497-7_2'
chicago: Banerjee, Abishek, Georg Fuchsbauer, Chris Peikert, Krzysztof Z Pietrzak,
and Sophie Stevens. “Key-Homomorphic Constrained Pseudorandom Functions.” In 12th
Theory of Cryptography Conference, 9015:31–60. Springer Nature, 2015. https://doi.org/10.1007/978-3-662-46497-7_2.
ieee: A. Banerjee, G. Fuchsbauer, C. Peikert, K. Z. Pietrzak, and S. Stevens, “Key-homomorphic
constrained pseudorandom functions,” in 12th Theory of Cryptography Conference,
Warsaw, Poland, 2015, vol. 9015, pp. 31–60.
ista: 'Banerjee A, Fuchsbauer G, Peikert C, Pietrzak KZ, Stevens S. 2015. Key-homomorphic
constrained pseudorandom functions. 12th Theory of Cryptography Conference. TCC:
Theory of Cryptography Conference, LNCS, vol. 9015, 31–60.'
mla: Banerjee, Abishek, et al. “Key-Homomorphic Constrained Pseudorandom Functions.”
12th Theory of Cryptography Conference, vol. 9015, Springer Nature, 2015,
pp. 31–60, doi:10.1007/978-3-662-46497-7_2.
short: A. Banerjee, G. Fuchsbauer, C. Peikert, K.Z. Pietrzak, S. Stevens, in:, 12th
Theory of Cryptography Conference, Springer Nature, 2015, pp. 31–60.
conference:
end_date: 2015-03-25
location: Warsaw, Poland
name: 'TCC: Theory of Cryptography Conference'
start_date: 2015-03-23
date_created: 2018-12-11T11:53:14Z
date_published: 2015-03-01T00:00:00Z
date_updated: 2022-02-03T08:41:46Z
day: '01'
ddc:
- '000'
- '004'
department:
- _id: KrPi
doi: 10.1007/978-3-662-46497-7_2
ec_funded: 1
file:
- access_level: open_access
checksum: 3c5093bda5783c89beaacabf1aa0e60e
content_type: application/pdf
creator: system
date_created: 2018-12-12T10:15:17Z
date_updated: 2020-07-14T12:45:08Z
file_id: '5136'
file_name: IST-2016-679-v1+1_180.pdf
file_size: 450665
relation: main_file
file_date_updated: 2020-07-14T12:45:08Z
has_accepted_license: '1'
intvolume: ' 9015'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://eprint.iacr.org/2015/180
month: '03'
oa: 1
oa_version: Submitted Version
page: 31 - 60
project:
- _id: 258C570E-B435-11E9-9278-68D0E5697425
call_identifier: FP7
grant_number: '259668'
name: Provable Security for Physical Cryptography
publication: 12th Theory of Cryptography Conference
publication_identifier:
isbn:
- 978-3-662-46496-0
publication_status: published
publisher: Springer Nature
publist_id: '5505'
pubrep_id: '679'
quality_controlled: '1'
scopus_import: '1'
status: public
title: Key-homomorphic constrained pseudorandom functions
type: conference
user_id: 8b945eb4-e2f2-11eb-945a-df72226e66a9
volume: 9015
year: '2015'
...
---
_id: '1647'
abstract:
- lang: eng
text: Round-optimal blind signatures are notoriously hard to construct in the standard
model, especially in the malicious-signer model, where blindness must hold under
adversarially chosen keys. This is substantiated by several impossibility results.
The only construction that can be termed theoretically efficient, by Garg and
Gupta (Eurocrypt’14), requires complexity leveraging, inducing an exponential
security loss. We present a construction of practically efficient round-optimal
blind signatures in the standard model. It is conceptually simple and builds on
the recent structure-preserving signatures on equivalence classes (SPSEQ) from
Asiacrypt’14. While the traditional notion of blindness follows from standard
assumptions, we prove blindness under adversarially chosen keys under an interactive
variant of DDH. However, we neither require non-uniform assumptions nor complexity
leveraging. We then show how to extend our construction to partially blind signatures
and to blind signatures on message vectors, which yield a construction of one-show
anonymous credentials à la “anonymous credentials light” (CCS’13) in the standard
model. Furthermore, we give the first SPS-EQ construction under noninteractive
assumptions and show how SPS-EQ schemes imply conventional structure-preserving
signatures, which allows us to apply optimality results for the latter to SPS-EQ.
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: Christian
full_name: Hanser, Christian
last_name: Hanser
- first_name: Daniel
full_name: Slamanig, Daniel
last_name: Slamanig
citation:
ama: 'Fuchsbauer G, Hanser C, Slamanig D. Practical round-optimal blind signatures
in the standard model. In: Vol 9216. Springer; 2015:233-253. doi:10.1007/978-3-662-48000-7_12'
apa: 'Fuchsbauer, G., Hanser, C., & Slamanig, D. (2015). Practical round-optimal
blind signatures in the standard model (Vol. 9216, pp. 233–253). Presented at
the CRYPTO: International Cryptology Conference, Santa Barbara, CA, United States:
Springer. https://doi.org/10.1007/978-3-662-48000-7_12'
chicago: Fuchsbauer, Georg, Christian Hanser, and Daniel Slamanig. “Practical Round-Optimal
Blind Signatures in the Standard Model,” 9216:233–53. Springer, 2015. https://doi.org/10.1007/978-3-662-48000-7_12.
ieee: 'G. Fuchsbauer, C. Hanser, and D. Slamanig, “Practical round-optimal blind
signatures in the standard model,” presented at the CRYPTO: International Cryptology
Conference, Santa Barbara, CA, United States, 2015, vol. 9216, pp. 233–253.'
ista: 'Fuchsbauer G, Hanser C, Slamanig D. 2015. Practical round-optimal blind signatures
in the standard model. CRYPTO: International Cryptology Conference, LNCS, vol.
9216, 233–253.'
mla: Fuchsbauer, Georg, et al. Practical Round-Optimal Blind Signatures in the
Standard Model. Vol. 9216, Springer, 2015, pp. 233–53, doi:10.1007/978-3-662-48000-7_12.
short: G. Fuchsbauer, C. Hanser, D. Slamanig, in:, Springer, 2015, pp. 233–253.
conference:
end_date: 2015-08-20
location: Santa Barbara, CA, United States
name: 'CRYPTO: International Cryptology Conference'
start_date: 2015-08-16
date_created: 2018-12-11T11:53:14Z
date_published: 2015-08-01T00:00:00Z
date_updated: 2023-02-21T16:44:51Z
day: '01'
department:
- _id: KrPi
doi: 10.1007/978-3-662-48000-7_12
ec_funded: 1
intvolume: ' 9216'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://eprint.iacr.org/2015/626.pdf
month: '08'
oa: 1
oa_version: Submitted Version
page: 233 - 253
project:
- _id: 258C570E-B435-11E9-9278-68D0E5697425
call_identifier: FP7
grant_number: '259668'
name: Provable Security for Physical Cryptography
publication_status: published
publisher: Springer
publist_id: '5503'
quality_controlled: '1'
related_material:
record:
- id: '1225'
relation: later_version
status: public
scopus_import: 1
status: public
title: Practical round-optimal blind signatures in the standard model
type: conference
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 9216
year: '2015'
...
---
_id: '1648'
abstract:
- lang: eng
text: Generalized Selective Decryption (GSD), introduced by Panjwani [TCC’07], is
a game for a symmetric encryption scheme Enc that captures the difficulty of proving
adaptive security of certain protocols, most notably the Logical Key Hierarchy
(LKH) multicast encryption protocol. In the GSD game there are n keys k1,...,
kn, which the adversary may adaptively corrupt (learn); moreover, it can ask for
encryptions Encki (kj) of keys under other keys. The adversary’s task is to distinguish
keys (which it cannot trivially compute) from random. Proving the hardness of
GSD assuming only IND-CPA security of Enc is surprisingly hard. Using “complexity
leveraging” loses a factor exponential in n, which makes the proof practically
meaningless. We can think of the GSD game as building a graph on n vertices, where
we add an edge i → j when the adversary asks for an encryption of kj under ki.
If restricted to graphs of depth ℓ, Panjwani gave a reduction that loses only
a factor exponential in ℓ (not n). To date, this is the only non-trivial result
known for GSD. In this paper we give almost-polynomial reductions for large classes
of graphs. Most importantly, we prove the security of the GSD game restricted
to trees losing only a quasi-polynomial factor n3 log n+5. Trees are an important
special case capturing real-world protocols like the LKH protocol. Our new bound
improves upon Panjwani’s on some LKH variants proposed in the literature where
the underlying tree is not balanced. Our proof builds on ideas from the “nested
hybrids” technique recently introduced by Fuchsbauer et al. [Asiacrypt’14] for
proving the adaptive security of constrained PRFs.
alternative_title:
- LNCS
author:
- first_name: Georg
full_name: Fuchsbauer, Georg
id: 46B4C3EE-F248-11E8-B48F-1D18A9856A87
last_name: Fuchsbauer
- first_name: Zahra
full_name: Jafargholi, Zahra
last_name: Jafargholi
- 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, Jafargholi Z, Pietrzak KZ. A quasipolynomial reduction for generalized
selective decryption on trees. In: Vol 9215. Springer; 2015:601-620. doi:10.1007/978-3-662-47989-6_29'
apa: 'Fuchsbauer, G., Jafargholi, Z., & Pietrzak, K. Z. (2015). A quasipolynomial
reduction for generalized selective decryption on trees (Vol. 9215, pp. 601–620).
Presented at the CRYPTO: International Cryptology Conference, Santa Barbara, CA,
USA: Springer. https://doi.org/10.1007/978-3-662-47989-6_29'
chicago: Fuchsbauer, Georg, Zahra Jafargholi, and Krzysztof Z Pietrzak. “A Quasipolynomial
Reduction for Generalized Selective Decryption on Trees,” 9215:601–20. Springer,
2015. https://doi.org/10.1007/978-3-662-47989-6_29.
ieee: 'G. Fuchsbauer, Z. Jafargholi, and K. Z. Pietrzak, “A quasipolynomial reduction
for generalized selective decryption on trees,” presented at the CRYPTO: International
Cryptology Conference, Santa Barbara, CA, USA, 2015, vol. 9215, pp. 601–620.'
ista: 'Fuchsbauer G, Jafargholi Z, Pietrzak KZ. 2015. A quasipolynomial reduction
for generalized selective decryption on trees. CRYPTO: International Cryptology
Conference, LNCS, vol. 9215, 601–620.'
mla: Fuchsbauer, Georg, et al. A Quasipolynomial Reduction for Generalized Selective
Decryption on Trees. Vol. 9215, Springer, 2015, pp. 601–20, doi:10.1007/978-3-662-47989-6_29.
short: G. Fuchsbauer, Z. Jafargholi, K.Z. Pietrzak, in:, Springer, 2015, pp. 601–620.
conference:
end_date: 2015-08-20
location: Santa Barbara, CA, USA
name: 'CRYPTO: International Cryptology Conference'
start_date: 2015-08-16
date_created: 2018-12-11T11:53:14Z
date_published: 2015-08-01T00:00:00Z
date_updated: 2021-01-12T06:52:14Z
day: '01'
ddc:
- '004'
department:
- _id: KrPi
doi: 10.1007/978-3-662-47989-6_29
ec_funded: 1
file:
- access_level: open_access
checksum: 99b76b3263d5082554d0a9cbdeca3a22
content_type: application/pdf
creator: system
date_created: 2018-12-12T10:13:31Z
date_updated: 2020-07-14T12:45:08Z
file_id: '5015'
file_name: IST-2016-674-v1+1_389.pdf
file_size: 505618
relation: main_file
file_date_updated: 2020-07-14T12:45:08Z
has_accepted_license: '1'
intvolume: ' 9215'
language:
- iso: eng
month: '08'
oa: 1
oa_version: Submitted Version
page: 601 - 620
project:
- _id: 258C570E-B435-11E9-9278-68D0E5697425
call_identifier: FP7
grant_number: '259668'
name: Provable Security for Physical Cryptography
publication_status: published
publisher: Springer
publist_id: '5502'
pubrep_id: '674'
quality_controlled: '1'
scopus_import: 1
status: public
title: A quasipolynomial reduction for generalized selective decryption on trees
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: 9215
year: '2015'
...
---
_id: '1649'
abstract:
- lang: eng
text: 'We extend a commitment scheme based on the learning with errors over rings
(RLWE) problem, and present efficient companion zeroknowledge proofs of knowledge.
Our scheme maps elements from the ring (or equivalently, n elements from '
alternative_title:
- LNCS
author:
- first_name: Fabrice
full_name: Benhamouda, Fabrice
last_name: Benhamouda
- first_name: Stephan
full_name: Krenn, Stephan
last_name: Krenn
- first_name: Vadim
full_name: Lyubashevsky, Vadim
last_name: Lyubashevsky
- 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: Benhamouda F, Krenn S, Lyubashevsky V, Pietrzak KZ. Efficient zero-knowledge
proofs for commitments from learning with errors over rings. 2015;9326:305-325.
doi:10.1007/978-3-319-24174-6_16
apa: 'Benhamouda, F., Krenn, S., Lyubashevsky, V., & Pietrzak, K. Z. (2015).
Efficient zero-knowledge proofs for commitments from learning with errors over
rings. Presented at the ESORICS: European Symposium on Research in Computer Security,
Vienna, Austria: Springer. https://doi.org/10.1007/978-3-319-24174-6_16'
chicago: Benhamouda, Fabrice, Stephan Krenn, Vadim Lyubashevsky, and Krzysztof Z
Pietrzak. “Efficient Zero-Knowledge Proofs for Commitments from Learning with
Errors over Rings.” Lecture Notes in Computer Science. Springer, 2015. https://doi.org/10.1007/978-3-319-24174-6_16.
ieee: F. Benhamouda, S. Krenn, V. Lyubashevsky, and K. Z. Pietrzak, “Efficient zero-knowledge
proofs for commitments from learning with errors over rings,” vol. 9326. Springer,
pp. 305–325, 2015.
ista: Benhamouda F, Krenn S, Lyubashevsky V, Pietrzak KZ. 2015. Efficient zero-knowledge
proofs for commitments from learning with errors over rings. 9326, 305–325.
mla: Benhamouda, Fabrice, et al. Efficient Zero-Knowledge Proofs for Commitments
from Learning with Errors over Rings. Vol. 9326, Springer, 2015, pp. 305–25,
doi:10.1007/978-3-319-24174-6_16.
short: F. Benhamouda, S. Krenn, V. Lyubashevsky, K.Z. Pietrzak, 9326 (2015) 305–325.
conference:
end_date: 2015-09-25
location: Vienna, Austria
name: 'ESORICS: European Symposium on Research in Computer Security'
start_date: 2015-09-21
date_created: 2018-12-11T11:53:15Z
date_published: 2015-01-01T00:00:00Z
date_updated: 2021-01-12T06:52:14Z
day: '01'
ddc:
- '000'
- '004'
department:
- _id: KrPi
doi: 10.1007/978-3-319-24174-6_16
ec_funded: 1
file:
- access_level: open_access
checksum: 6eac4a485b2aa644b2d3f753ed0b280b
content_type: application/pdf
creator: system
date_created: 2018-12-12T10:11:28Z
date_updated: 2020-07-14T12:45:08Z
file_id: '4883'
file_name: IST-2016-678-v1+1_889.pdf
file_size: 494239
relation: main_file
file_date_updated: 2020-07-14T12:45:08Z
has_accepted_license: '1'
intvolume: ' 9326'
language:
- iso: eng
month: '01'
oa: 1
oa_version: Published Version
page: 305 - 325
project:
- _id: 258C570E-B435-11E9-9278-68D0E5697425
call_identifier: FP7
grant_number: '259668'
name: Provable Security for Physical Cryptography
publication_status: published
publisher: Springer
publist_id: '5501'
pubrep_id: '678'
quality_controlled: '1'
scopus_import: 1
series_title: Lecture Notes in Computer Science
status: public
title: Efficient zero-knowledge proofs for commitments from learning with errors over
rings
tmp:
image: /images/cc_by_nc.png
legal_code_url: https://creativecommons.org/licenses/by-nc/4.0/legalcode
name: Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0)
short: CC BY-NC (4.0)
type: conference
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 9326
year: '2015'
...
---
_id: '1650'
abstract:
- lang: eng
text: "We consider the task of deriving a key with high HILL entropy (i.e., being
computationally indistinguishable from a key with high min-entropy) from an unpredictable
source.\r\n\r\nPrevious to this work, the only known way to transform unpredictability
into a key that was ϵ indistinguishable from having min-entropy was via pseudorandomness,
for example by Goldreich-Levin (GL) hardcore bits. This approach has the inherent
limitation that from a source with k bits of unpredictability entropy one can
derive a key of length (and thus HILL entropy) at most k−2log(1/ϵ) bits. In many
settings, e.g. when dealing with biometric data, such a 2log(1/ϵ) bit entropy
loss in not an option. Our main technical contribution is a theorem that states
that in the high entropy regime, unpredictability implies HILL entropy. Concretely,
any variable K with |K|−d bits of unpredictability entropy has the same amount
of so called metric entropy (against real-valued, deterministic distinguishers),
which is known to imply the same amount of HILL entropy. The loss in circuit size
in this argument is exponential in the entropy gap d, and thus this result only
applies for small d (i.e., where the size of distinguishers considered is exponential
in d).\r\n\r\nTo overcome the above restriction, we investigate if it’s possible
to first “condense” unpredictability entropy and make the entropy gap small. We
show that any source with k bits of unpredictability can be condensed into a source
of length k with k−3 bits of unpredictability entropy. Our condenser simply “abuses"
the GL construction and derives a k bit key from a source with k bits of unpredicatibily.
The original GL theorem implies nothing when extracting that many bits, but we
show that in this regime, GL still behaves like a “condenser" for unpredictability.
This result comes with two caveats (1) the loss in circuit size is exponential
in k and (2) we require that the source we start with has no HILL entropy (equivalently,
one can efficiently check if a guess is correct). We leave it as an intriguing
open problem to overcome these restrictions or to prove they’re inherent."
alternative_title:
- LNCS
author:
- first_name: Maciej
full_name: Skórski, Maciej
last_name: Skórski
- first_name: Alexander
full_name: Golovnev, Alexander
last_name: Golovnev
- 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: 'Skórski M, Golovnev A, Pietrzak KZ. Condensed unpredictability . In: Vol 9134.
Springer; 2015:1046-1057. doi:10.1007/978-3-662-47672-7_85'
apa: 'Skórski, M., Golovnev, A., & Pietrzak, K. Z. (2015). Condensed unpredictability (Vol.
9134, pp. 1046–1057). Presented at the ICALP: Automata, Languages and Programming,
Kyoto, Japan: Springer. https://doi.org/10.1007/978-3-662-47672-7_85'
chicago: Skórski, Maciej, Alexander Golovnev, and Krzysztof Z Pietrzak. “Condensed
Unpredictability ,” 9134:1046–57. Springer, 2015. https://doi.org/10.1007/978-3-662-47672-7_85.
ieee: 'M. Skórski, A. Golovnev, and K. Z. Pietrzak, “Condensed unpredictability
,” presented at the ICALP: Automata, Languages and Programming, Kyoto, Japan,
2015, vol. 9134, pp. 1046–1057.'
ista: 'Skórski M, Golovnev A, Pietrzak KZ. 2015. Condensed unpredictability . ICALP:
Automata, Languages and Programming, LNCS, vol. 9134, 1046–1057.'
mla: Skórski, Maciej, et al. Condensed Unpredictability . Vol. 9134, Springer,
2015, pp. 1046–57, doi:10.1007/978-3-662-47672-7_85.
short: M. Skórski, A. Golovnev, K.Z. Pietrzak, in:, Springer, 2015, pp. 1046–1057.
conference:
end_date: 2015-07-10
location: Kyoto, Japan
name: 'ICALP: Automata, Languages and Programming'
start_date: 2015-07-06
date_created: 2018-12-11T11:53:15Z
date_published: 2015-06-20T00:00:00Z
date_updated: 2021-01-12T06:52:15Z
day: '20'
ddc:
- '000'
- '005'
department:
- _id: KrPi
doi: 10.1007/978-3-662-47672-7_85
ec_funded: 1
file:
- access_level: open_access
checksum: e808c7eecb631336fc9f9bf2e8d4ecae
content_type: application/pdf
creator: system
date_created: 2018-12-12T10:08:32Z
date_updated: 2020-07-14T12:45:08Z
file_id: '4693'
file_name: IST-2016-675-v1+1_384.pdf
file_size: 525503
relation: main_file
file_date_updated: 2020-07-14T12:45:08Z
has_accepted_license: '1'
intvolume: ' 9134'
language:
- iso: eng
month: '06'
oa: 1
oa_version: Published Version
page: 1046 - 1057
project:
- _id: 258C570E-B435-11E9-9278-68D0E5697425
call_identifier: FP7
grant_number: '259668'
name: Provable Security for Physical Cryptography
publication_status: published
publisher: Springer
publist_id: '5500'
pubrep_id: '675'
quality_controlled: '1'
scopus_import: 1
status: public
title: 'Condensed unpredictability '
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: 9134
year: '2015'
...
---
_id: '1651'
abstract:
- lang: eng
text: Cryptographic e-cash allows off-line electronic transactions between a bank,
users and merchants in a secure and anonymous fashion. A plethora of e-cash constructions
has been proposed in the literature; however, these traditional e-cash schemes
only allow coins to be transferred once between users and merchants. Ideally,
we would like users to be able to transfer coins between each other multiple times
before deposit, as happens with physical cash. “Transferable” e-cash schemes are
the solution to this problem. Unfortunately, the currently proposed schemes are
either completely impractical or do not achieve the desirable anonymity properties
without compromises, such as assuming the existence of a trusted “judge” who can
trace all coins and users in the system. This paper presents the first efficient
and fully anonymous transferable e-cash scheme without any trusted third parties.
We start by revising the security and anonymity properties of transferable e-cash
to capture issues that were previously overlooked. For our construction we use
the recently proposed malleable signatures by Chase et al. to allow the secure
and anonymous transfer of coins, combined with a new efficient double-spending
detection mechanism. Finally, we discuss an instantiation of our construction.
acknowledgement: Work done as an intern in Microsoft Research Redmond and as a student
at Brown University, where supported by NSF grant 0964379. Supported by the European
Research Council, ERC Starting Grant (259668-PSPC).
alternative_title:
- LNCS
article_processing_charge: No
author:
- first_name: Foteini
full_name: Baldimtsi, Foteini
last_name: Baldimtsi
- first_name: Melissa
full_name: Chase, Melissa
last_name: Chase
- first_name: Georg
full_name: Fuchsbauer, Georg
id: 46B4C3EE-F248-11E8-B48F-1D18A9856A87
last_name: Fuchsbauer
- first_name: Markulf
full_name: Kohlweiss, Markulf
last_name: Kohlweiss
citation:
ama: 'Baldimtsi F, Chase M, Fuchsbauer G, Kohlweiss M. Anonymous transferable e-cash.
In: Public-Key Cryptography - PKC 2015. Vol 9020. Springer; 2015:101-124.
doi:10.1007/978-3-662-46447-2_5'
apa: 'Baldimtsi, F., Chase, M., Fuchsbauer, G., & Kohlweiss, M. (2015). Anonymous
transferable e-cash. In Public-Key Cryptography - PKC 2015 (Vol. 9020,
pp. 101–124). Gaithersburg, MD, United States: Springer. https://doi.org/10.1007/978-3-662-46447-2_5'
chicago: Baldimtsi, Foteini, Melissa Chase, Georg Fuchsbauer, and Markulf Kohlweiss.
“Anonymous Transferable E-Cash.” In Public-Key Cryptography - PKC 2015,
9020:101–24. Springer, 2015. https://doi.org/10.1007/978-3-662-46447-2_5.
ieee: F. Baldimtsi, M. Chase, G. Fuchsbauer, and M. Kohlweiss, “Anonymous transferable
e-cash,” in Public-Key Cryptography - PKC 2015, Gaithersburg, MD, United
States, 2015, vol. 9020, pp. 101–124.
ista: 'Baldimtsi F, Chase M, Fuchsbauer G, Kohlweiss M. 2015. Anonymous transferable
e-cash. Public-Key Cryptography - PKC 2015. PKC: Public Key Crypography, LNCS,
vol. 9020, 101–124.'
mla: Baldimtsi, Foteini, et al. “Anonymous Transferable E-Cash.” Public-Key Cryptography
- PKC 2015, vol. 9020, Springer, 2015, pp. 101–24, doi:10.1007/978-3-662-46447-2_5.
short: F. Baldimtsi, M. Chase, G. Fuchsbauer, M. Kohlweiss, in:, Public-Key Cryptography
- PKC 2015, Springer, 2015, pp. 101–124.
conference:
end_date: 2015-04-01
location: Gaithersburg, MD, United States
name: 'PKC: Public Key Crypography'
start_date: 2015-03-30
date_created: 2018-12-11T11:53:15Z
date_published: 2015-03-17T00:00:00Z
date_updated: 2022-05-23T10:08:37Z
day: '17'
department:
- _id: KrPi
doi: 10.1007/978-3-662-46447-2_5
ec_funded: 1
intvolume: ' 9020'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://doi.org/10.1007/978-3-662-46447-2_5
month: '03'
oa: 1
oa_version: Published Version
page: 101 - 124
project:
- _id: 258C570E-B435-11E9-9278-68D0E5697425
call_identifier: FP7
grant_number: '259668'
name: Provable Security for Physical Cryptography
publication: Public-Key Cryptography - PKC 2015
publication_identifier:
isbn:
- 978-3-662-46446-5
publication_status: published
publisher: Springer
publist_id: '5499'
quality_controlled: '1'
scopus_import: '1'
status: public
title: Anonymous transferable e-cash
type: conference
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 9020
year: '2015'
...
---
_id: '1652'
abstract:
- lang: eng
text: We develop new theoretical tools for proving lower-bounds on the (amortized)
complexity of certain functions in models of parallel computation. We apply the
tools to construct a class of functions with high amortized memory complexity
in the parallel Random Oracle Model (pROM); a variant of the standard ROM allowing
for batches of simultaneous queries. In particular we obtain a new, more robust,
type of Memory-Hard Functions (MHF); a security primitive which has recently been
gaining acceptance in practice as an effective means of countering brute-force
attacks on security relevant functions. Along the way we also demonstrate an important
shortcoming of previous definitions of MHFs and give a new definition addressing
the problem. The tools we develop represent an adaptation of the powerful pebbling
paradigm (initially introduced by Hewitt and Paterson [HP70] and Cook [Coo73])
to a simple and intuitive parallel setting. We define a simple pebbling game Gp
over graphs which aims to abstract parallel computation in an intuitive way. As
a conceptual contribution we define a measure of pebbling complexity for graphs
called cumulative complexity (CC) and show how it overcomes a crucial shortcoming
(in the parallel setting) exhibited by more traditional complexity measures used
in the past. As a main technical contribution we give an explicit construction
of a constant in-degree family of graphs whose CC in Gp approaches maximality
to within a polylogarithmic factor for any graph of equal size (analogous to the
graphs of Tarjan et. al. [PTC76, LT82] for sequential pebbling games). Finally,
for a given graph G and related function fG, we derive a lower-bound on the amortized
memory complexity of fG in the pROM in terms of the CC of G in the game Gp.
author:
- first_name: Joel F
full_name: Alwen, Joel F
id: 2A8DFA8C-F248-11E8-B48F-1D18A9856A87
last_name: Alwen
- first_name: Vladimir
full_name: Serbinenko, Vladimir
last_name: Serbinenko
citation:
ama: 'Alwen JF, Serbinenko V. High parallel complexity graphs and memory-hard functions.
In: Proceedings of the 47th Annual ACM Symposium on Theory of Computing.
ACM; 2015:595-603. doi:10.1145/2746539.2746622'
apa: 'Alwen, J. F., & Serbinenko, V. (2015). High parallel complexity graphs
and memory-hard functions. In Proceedings of the 47th annual ACM symposium
on Theory of computing (pp. 595–603). Portland, OR, United States: ACM. https://doi.org/10.1145/2746539.2746622'
chicago: Alwen, Joel F, and Vladimir Serbinenko. “High Parallel Complexity Graphs
and Memory-Hard Functions.” In Proceedings of the 47th Annual ACM Symposium
on Theory of Computing, 595–603. ACM, 2015. https://doi.org/10.1145/2746539.2746622.
ieee: J. F. Alwen and V. Serbinenko, “High parallel complexity graphs and memory-hard
functions,” in Proceedings of the 47th annual ACM symposium on Theory of computing,
Portland, OR, United States, 2015, pp. 595–603.
ista: 'Alwen JF, Serbinenko V. 2015. High parallel complexity graphs and memory-hard
functions. Proceedings of the 47th annual ACM symposium on Theory of computing.
STOC: Symposium on the Theory of Computing, 595–603.'
mla: Alwen, Joel F., and Vladimir Serbinenko. “High Parallel Complexity Graphs and
Memory-Hard Functions.” Proceedings of the 47th Annual ACM Symposium on Theory
of Computing, ACM, 2015, pp. 595–603, doi:10.1145/2746539.2746622.
short: J.F. Alwen, V. Serbinenko, in:, Proceedings of the 47th Annual ACM Symposium
on Theory of Computing, ACM, 2015, pp. 595–603.
conference:
end_date: 2015-06-17
location: Portland, OR, United States
name: 'STOC: Symposium on the Theory of Computing'
start_date: 2015-06-14
date_created: 2018-12-11T11:53:16Z
date_published: 2015-06-01T00:00:00Z
date_updated: 2021-01-12T06:52:16Z
day: '01'
department:
- _id: KrPi
doi: 10.1145/2746539.2746622
ec_funded: 1
language:
- iso: eng
main_file_link:
- open_access: '1'
url: http://eprint.iacr.org/2014/238
month: '06'
oa: 1
oa_version: Submitted Version
page: 595 - 603
project:
- _id: 258C570E-B435-11E9-9278-68D0E5697425
call_identifier: FP7
grant_number: '259668'
name: Provable Security for Physical Cryptography
publication: Proceedings of the 47th annual ACM symposium on Theory of computing
publication_status: published
publisher: ACM
publist_id: '5498'
quality_controlled: '1'
scopus_import: 1
status: public
title: High parallel complexity graphs and memory-hard functions
type: conference
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
year: '2015'
...
---
_id: '1654'
abstract:
- lang: eng
text: "HMAC and its variant NMAC are the most popular approaches to deriving a MAC
(and more generally, a PRF) from a cryptographic hash function. Despite nearly
two decades of research, their exact security still remains far from understood
in many different contexts. Indeed, recent works have re-surfaced interest for
{\\em generic} attacks, i.e., attacks that treat the compression function of the
underlying hash function as a black box.\r\n\r\nGeneric security can be proved
in a model where the underlying compression function is modeled as a random function
-- yet, to date, the question of proving tight, non-trivial bounds on the generic
security of HMAC/NMAC even as a PRF remains a challenging open question.\r\n\r\nIn
this paper, we ask the question of whether a small modification to HMAC and NMAC
can allow us to exactly characterize the security of the resulting constructions,
while only incurring little penalty with respect to efficiency. To this end, we
present simple variants of NMAC and HMAC, for which we prove tight bounds on the
generic PRF security, expressed in terms of numbers of construction and compression
function queries necessary to break the construction. All of our constructions
are obtained via a (near) {\\em black-box} modification of NMAC and HMAC, which
can be interpreted as an initial step of key-dependent message pre-processing.\r\n\r\nWhile
our focus is on PRF security, a further attractive feature of our new constructions
is that they clearly defeat all recent generic attacks against properties such
as state recovery and universal forgery. These exploit properties of the so-called
``functional graph'' which are not directly accessible in our new constructions. "
alternative_title:
- LNCS
author:
- first_name: Peter
full_name: Gazi, Peter
id: 3E0BFE38-F248-11E8-B48F-1D18A9856A87
last_name: Gazi
- 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: Stefano
full_name: Tessaro, Stefano
last_name: Tessaro
citation:
ama: Gazi P, Pietrzak KZ, Tessaro S. Generic security of NMAC and HMAC with input
whitening. 2015;9453:85-109. doi:10.1007/978-3-662-48800-3_4
apa: 'Gazi, P., Pietrzak, K. Z., & Tessaro, S. (2015). Generic security of NMAC
and HMAC with input whitening. Presented at the ASIACRYPT: Theory and Application
of Cryptology and Information Security, Auckland, New Zealand: Springer. https://doi.org/10.1007/978-3-662-48800-3_4'
chicago: Gazi, Peter, Krzysztof Z Pietrzak, and Stefano Tessaro. “Generic Security
of NMAC and HMAC with Input Whitening.” Lecture Notes in Computer Science. Springer,
2015. https://doi.org/10.1007/978-3-662-48800-3_4.
ieee: P. Gazi, K. Z. Pietrzak, and S. Tessaro, “Generic security of NMAC and HMAC
with input whitening,” vol. 9453. Springer, pp. 85–109, 2015.
ista: Gazi P, Pietrzak KZ, Tessaro S. 2015. Generic security of NMAC and HMAC with
input whitening. 9453, 85–109.
mla: Gazi, Peter, et al. Generic Security of NMAC and HMAC with Input Whitening.
Vol. 9453, Springer, 2015, pp. 85–109, doi:10.1007/978-3-662-48800-3_4.
short: P. Gazi, K.Z. Pietrzak, S. Tessaro, 9453 (2015) 85–109.
conference:
end_date: 2015-12-03
location: Auckland, New Zealand
name: 'ASIACRYPT: Theory and Application of Cryptology and Information Security'
start_date: 2015-11-29
date_created: 2018-12-11T11:53:17Z
date_published: 2015-12-30T00:00:00Z
date_updated: 2021-01-12T06:52:16Z
day: '30'
ddc:
- '004'
- '005'
department:
- _id: KrPi
doi: 10.1007/978-3-662-48800-3_4
ec_funded: 1
file:
- access_level: open_access
checksum: d1e53203db2d8573a560995ccdffac62
content_type: application/pdf
creator: system
date_created: 2018-12-12T10:09:09Z
date_updated: 2020-07-14T12:45:08Z
file_id: '4732'
file_name: IST-2016-676-v1+1_881.pdf
file_size: 512071
relation: main_file
file_date_updated: 2020-07-14T12:45:08Z
has_accepted_license: '1'
intvolume: ' 9453'
language:
- iso: eng
month: '12'
oa: 1
oa_version: Submitted Version
page: 85 - 109
project:
- _id: 258C570E-B435-11E9-9278-68D0E5697425
call_identifier: FP7
grant_number: '259668'
name: Provable Security for Physical Cryptography
publication_status: published
publisher: Springer
publist_id: '5496'
pubrep_id: '676'
quality_controlled: '1'
scopus_import: 1
series_title: Lecture Notes in Computer Science
status: public
title: Generic security of NMAC and HMAC with input whitening
type: conference
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 9453
year: '2015'
...
---
_id: '1668'
abstract:
- lang: eng
text: "We revisit the security (as a pseudorandom permutation) of cascading-based
constructions for block-cipher key-length extension. Previous works typically
considered the extreme case where the adversary is given the entire codebook of
the construction, the only complexity measure being the number qe of queries to
the underlying ideal block cipher, representing adversary’s secret-key-independent
computation. Here, we initiate a systematic study of the more natural case of
an adversary restricted to adaptively learning a number qc of plaintext/ciphertext
pairs that is less than the entire codebook. For any such qc, we aim to determine
the highest number of block-cipher queries qe the adversary can issue without
being able to successfully distinguish the construction (under a secret key) from
a random permutation.\r\nMore concretely, we show the following results for key-length
extension schemes using a block cipher with n-bit blocks and κ-bit keys:\r\nPlain
cascades of length ℓ=2r+1 are secure whenever qcqre≪2r(κ+n), qc≪2κ and qe≪22κ.
The bound for r=1 also applies to two-key triple encryption (as used within Triple
DES).\r\nThe r-round XOR-cascade is secure as long as qcqre≪2r(κ+n), matching
an attack by Gaži (CRYPTO 2013).\r\nWe fully characterize the security of Gaži
and Tessaro’s two-call "
alternative_title:
- LNCS
author:
- first_name: Peter
full_name: Gazi, Peter
id: 3E0BFE38-F248-11E8-B48F-1D18A9856A87
last_name: Gazi
- first_name: Jooyoung
full_name: Lee, Jooyoung
last_name: Lee
- first_name: Yannick
full_name: Seurin, Yannick
last_name: Seurin
- first_name: John
full_name: Steinberger, John
last_name: Steinberger
- first_name: Stefano
full_name: Tessaro, Stefano
last_name: Tessaro
citation:
ama: 'Gazi P, Lee J, Seurin Y, Steinberger J, Tessaro S. Relaxing full-codebook
security: A refined analysis of key-length extension schemes. 2015;9054:319-341.
doi:10.1007/978-3-662-48116-5_16'
apa: 'Gazi, P., Lee, J., Seurin, Y., Steinberger, J., & Tessaro, S. (2015).
Relaxing full-codebook security: A refined analysis of key-length extension schemes.
Presented at the FSE: Fast Software Encryption, Istanbul, Turkey: Springer. https://doi.org/10.1007/978-3-662-48116-5_16'
chicago: 'Gazi, Peter, Jooyoung Lee, Yannick Seurin, John Steinberger, and Stefano
Tessaro. “Relaxing Full-Codebook Security: A Refined Analysis of Key-Length Extension
Schemes.” Lecture Notes in Computer Science. Springer, 2015. https://doi.org/10.1007/978-3-662-48116-5_16.'
ieee: 'P. Gazi, J. Lee, Y. Seurin, J. Steinberger, and S. Tessaro, “Relaxing full-codebook
security: A refined analysis of key-length extension schemes,” vol. 9054. Springer,
pp. 319–341, 2015.'
ista: 'Gazi P, Lee J, Seurin Y, Steinberger J, Tessaro S. 2015. Relaxing full-codebook
security: A refined analysis of key-length extension schemes. 9054, 319–341.'
mla: 'Gazi, Peter, et al. Relaxing Full-Codebook Security: A Refined Analysis
of Key-Length Extension Schemes. Vol. 9054, Springer, 2015, pp. 319–41, doi:10.1007/978-3-662-48116-5_16.'
short: P. Gazi, J. Lee, Y. Seurin, J. Steinberger, S. Tessaro, 9054 (2015) 319–341.
conference:
end_date: 2015-03-11
location: Istanbul, Turkey
name: 'FSE: Fast Software Encryption'
start_date: 2015-03-08
date_created: 2018-12-11T11:53:22Z
date_published: 2015-08-12T00:00:00Z
date_updated: 2020-08-11T10:09:26Z
day: '12'
department:
- _id: KrPi
doi: 10.1007/978-3-662-48116-5_16
ec_funded: 1
intvolume: ' 9054'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: http://eprint.iacr.org/2015/397
month: '08'
oa: 1
oa_version: Submitted Version
page: 319 - 341
project:
- _id: 258C570E-B435-11E9-9278-68D0E5697425
call_identifier: FP7
grant_number: '259668'
name: Provable Security for Physical Cryptography
publication_status: published
publisher: Springer
publist_id: '5481'
quality_controlled: '1'
scopus_import: 1
series_title: Lecture Notes in Computer Science
status: public
title: 'Relaxing full-codebook security: A refined analysis of key-length extension
schemes'
type: conference
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 9054
year: '2015'
...
---
_id: '1669'
abstract:
- lang: eng
text: Computational notions of entropy (a.k.a. pseudoentropy) have found many applications,
including leakage-resilient cryptography, deterministic encryption or memory delegation.
The most important tools to argue about pseudoentropy are chain rules, which quantify
by how much (in terms of quantity and quality) the pseudoentropy of a given random
variable X decreases when conditioned on some other variable Z (think for example
of X as a secret key and Z as information leaked by a side-channel). In this paper
we give a very simple and modular proof of the chain rule for HILL pseudoentropy,
improving best known parameters. Our version allows for increasing the acceptable
length of leakage in applications up to a constant factor compared to the best
previous bounds. As a contribution of independent interest, we provide a comprehensive
study of all known versions of the chain rule, comparing their worst-case strength
and limitations.
alternative_title:
- LNCS
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
last_name: Skórski
citation:
ama: Pietrzak KZ, Skórski M. The chain rule for HILL pseudoentropy, revisited. 2015;9230:81-98.
doi:10.1007/978-3-319-22174-8_5
apa: 'Pietrzak, K. Z., & Skórski, M. (2015). The chain rule for HILL pseudoentropy,
revisited. Presented at the LATINCRYPT: Cryptology and Information Security in
Latin America, Guadalajara, Mexico: Springer. https://doi.org/10.1007/978-3-319-22174-8_5'
chicago: Pietrzak, Krzysztof Z, and Maciej Skórski. “The Chain Rule for HILL Pseudoentropy,
Revisited.” Lecture Notes in Computer Science. Springer, 2015. https://doi.org/10.1007/978-3-319-22174-8_5.
ieee: K. Z. Pietrzak and M. Skórski, “The chain rule for HILL pseudoentropy, revisited,”
vol. 9230. Springer, pp. 81–98, 2015.
ista: Pietrzak KZ, Skórski M. 2015. The chain rule for HILL pseudoentropy, revisited.
9230, 81–98.
mla: Pietrzak, Krzysztof Z., and Maciej Skórski. The Chain Rule for HILL Pseudoentropy,
Revisited. Vol. 9230, Springer, 2015, pp. 81–98, doi:10.1007/978-3-319-22174-8_5.
short: K.Z. Pietrzak, M. Skórski, 9230 (2015) 81–98.
conference:
end_date: 2015-08-26
location: Guadalajara, Mexico
name: 'LATINCRYPT: Cryptology and Information Security in Latin America'
start_date: 2015-08-23
date_created: 2018-12-11T11:53:22Z
date_published: 2015-08-15T00:00:00Z
date_updated: 2021-01-12T06:52:24Z
day: '15'
ddc:
- '005'
department:
- _id: KrPi
doi: 10.1007/978-3-319-22174-8_5
ec_funded: 1
file:
- access_level: open_access
checksum: 8cd4215b83efba720e8cf27c23ff4781
content_type: application/pdf
creator: system
date_created: 2018-12-12T10:18:29Z
date_updated: 2020-07-14T12:45:11Z
file_id: '5351'
file_name: IST-2016-669-v1+1_599.pdf
file_size: 443340
relation: main_file
file_date_updated: 2020-07-14T12:45:11Z
has_accepted_license: '1'
intvolume: ' 9230'
language:
- iso: eng
month: '08'
oa: 1
oa_version: Submitted Version
page: 81 - 98
project:
- _id: 258C570E-B435-11E9-9278-68D0E5697425
call_identifier: FP7
grant_number: '259668'
name: Provable Security for Physical Cryptography
publication_status: published
publisher: Springer
publist_id: '5480'
pubrep_id: '669'
quality_controlled: '1'
scopus_import: 1
series_title: Lecture Notes in Computer Science
status: public
title: The chain rule for HILL pseudoentropy, revisited
type: conference
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 9230
year: '2015'
...
---
_id: '1671'
abstract:
- lang: eng
text: This paper studies the concrete security of PRFs and MACs obtained by keying
hash functions based on the sponge paradigm. One such hash function is KECCAK,
selected as NIST’s new SHA-3 standard. In contrast to other approaches like HMAC,
the exact security of keyed sponges is not well understood. Indeed, recent security
analyses delivered concrete security bounds which are far from existing attacks.
This paper aims to close this gap. We prove (nearly) exact bounds on the concrete
PRF security of keyed sponges using a random permutation. These bounds are tight
for the most relevant ranges of parameters, i.e., for messages of length (roughly)
l ≤ min{2n/4, 2r} blocks, where n is the state size and r is the desired output
length; and for l ≤ q queries (to the construction or the underlying permutation).
Moreover, we also improve standard-model bounds. As an intermediate step of independent
interest, we prove tight bounds on the PRF security of the truncated CBC-MAC construction,
which operates as plain CBC-MAC, but only returns a prefix of the output.
alternative_title:
- LNCS
author:
- first_name: Peter
full_name: Gazi, Peter
id: 3E0BFE38-F248-11E8-B48F-1D18A9856A87
last_name: Gazi
- 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: Stefano
full_name: Tessaro, Stefano
last_name: Tessaro
citation:
ama: 'Gazi P, Pietrzak KZ, Tessaro S. The exact PRF security of truncation: Tight
bounds for keyed sponges and truncated CBC. In: Vol 9215. Springer; 2015:368-387.
doi:10.1007/978-3-662-47989-6_18'
apa: 'Gazi, P., Pietrzak, K. Z., & Tessaro, S. (2015). The exact PRF security
of truncation: Tight bounds for keyed sponges and truncated CBC (Vol. 9215, pp.
368–387). Presented at the CRYPTO: International Cryptology Conference, Santa
Barbara, CA, United States: Springer. https://doi.org/10.1007/978-3-662-47989-6_18'
chicago: 'Gazi, Peter, Krzysztof Z Pietrzak, and Stefano Tessaro. “The Exact PRF
Security of Truncation: Tight Bounds for Keyed Sponges and Truncated CBC,” 9215:368–87.
Springer, 2015. https://doi.org/10.1007/978-3-662-47989-6_18.'
ieee: 'P. Gazi, K. Z. Pietrzak, and S. Tessaro, “The exact PRF security of truncation:
Tight bounds for keyed sponges and truncated CBC,” presented at the CRYPTO: International
Cryptology Conference, Santa Barbara, CA, United States, 2015, vol. 9215, pp.
368–387.'
ista: 'Gazi P, Pietrzak KZ, Tessaro S. 2015. The exact PRF security of truncation:
Tight bounds for keyed sponges and truncated CBC. CRYPTO: International Cryptology
Conference, LNCS, vol. 9215, 368–387.'
mla: 'Gazi, Peter, et al. The Exact PRF Security of Truncation: Tight Bounds
for Keyed Sponges and Truncated CBC. Vol. 9215, Springer, 2015, pp. 368–87,
doi:10.1007/978-3-662-47989-6_18.'
short: P. Gazi, K.Z. Pietrzak, S. Tessaro, in:, Springer, 2015, pp. 368–387.
conference:
end_date: 2015-08-20
location: Santa Barbara, CA, United States
name: 'CRYPTO: International Cryptology Conference'
start_date: 2015-08-16
date_created: 2018-12-11T11:53:23Z
date_published: 2015-08-01T00:00:00Z
date_updated: 2021-01-12T06:52:25Z
day: '01'
ddc:
- '004'
- '005'
department:
- _id: KrPi
doi: 10.1007/978-3-662-47989-6_18
ec_funded: 1
file:
- access_level: open_access
checksum: 17d854227b3b753fd34f5d29e5b5a32e
content_type: application/pdf
creator: system
date_created: 2018-12-12T10:10:38Z
date_updated: 2020-07-14T12:45:11Z
file_id: '4827'
file_name: IST-2016-673-v1+1_053.pdf
file_size: 592296
relation: main_file
file_date_updated: 2020-07-14T12:45:11Z
has_accepted_license: '1'
intvolume: ' 9215'
language:
- iso: eng
month: '08'
oa: 1
oa_version: Submitted Version
page: 368 - 387
project:
- _id: 258C570E-B435-11E9-9278-68D0E5697425
call_identifier: FP7
grant_number: '259668'
name: Provable Security for Physical Cryptography
publication_status: published
publisher: Springer
publist_id: '5478'
pubrep_id: '673'
quality_controlled: '1'
scopus_import: 1
status: public
title: 'The exact PRF security of truncation: Tight bounds for keyed sponges and truncated
CBC'
type: conference
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 9215
year: '2015'
...
---
_id: '1672'
abstract:
- lang: eng
text: Composable notions of incoercibility aim to forbid a coercer from using anything
beyond the coerced parties’ inputs and outputs to catch them when they try to
deceive him. Existing definitions are restricted to weak coercion types, and/or
are not universally composable. Furthermore, they often make too strong assumptions
on the knowledge of coerced parties—e.g., they assume they known the identities
and/or the strategies of other coerced parties, or those of corrupted parties—
which makes them unsuitable for applications of incoercibility such as e-voting,
where colluding adversarial parties may attempt to coerce honest voters, e.g.,
by offering them money for a promised vote, and use their own view to check that
the voter keeps his end of the bargain. In this work we put forward the first
universally composable notion of incoercible multi-party computation, which satisfies
the above intuition and does not assume collusions among coerced parties or knowledge
of the corrupted set. We define natural notions of UC incoercibility corresponding
to standard coercion-types, i.e., receipt-freeness and resistance to full-active
coercion. Importantly, our suggested notion has the unique property that it builds
on top of the well studied UC framework by Canetti instead of modifying it. This
guarantees backwards compatibility, and allows us to inherit results from the
rich UC literature. We then present MPC protocols which realize our notions of
UC incoercibility given access to an arguably minimal setup—namely honestly generate
tamper-proof hardware performing a very simple cryptographic operation—e.g., a
smart card. This is, to our knowledge, the first proposed construction of an MPC
protocol (for more than two parties) that is incoercibly secure and universally
composable, and therefore the first construction of a universally composable receipt-free
e-voting protocol.
acknowledgement: Joël Alwen was supported by the ERC starting grant (259668-PSPC).
Rafail Ostrovsky was supported in part by NSF grants 09165174, 1065276, 1118126
and 1136174, US-Israel BSF grant 2008411, OKAWA Foundation Research Award, IBM Faculty
Research Award, Xerox Faculty Research Award, B. John Garrick Foundation Award,
Teradata Research Award, Lockheed-Martin Corporation Research Award, and the Defense
Advanced Research Projects Agency through the U.S. Office of Naval Research under
Contract N00014 -11 -1-0392. The views expressed are those of the author and do
not reflect the official policy or position of the Department of Defense or the
U.S. Government. Vassilis Zikas was supported in part by the Swiss National Science
Foundation (SNF) via the Ambizione grant PZ00P-2142549.
alternative_title:
- LNCS
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: Rafail
full_name: Ostrovsky, Rafail
last_name: Ostrovsky
- first_name: Hongsheng
full_name: Zhou, Hongsheng
last_name: Zhou
- first_name: Vassilis
full_name: Zikas, Vassilis
last_name: Zikas
citation:
ama: 'Alwen JF, Ostrovsky R, Zhou H, Zikas V. Incoercible multi-party computation
and universally composable receipt-free voting. In: Advances in Cryptology
- CRYPTO 2015. Vol 9216. Lecture Notes in Computer Science. Springer; 2015:763-780.
doi:10.1007/978-3-662-48000-7_37'
apa: 'Alwen, J. F., Ostrovsky, R., Zhou, H., & Zikas, V. (2015). Incoercible
multi-party computation and universally composable receipt-free voting. In Advances
in Cryptology - CRYPTO 2015 (Vol. 9216, pp. 763–780). Santa Barbara, CA, United
States: Springer. https://doi.org/10.1007/978-3-662-48000-7_37'
chicago: Alwen, Joel F, Rafail Ostrovsky, Hongsheng Zhou, and Vassilis Zikas. “Incoercible
Multi-Party Computation and Universally Composable Receipt-Free Voting.” In Advances
in Cryptology - CRYPTO 2015, 9216:763–80. Lecture Notes in Computer Science.
Springer, 2015. https://doi.org/10.1007/978-3-662-48000-7_37.
ieee: J. F. Alwen, R. Ostrovsky, H. Zhou, and V. Zikas, “Incoercible multi-party
computation and universally composable receipt-free voting,” in Advances in
Cryptology - CRYPTO 2015, Santa Barbara, CA, United States, 2015, vol. 9216,
pp. 763–780.
ista: 'Alwen JF, Ostrovsky R, Zhou H, Zikas V. 2015. Incoercible multi-party computation
and universally composable receipt-free voting. Advances in Cryptology - CRYPTO
2015. CRYPTO: International Cryptology ConferenceLecture Notes in Computer Science,
LNCS, vol. 9216, 763–780.'
mla: Alwen, Joel F., et al. “Incoercible Multi-Party Computation and Universally
Composable Receipt-Free Voting.” Advances in Cryptology - CRYPTO 2015,
vol. 9216, Springer, 2015, pp. 763–80, doi:10.1007/978-3-662-48000-7_37.
short: J.F. Alwen, R. Ostrovsky, H. Zhou, V. Zikas, in:, Advances in Cryptology
- CRYPTO 2015, Springer, 2015, pp. 763–780.
conference:
end_date: 2015-08-20
location: Santa Barbara, CA, United States
name: 'CRYPTO: International Cryptology Conference'
start_date: 2015-08-16
date_created: 2018-12-11T11:53:23Z
date_published: 2015-08-01T00:00:00Z
date_updated: 2022-06-07T09:51:55Z
day: '01'
ddc:
- '000'
department:
- _id: KrPi
doi: 10.1007/978-3-662-48000-7_37
ec_funded: 1
file:
- access_level: open_access
checksum: 5b6649e80d1f781a8910f7cce6427f78
content_type: application/pdf
creator: dernst
date_created: 2020-05-15T08:55:29Z
date_updated: 2020-07-14T12:45:11Z
file_id: '7853'
file_name: 2015_CRYPTO_Alwen.pdf
file_size: 397363
relation: main_file
file_date_updated: 2020-07-14T12:45:11Z
has_accepted_license: '1'
intvolume: ' 9216'
language:
- iso: eng
month: '08'
oa: 1
oa_version: Submitted Version
page: 763 - 780
project:
- _id: 258C570E-B435-11E9-9278-68D0E5697425
call_identifier: FP7
grant_number: '259668'
name: Provable Security for Physical Cryptography
publication: Advances in Cryptology - CRYPTO 2015
publication_identifier:
eisbn:
- 978-3-662-48000-7
isbn:
- 978-3-662-47999-5
publication_status: published
publisher: Springer
publist_id: '5476'
quality_controlled: '1'
scopus_import: '1'
series_title: Lecture Notes in Computer Science
status: public
title: Incoercible multi-party computation and universally composable receipt-free
voting
type: conference
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 9216
year: '2015'
...
---
_id: '1675'
abstract:
- lang: eng
text: Proofs of work (PoW) have been suggested by Dwork and Naor (Crypto’92) as
protection to a shared resource. The basic idea is to ask the service requestor
to dedicate some non-trivial amount of computational work to every request. The
original applications included prevention of spam and protection against denial
of service attacks. More recently, PoWs have been used to prevent double spending
in the Bitcoin digital currency system. In this work, we put forward an alternative
concept for PoWs - so-called proofs of space (PoS), where a service requestor
must dedicate a significant amount of disk space as opposed to computation. We
construct secure PoS schemes in the random oracle model (with one additional mild
assumption required for the proof to go through), using graphs with high “pebbling
complexity” and Merkle hash-trees. We discuss some applications, including follow-up
work where a decentralized digital currency scheme called Spacecoin is constructed
that uses PoS (instead of wasteful PoW like in Bitcoin) to prevent double spending.
The main technical contribution of this work is the construction of (directed,
loop-free) graphs on N vertices with in-degree O(log logN) such that even if one
places Θ(N) pebbles on the nodes of the graph, there’s a constant fraction of
nodes that needs Θ(N) steps to be pebbled (where in every step one can put a pebble
on a node if all its parents have a pebble).
alternative_title:
- LNCS
author:
- first_name: Stefan
full_name: Dziembowski, Stefan
last_name: Dziembowski
- first_name: Sebastian
full_name: Faust, Sebastian
last_name: Faust
- first_name: Vladimir
full_name: Kolmogorov, Vladimir
id: 3D50B0BA-F248-11E8-B48F-1D18A9856A87
last_name: Kolmogorov
- 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: Dziembowski S, Faust S, Kolmogorov V, Pietrzak KZ. Proofs of space. 2015;9216:585-605.
doi:10.1007/978-3-662-48000-7_29
apa: 'Dziembowski, S., Faust, S., Kolmogorov, V., & Pietrzak, K. Z. (2015).
Proofs of space. Presented at the CRYPTO: International Cryptology Conference,
Santa Barbara, CA, United States: Springer. https://doi.org/10.1007/978-3-662-48000-7_29'
chicago: Dziembowski, Stefan, Sebastian Faust, Vladimir Kolmogorov, and Krzysztof
Z Pietrzak. “Proofs of Space.” Lecture Notes in Computer Science. Springer, 2015.
https://doi.org/10.1007/978-3-662-48000-7_29.
ieee: S. Dziembowski, S. Faust, V. Kolmogorov, and K. Z. Pietrzak, “Proofs of space,”
vol. 9216. Springer, pp. 585–605, 2015.
ista: Dziembowski S, Faust S, Kolmogorov V, Pietrzak KZ. 2015. Proofs of space.
9216, 585–605.
mla: Dziembowski, Stefan, et al. Proofs of Space. Vol. 9216, Springer, 2015,
pp. 585–605, doi:10.1007/978-3-662-48000-7_29.
short: S. Dziembowski, S. Faust, V. Kolmogorov, K.Z. Pietrzak, 9216 (2015) 585–605.
conference:
end_date: 2015-08-20
location: Santa Barbara, CA, United States
name: 'CRYPTO: International Cryptology Conference'
start_date: 2015-08-16
date_created: 2018-12-11T11:53:24Z
date_published: 2015-08-01T00:00:00Z
date_updated: 2023-02-23T10:35:50Z
day: '01'
department:
- _id: VlKo
- _id: KrPi
doi: 10.1007/978-3-662-48000-7_29
ec_funded: 1
intvolume: ' 9216'
language:
- iso: eng
month: '08'
oa_version: None
page: 585 - 605
project:
- _id: 25FBA906-B435-11E9-9278-68D0E5697425
call_identifier: FP7
grant_number: '616160'
name: 'Discrete Optimization in Computer Vision: Theory and Practice'
- _id: 258C570E-B435-11E9-9278-68D0E5697425
call_identifier: FP7
grant_number: '259668'
name: Provable Security for Physical Cryptography
publication_status: published
publisher: Springer
publist_id: '5474'
pubrep_id: '671'
quality_controlled: '1'
related_material:
record:
- id: '2274'
relation: earlier_version
status: public
scopus_import: 1
series_title: Lecture Notes in Computer Science
status: public
title: Proofs of space
type: conference
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 9216
year: '2015'
...
---
_id: '1474'
abstract:
- lang: eng
text: Cryptographic access control offers selective access to encrypted data via
a combination of key management and functionality-rich cryptographic schemes,
such as attribute-based encryption. Using this approach, publicly available meta-data
may inadvertently leak information on the access policy that is enforced by cryptography,
which renders cryptographic access control unusable in settings where this information
is highly sensitive. We begin to address this problem by presenting rigorous definitions
for policy privacy in cryptographic access control. For concreteness we set our
results in the model of Role-Based Access Control (RBAC), where we identify and
formalize several different flavors of privacy, however, our framework should
serve as inspiration for other models of access control. Based on our insights
we propose a new system which significantly improves on the privacy properties
of state-of-the-art constructions. Our design is based on a novel type of privacy-preserving
attribute-based encryption, which we introduce and show how to instantiate. We
present our results in the context of a cryptographic RBAC system by Ferrara et
al. (CSF'13), which uses cryptography to control read access to files, while write
access is still delegated to trusted monitors. We give an extension of the construction
that permits cryptographic control over write access. Our construction assumes
that key management uses out-of-band channels between the policy enforcer and
the users but eliminates completely the need for monitoring read/write access
to the data.
article_processing_charge: No
author:
- first_name: Anna
full_name: Ferrara, Anna
last_name: Ferrara
- first_name: Georg
full_name: Fuchsbauer, Georg
id: 46B4C3EE-F248-11E8-B48F-1D18A9856A87
last_name: Fuchsbauer
- first_name: Bin
full_name: Liu, Bin
last_name: Liu
- first_name: Bogdan
full_name: Warinschi, Bogdan
last_name: Warinschi
citation:
ama: 'Ferrara A, Fuchsbauer G, Liu B, Warinschi B. Policy privacy in cryptographic
access control. In: IEEE; 2015:46-60. doi:10.1109/CSF.2015.11'
apa: 'Ferrara, A., Fuchsbauer, G., Liu, B., & Warinschi, B. (2015). Policy privacy
in cryptographic access control (pp. 46–60). Presented at the CSF: Computer Security
Foundations, Verona, Italy: IEEE. https://doi.org/10.1109/CSF.2015.11'
chicago: Ferrara, Anna, Georg Fuchsbauer, Bin Liu, and Bogdan Warinschi. “Policy
Privacy in Cryptographic Access Control,” 46–60. IEEE, 2015. https://doi.org/10.1109/CSF.2015.11.
ieee: 'A. Ferrara, G. Fuchsbauer, B. Liu, and B. Warinschi, “Policy privacy in cryptographic
access control,” presented at the CSF: Computer Security Foundations, Verona,
Italy, 2015, pp. 46–60.'
ista: 'Ferrara A, Fuchsbauer G, Liu B, Warinschi B. 2015. Policy privacy in cryptographic
access control. CSF: Computer Security Foundations, 46–60.'
mla: Ferrara, Anna, et al. Policy Privacy in Cryptographic Access Control.
IEEE, 2015, pp. 46–60, doi:10.1109/CSF.2015.11.
short: A. Ferrara, G. Fuchsbauer, B. Liu, B. Warinschi, in:, IEEE, 2015, pp. 46–60.
conference:
end_date: 2015-07-17
location: Verona, Italy
name: 'CSF: Computer Security Foundations'
start_date: 2015-07-13
date_created: 2018-12-11T11:52:14Z
date_published: 2015-09-04T00:00:00Z
date_updated: 2021-01-12T06:50:59Z
day: '04'
department:
- _id: KrPi
doi: 10.1109/CSF.2015.11
ec_funded: 1
language:
- iso: eng
main_file_link:
- open_access: '1'
url: http://epubs.surrey.ac.uk/808055/
month: '09'
oa: 1
oa_version: Submitted Version
page: 46-60
project:
- _id: 258C570E-B435-11E9-9278-68D0E5697425
call_identifier: FP7
grant_number: '259668'
name: Provable Security for Physical Cryptography
publication_status: published
publisher: IEEE
publist_id: '5722'
quality_controlled: '1'
status: public
title: Policy privacy in cryptographic access control
type: conference
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
year: '2015'
...