---
_id: '7896'
abstract:
- lang: eng
text: "A search problem lies in the complexity class FNP if a solution to the given
instance of the problem can be verified efficiently. The complexity class TFNP
consists of all search problems in FNP that are total in the sense that a solution
is guaranteed to exist. TFNP contains a host of interesting problems from fields
such as algorithmic game theory, computational topology, number theory and combinatorics.
Since TFNP is a semantic class, it is unlikely to have a complete problem. Instead,
one studies its syntactic subclasses which are defined based on the combinatorial
principle used to argue totality. Of particular interest is the subclass PPAD,
which contains important problems\r\nlike computing Nash equilibrium for bimatrix
games and computational counterparts of several fixed-point theorems as complete.
In the thesis, we undertake the study of averagecase hardness of TFNP, and in
particular its subclass PPAD.\r\nAlmost nothing was known about average-case hardness
of PPAD before a series of recent results showed how to achieve it using a cryptographic
primitive called program obfuscation.\r\nHowever, it is currently not known how
to construct program obfuscation from standard cryptographic assumptions. Therefore,
it is desirable to relax the assumption under which average-case hardness of PPAD
can be shown. In the thesis we take a step in this direction. First, we show that
assuming the (average-case) hardness of a numbertheoretic\r\nproblem related to
factoring of integers, which we call Iterated-Squaring, PPAD is hard-on-average
in the random-oracle model. Then we strengthen this result to show that the average-case
hardness of PPAD reduces to the (adaptive) soundness of the Fiat-Shamir Transform,
a well-known technique used to compile a public-coin interactive protocol into
a non-interactive one. As a corollary, we obtain average-case hardness for PPAD
in the random-oracle model assuming the worst-case hardness of #SAT. Moreover,
the above results can all be strengthened to obtain average-case hardness for
the class CLS ⊆ PPAD.\r\nOur main technical contribution is constructing incrementally-verifiable
procedures for computing Iterated-Squaring and #SAT. By incrementally-verifiable,
we mean that every intermediate state of the computation includes a proof of its
correctness, and the proof can be updated and verified in polynomial time. Previous
constructions of such procedures relied on strong, non-standard assumptions. Instead,
we introduce a technique called recursive proof-merging to obtain the same from
weaker assumptions. "
alternative_title:
- ISTA Thesis
article_processing_charge: No
author:
- first_name: Chethan
full_name: Kamath Hosdurg, Chethan
id: 4BD3F30E-F248-11E8-B48F-1D18A9856A87
last_name: Kamath Hosdurg
citation:
ama: Kamath Hosdurg C. On the average-case hardness of total search problems. 2020.
doi:10.15479/AT:ISTA:7896
apa: Kamath Hosdurg, C. (2020). On the average-case hardness of total search
problems. Institute of Science and Technology Austria. https://doi.org/10.15479/AT:ISTA:7896
chicago: Kamath Hosdurg, Chethan. “On the Average-Case Hardness of Total Search
Problems.” Institute of Science and Technology Austria, 2020. https://doi.org/10.15479/AT:ISTA:7896.
ieee: C. Kamath Hosdurg, “On the average-case hardness of total search problems,”
Institute of Science and Technology Austria, 2020.
ista: Kamath Hosdurg C. 2020. On the average-case hardness of total search problems.
Institute of Science and Technology Austria.
mla: Kamath Hosdurg, Chethan. On the Average-Case Hardness of Total Search Problems.
Institute of Science and Technology Austria, 2020, doi:10.15479/AT:ISTA:7896.
short: C. Kamath Hosdurg, On the Average-Case Hardness of Total Search Problems,
Institute of Science and Technology Austria, 2020.
date_created: 2020-05-26T14:08:55Z
date_published: 2020-05-25T00:00:00Z
date_updated: 2023-09-07T13:15:55Z
day: '25'
ddc:
- '000'
degree_awarded: PhD
department:
- _id: KrPi
doi: 10.15479/AT:ISTA:7896
ec_funded: 1
file:
- access_level: open_access
checksum: b39e2e1c376f5819b823fb7077491c64
content_type: application/pdf
creator: dernst
date_created: 2020-05-26T14:08:13Z
date_updated: 2020-07-14T12:48:04Z
file_id: '7897'
file_name: 2020_Thesis_Kamath.pdf
file_size: 1622742
relation: main_file
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checksum: 8b26ba729c1a85ac6bea775f5d73cdc7
content_type: application/x-zip-compressed
creator: dernst
date_created: 2020-05-26T14:08:23Z
date_updated: 2020-07-14T12:48:04Z
file_id: '7898'
file_name: Thesis_Kamath.zip
file_size: 15301529
relation: source_file
file_date_updated: 2020-07-14T12:48:04Z
has_accepted_license: '1'
language:
- iso: eng
license: https://creativecommons.org/licenses/by/4.0/
month: '05'
oa: 1
oa_version: Published Version
page: '126'
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
related_material:
record:
- id: '6677'
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: On the average-case hardness of total search problems
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: dissertation
user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1
year: '2020'
...
---
_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: '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
- access_level: closed
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: '1187'
abstract:
- lang: eng
text: We construct efficient authentication protocols and message authentication
codes (MACs) whose security can be reduced to the learning parity with noise (LPN)
problem. Despite a large body of work—starting with the (Formula presented.) protocol
of Hopper and Blum in 2001—until now it was not even known how to construct an
efficient authentication protocol from LPN which is secure against man-in-the-middle
attacks. A MAC implies such a (two-round) protocol.
article_processing_charge: No
article_type: original
author:
- 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
- first_name: Daniele
full_name: Venturi, Daniele
last_name: Venturi
- first_name: David
full_name: Cash, David
last_name: Cash
- first_name: Abhishek
full_name: Jain, Abhishek
last_name: Jain
citation:
ama: Kiltz E, Pietrzak KZ, Venturi D, Cash D, Jain A. Efficient authentication from
hard learning problems. Journal of Cryptology. 2017;30(4):1238-1275. doi:10.1007/s00145-016-9247-3
apa: Kiltz, E., Pietrzak, K. Z., Venturi, D., Cash, D., & Jain, A. (2017). Efficient
authentication from hard learning problems. Journal of Cryptology. Springer.
https://doi.org/10.1007/s00145-016-9247-3
chicago: Kiltz, Eike, Krzysztof Z Pietrzak, Daniele Venturi, David Cash, and Abhishek
Jain. “Efficient Authentication from Hard Learning Problems.” Journal of Cryptology.
Springer, 2017. https://doi.org/10.1007/s00145-016-9247-3.
ieee: E. Kiltz, K. Z. Pietrzak, D. Venturi, D. Cash, and A. Jain, “Efficient authentication
from hard learning problems,” Journal of Cryptology, vol. 30, no. 4. Springer,
pp. 1238–1275, 2017.
ista: Kiltz E, Pietrzak KZ, Venturi D, Cash D, Jain A. 2017. Efficient authentication
from hard learning problems. Journal of Cryptology. 30(4), 1238–1275.
mla: Kiltz, Eike, et al. “Efficient Authentication from Hard Learning Problems.”
Journal of Cryptology, vol. 30, no. 4, Springer, 2017, pp. 1238–75, doi:10.1007/s00145-016-9247-3.
short: E. Kiltz, K.Z. Pietrzak, D. Venturi, D. Cash, A. Jain, Journal of Cryptology
30 (2017) 1238–1275.
date_created: 2018-12-11T11:50:37Z
date_published: 2017-10-01T00:00:00Z
date_updated: 2023-09-20T11:20:58Z
day: '01'
ddc:
- '000'
department:
- _id: KrPi
doi: 10.1007/s00145-016-9247-3
ec_funded: 1
external_id:
isi:
- '000410788600007'
file:
- access_level: open_access
checksum: c647520d115b772a1682fc06fa273eb1
content_type: application/pdf
creator: dernst
date_created: 2020-05-14T16:30:17Z
date_updated: 2020-07-14T12:44:37Z
file_id: '7843'
file_name: 2017_JournalCrypto_Kiltz.pdf
file_size: 516959
relation: main_file
file_date_updated: 2020-07-14T12:44:37Z
has_accepted_license: '1'
intvolume: ' 30'
isi: 1
issue: '4'
language:
- iso: eng
month: '10'
oa: 1
oa_version: Submitted Version
page: 1238 - 1275
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 Cryptology
publication_status: published
publisher: Springer
publist_id: '6166'
quality_controlled: '1'
related_material:
record:
- id: '3238'
relation: earlier_version
status: public
scopus_import: '1'
status: public
title: Efficient authentication from hard learning problems
type: journal_article
user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1
volume: 30
year: '2017'
...
---
_id: '1653'
abstract:
- lang: eng
text: "A somewhere statistically binding (SSB) hash, introduced by Hubáček and Wichs
(ITCS ’15), can be used to hash a long string x to a short digest y = H hk (x)
using a public hashing-key hk. Furthermore, there is a way to set up the hash
key hk to make it statistically binding on some arbitrary hidden position i, meaning
that: (1) the digest y completely determines the i’th bit (or symbol) of x so
that all pre-images of y have the same value in the i’th position, (2) it is computationally
infeasible to distinguish the position i on which hk is statistically binding
from any other position i’. Lastly, the hash should have a local opening property
analogous to Merkle-Tree hashing, meaning that given x and y = H hk (x) it should
be possible to create a short proof π that certifies the value of the i’th bit
(or symbol) of x without having to provide the entire input x. A similar primitive
called a positional accumulator, introduced by Koppula, Lewko and Waters (STOC
’15) further supports dynamic updates of the hashed value. These tools, which
are interesting in their own right, also serve as one of the main technical components
in several recent works building advanced applications from indistinguishability
obfuscation (iO).\r\n\r\nThe prior constructions of SSB hashing and positional
accumulators required fully homomorphic encryption (FHE) and iO respectively.
In this work, we give new constructions of these tools based on well studied number-theoretic
assumptions such as DDH, Phi-Hiding and DCR, as well as a general construction
from lossy/injective functions."
alternative_title:
- LNCS
author:
- first_name: Tatsuaki
full_name: Okamoto, Tatsuaki
last_name: Okamoto
- 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: Brent
full_name: Waters, Brent
last_name: Waters
- first_name: Daniel
full_name: Wichs, Daniel
last_name: Wichs
citation:
ama: 'Okamoto T, Pietrzak KZ, Waters B, Wichs D. New realizations of somewhere statistically
binding hashing and positional accumulators. In: Vol 9452. Springer; 2016:121-145.
doi:10.1007/978-3-662-48797-6_6'
apa: 'Okamoto, T., Pietrzak, K. Z., Waters, B., & Wichs, D. (2016). New realizations
of somewhere statistically binding hashing and positional accumulators (Vol. 9452,
pp. 121–145). Presented at the ASIACRYPT: Theory and Application of Cryptology
and Information Security, Auckland, New Zealand: Springer. https://doi.org/10.1007/978-3-662-48797-6_6'
chicago: Okamoto, Tatsuaki, Krzysztof Z Pietrzak, Brent Waters, and Daniel Wichs.
“New Realizations of Somewhere Statistically Binding Hashing and Positional Accumulators,”
9452:121–45. Springer, 2016. https://doi.org/10.1007/978-3-662-48797-6_6.
ieee: 'T. Okamoto, K. Z. Pietrzak, B. Waters, and D. Wichs, “New realizations of
somewhere statistically binding hashing and positional accumulators,” presented
at the ASIACRYPT: Theory and Application of Cryptology and Information Security,
Auckland, New Zealand, 2016, vol. 9452, pp. 121–145.'
ista: 'Okamoto T, Pietrzak KZ, Waters B, Wichs D. 2016. New realizations of somewhere
statistically binding hashing and positional accumulators. ASIACRYPT: Theory and
Application of Cryptology and Information Security, LNCS, vol. 9452, 121–145.'
mla: Okamoto, Tatsuaki, et al. New Realizations of Somewhere Statistically Binding
Hashing and Positional Accumulators. Vol. 9452, Springer, 2016, pp. 121–45,
doi:10.1007/978-3-662-48797-6_6.
short: T. Okamoto, K.Z. Pietrzak, B. Waters, D. Wichs, in:, Springer, 2016, pp.
121–145.
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: 2018-12-11T11:53:16Z
date_published: 2016-01-08T00:00:00Z
date_updated: 2021-01-12T06:52:16Z
day: '08'
ddc:
- '000'
department:
- _id: KrPi
doi: 10.1007/978-3-662-48797-6_6
ec_funded: 1
file:
- access_level: open_access
checksum: a57711cb660c5b17b42bb47275a00180
content_type: application/pdf
creator: system
date_created: 2018-12-12T10:12:05Z
date_updated: 2020-07-14T12:45:08Z
file_id: '4923'
file_name: IST-2016-677-v1+1_869.pdf
file_size: 580088
relation: main_file
file_date_updated: 2020-07-14T12:45:08Z
has_accepted_license: '1'
intvolume: ' 9452'
language:
- iso: eng
month: '01'
oa: 1
oa_version: Submitted Version
page: 121 - 145
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: '5497'
pubrep_id: '677'
quality_controlled: '1'
scopus_import: 1
status: public
title: New realizations of somewhere statistically binding hashing and positional
accumulators
type: conference
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 9452
year: '2016'
...
---
_id: '1479'
abstract:
- lang: eng
text: "Most entropy notions H(.) like Shannon or min-entropy satisfy a chain rule
stating that for random variables X,Z, and A we have H(X|Z,A)≥H(X|Z)−|A|. That
is, by conditioning on A the entropy of X can decrease by at most the bitlength
|A| of A. Such chain rules are known to hold for some computational entropy notions
like Yao’s and unpredictability-entropy. For HILL entropy, the computational analogue
of min-entropy, the chain rule is of special interest and has found many applications,
including leakage-resilient cryptography, deterministic encryption, and memory
delegation. These applications rely on restricted special cases of the chain rule.
Whether the chain rule for conditional HILL entropy holds in general was an open
problem for which we give a strong negative answer: we construct joint distributions
(X,Z,A), where A is a distribution over a single bit, such that the HILL entropy
H HILL (X|Z) is large but H HILL (X|Z,A) is basically zero.\r\n\r\nOur counterexample
just makes the minimal assumption that NP⊈P/poly. Under the stronger assumption
that injective one-way function exist, we can make all the distributions efficiently
samplable.\r\n\r\nFinally, we show that some more sophisticated cryptographic
objects like lossy functions can be used to sample a distribution constituting
a counterexample to the chain rule making only a single invocation to the underlying
object."
acknowledgement: "This work was partly funded by the European Research Council under
ERC Starting Grant 259668-PSPC and ERC Advanced Grant 321310-PERCY.\r\n"
author:
- first_name: Stephan
full_name: Krenn, Stephan
id: 329FCCF0-F248-11E8-B48F-1D18A9856A87
last_name: Krenn
orcid: 0000-0003-2835-9093
- 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: Akshay
full_name: Wadia, Akshay
last_name: Wadia
- first_name: Daniel
full_name: Wichs, Daniel
last_name: Wichs
citation:
ama: Krenn S, Pietrzak KZ, Wadia A, Wichs D. A counterexample to the chain rule
for conditional HILL entropy. Computational Complexity. 2016;25(3):567-605.
doi:10.1007/s00037-015-0120-9
apa: Krenn, S., Pietrzak, K. Z., Wadia, A., & Wichs, D. (2016). A counterexample
to the chain rule for conditional HILL entropy. Computational Complexity.
Springer. https://doi.org/10.1007/s00037-015-0120-9
chicago: Krenn, Stephan, Krzysztof Z Pietrzak, Akshay Wadia, and Daniel Wichs. “A
Counterexample to the Chain Rule for Conditional HILL Entropy.” Computational
Complexity. Springer, 2016. https://doi.org/10.1007/s00037-015-0120-9.
ieee: S. Krenn, K. Z. Pietrzak, A. Wadia, and D. Wichs, “A counterexample to the
chain rule for conditional HILL entropy,” Computational Complexity, vol.
25, no. 3. Springer, pp. 567–605, 2016.
ista: Krenn S, Pietrzak KZ, Wadia A, Wichs D. 2016. A counterexample to the chain
rule for conditional HILL entropy. Computational Complexity. 25(3), 567–605.
mla: Krenn, Stephan, et al. “A Counterexample to the Chain Rule for Conditional
HILL Entropy.” Computational Complexity, vol. 25, no. 3, Springer, 2016,
pp. 567–605, doi:10.1007/s00037-015-0120-9.
short: S. Krenn, K.Z. Pietrzak, A. Wadia, D. Wichs, Computational Complexity 25
(2016) 567–605.
date_created: 2018-12-11T11:52:16Z
date_published: 2016-09-01T00:00:00Z
date_updated: 2023-02-23T11:05:09Z
day: '01'
ddc:
- '004'
department:
- _id: KrPi
doi: 10.1007/s00037-015-0120-9
ec_funded: 1
file:
- access_level: open_access
checksum: 7659296174fa75f5f0364f31f46f4bcf
content_type: application/pdf
creator: system
date_created: 2018-12-12T10:13:29Z
date_updated: 2020-07-14T12:44:56Z
file_id: '5012'
file_name: IST-2017-766-v1+1_678.pdf
file_size: 483258
relation: main_file
file_date_updated: 2020-07-14T12:44:56Z
has_accepted_license: '1'
intvolume: ' 25'
issue: '3'
language:
- iso: eng
month: '09'
oa: 1
oa_version: Submitted Version
page: 567 - 605
project:
- _id: 258C570E-B435-11E9-9278-68D0E5697425
call_identifier: FP7
grant_number: '259668'
name: Provable Security for Physical Cryptography
publication: Computational Complexity
publication_status: published
publisher: Springer
publist_id: '5715'
pubrep_id: '766'
quality_controlled: '1'
related_material:
record:
- id: '2940'
relation: earlier_version
status: public
scopus_import: 1
status: public
title: A counterexample to the chain rule for conditional HILL entropy
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: 3E5EF7F0-F248-11E8-B48F-1D18A9856A87
volume: 25
year: '2016'
...
---
_id: '1366'
abstract:
- lang: eng
text: 'We study the problem of devising provably secure PRNGs with input based on
the sponge paradigm. Such constructions are very appealing, as efficient software/hardware
implementations of SHA-3 can easily be translated into a PRNG in a nearly black-box
way. The only existing sponge-based construction, proposed by Bertoni et al. (CHES
2010), fails to achieve the security notion of robustness recently considered
by Dodis et al. (CCS 2013), for two reasons: (1) The construction is deterministic,
and thus there are high-entropy input distributions on which the construction
fails to extract random bits, and (2) The construction is not forward secure,
and presented solutions aiming at restoring forward security have not been rigorously
analyzed. We propose a seeded variant of Bertoni et al.’s PRNG with input which
we prove secure in the sense of robustness, delivering in particular concrete
security bounds. On the way, we make what we believe to be an important conceptual
contribution, developing a variant of the security framework of Dodis et al. tailored
at the ideal permutation model that captures PRNG security in settings where the
weakly random inputs are provided from a large class of possible adversarial samplers
which are also allowed to query the random permutation. As a further application
of our techniques, we also present an efficient sponge-based key-derivation function
(which can be instantiated from SHA-3 in a black-box fashion), which we also prove
secure when fed with samples from permutation-dependent distributions.'
alternative_title:
- LNCS
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. Provably robust sponge-based PRNGs and KDFs. In: Vol 9665.
Springer; 2016:87-116. doi:10.1007/978-3-662-49890-3_4'
apa: 'Gazi, P., & Tessaro, S. (2016). Provably robust sponge-based PRNGs and
KDFs (Vol. 9665, pp. 87–116). Presented at the EUROCRYPT: Theory and Applications
of Cryptographic Techniques, Vienna, Austria: Springer. https://doi.org/10.1007/978-3-662-49890-3_4'
chicago: Gazi, Peter, and Stefano Tessaro. “Provably Robust Sponge-Based PRNGs and
KDFs,” 9665:87–116. Springer, 2016. https://doi.org/10.1007/978-3-662-49890-3_4.
ieee: 'P. Gazi and S. Tessaro, “Provably robust sponge-based PRNGs and KDFs,” presented
at the EUROCRYPT: Theory and Applications of Cryptographic Techniques, Vienna,
Austria, 2016, vol. 9665, pp. 87–116.'
ista: 'Gazi P, Tessaro S. 2016. Provably robust sponge-based PRNGs and KDFs. EUROCRYPT:
Theory and Applications of Cryptographic Techniques, LNCS, vol. 9665, 87–116.'
mla: Gazi, Peter, and Stefano Tessaro. Provably Robust Sponge-Based PRNGs and
KDFs. Vol. 9665, Springer, 2016, pp. 87–116, doi:10.1007/978-3-662-49890-3_4.
short: P. Gazi, S. Tessaro, in:, Springer, 2016, pp. 87–116.
conference:
end_date: 2016-05-12
location: Vienna, Austria
name: 'EUROCRYPT: Theory and Applications of Cryptographic Techniques'
start_date: 2016-05-08
date_created: 2018-12-11T11:51:36Z
date_published: 2016-05-01T00:00:00Z
date_updated: 2021-01-12T06:50:11Z
day: '01'
department:
- _id: KrPi
doi: 10.1007/978-3-662-49890-3_4
ec_funded: 1
intvolume: ' 9665'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://eprint.iacr.org/2016/169/20160219:201940
month: '05'
oa: 1
oa_version: Preprint
page: 87 - 116
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: '5872'
quality_controlled: '1'
scopus_import: 1
status: public
title: Provably robust sponge-based PRNGs and KDFs
type: conference
user_id: 3E5EF7F0-F248-11E8-B48F-1D18A9856A87
volume: 9665
year: '2016'
...
---
_id: '1225'
abstract:
- lang: eng
text: At Crypto 2015 Fuchsbauer, Hanser and Slamanig (FHS) presented the first standard-model
construction of efficient roundoptimal blind signatures that does not require
complexity leveraging. It is conceptually simple and builds on the primitive of
structure-preserving signatures on equivalence classes (SPS-EQ). FHS prove the
unforgeability of their scheme assuming EUF-CMA security of the SPS-EQ scheme
and hardness of a version of the DH inversion problem. Blindness under adversarially
chosen keys is proven under an interactive variant of the DDH assumption. We propose
a variant of their scheme whose blindness can be proven under a non-interactive
assumption, namely a variant of the bilinear DDH assumption. We moreover prove
its unforgeability assuming only unforgeability of the underlying SPS-EQ but no
additional assumptions as needed for the FHS scheme.
alternative_title:
- LNCS
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: Chethan
full_name: Kamath Hosdurg, Chethan
id: 4BD3F30E-F248-11E8-B48F-1D18A9856A87
last_name: Kamath Hosdurg
- first_name: Daniel
full_name: Slamanig, Daniel
last_name: Slamanig
citation:
ama: 'Fuchsbauer G, Hanser C, Kamath Hosdurg C, Slamanig D. Practical round-optimal
blind signatures in the standard model from weaker assumptions. In: Vol 9841.
Springer; 2016:391-408. doi:10.1007/978-3-319-44618-9_21'
apa: 'Fuchsbauer, G., Hanser, C., Kamath Hosdurg, C., & Slamanig, D. (2016).
Practical round-optimal blind signatures in the standard model from weaker assumptions
(Vol. 9841, pp. 391–408). Presented at the SCN: Security and Cryptography for
Networks, Amalfi, Italy: Springer. https://doi.org/10.1007/978-3-319-44618-9_21'
chicago: Fuchsbauer, Georg, Christian Hanser, Chethan Kamath Hosdurg, and Daniel
Slamanig. “Practical Round-Optimal Blind Signatures in the Standard Model from
Weaker Assumptions,” 9841:391–408. Springer, 2016. https://doi.org/10.1007/978-3-319-44618-9_21.
ieee: 'G. Fuchsbauer, C. Hanser, C. Kamath Hosdurg, and D. Slamanig, “Practical
round-optimal blind signatures in the standard model from weaker assumptions,”
presented at the SCN: Security and Cryptography for Networks, Amalfi, Italy, 2016,
vol. 9841, pp. 391–408.'
ista: 'Fuchsbauer G, Hanser C, Kamath Hosdurg C, Slamanig D. 2016. Practical round-optimal
blind signatures in the standard model from weaker assumptions. SCN: Security
and Cryptography for Networks, LNCS, vol. 9841, 391–408.'
mla: Fuchsbauer, Georg, et al. Practical Round-Optimal Blind Signatures in the
Standard Model from Weaker Assumptions. Vol. 9841, Springer, 2016, pp. 391–408,
doi:10.1007/978-3-319-44618-9_21.
short: G. Fuchsbauer, C. Hanser, C. Kamath Hosdurg, D. Slamanig, in:, Springer,
2016, pp. 391–408.
conference:
end_date: 2016-09-02
location: Amalfi, Italy
name: 'SCN: Security and Cryptography for Networks'
start_date: 2016-08-31
date_created: 2018-12-11T11:50:49Z
date_published: 2016-08-11T00:00:00Z
date_updated: 2023-02-23T10:08:16Z
day: '11'
department:
- _id: KrPi
doi: 10.1007/978-3-319-44618-9_21
ec_funded: 1
intvolume: ' 9841'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://eprint.iacr.org/2016/662
month: '08'
oa: 1
oa_version: Submitted Version
page: 391 - 408
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: '6109'
quality_controlled: '1'
related_material:
record:
- id: '1647'
relation: earlier_version
status: public
scopus_import: 1
status: public
title: Practical round-optimal blind signatures in the standard model from weaker
assumptions
type: conference
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 9841
year: '2016'
...
---
_id: '1229'
abstract:
- lang: eng
text: Witness encryption (WE) was introduced by Garg et al. [GGSW13]. A WE scheme
is defined for some NP language L and lets a sender encrypt messages relative
to instances x. A ciphertext for x can be decrypted using w witnessing x ∈ L,
but hides the message if x ∈ L. Garg et al. construct WE from multilinear maps
and give another construction [GGH+13b] using indistinguishability obfuscation
(iO) for circuits. Due to the reliance on such heavy tools, WE can cur- rently
hardly be implemented on powerful hardware and will unlikely be realizable on
constrained devices like smart cards any time soon. We construct a WE scheme where
encryption is done by simply computing a Naor-Yung ciphertext (two CPA encryptions
and a NIZK proof). To achieve this, our scheme has a setup phase, which outputs
public parameters containing an obfuscated circuit (only required for decryption),
two encryption keys and a common reference string (used for encryption). This
setup need only be run once, and the parame- ters can be used for arbitrary many
encryptions. Our scheme can also be turned into a functional WE scheme, where
a message is encrypted w.r.t. a statement and a function f, and decryption with
a witness w yields f (m, w). Our construction is inspired by the functional encryption
scheme by Garg et al. and we prove (selective) security assuming iO and statistically
simulation-sound NIZK. We give a construction of the latter in bilinear groups
and combining it with ElGamal encryption, our ciphertexts are of size 1.3 kB at
a 128-bit security level and can be computed on a smart card.
acknowledgement: 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
- 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. Offline witness encryption. In: Vol
9696. Springer; 2016:285-303. doi:10.1007/978-3-319-39555-5_16'
apa: 'Abusalah, H. M., Fuchsbauer, G., & Pietrzak, K. Z. (2016). Offline witness
encryption (Vol. 9696, pp. 285–303). Presented at the ACNS: Applied Cryptography
and Network Security, Guildford, UK: Springer. https://doi.org/10.1007/978-3-319-39555-5_16'
chicago: Abusalah, Hamza M, Georg Fuchsbauer, and Krzysztof Z Pietrzak. “Offline
Witness Encryption,” 9696:285–303. Springer, 2016. https://doi.org/10.1007/978-3-319-39555-5_16.
ieee: 'H. M. Abusalah, G. Fuchsbauer, and K. Z. Pietrzak, “Offline witness encryption,”
presented at the ACNS: Applied Cryptography and Network Security, Guildford, UK,
2016, vol. 9696, pp. 285–303.'
ista: 'Abusalah HM, Fuchsbauer G, Pietrzak KZ. 2016. Offline witness encryption.
ACNS: Applied Cryptography and Network Security, LNCS, vol. 9696, 285–303.'
mla: Abusalah, Hamza M., et al. Offline Witness Encryption. Vol. 9696, Springer,
2016, pp. 285–303, doi:10.1007/978-3-319-39555-5_16.
short: H.M. Abusalah, G. Fuchsbauer, K.Z. Pietrzak, in:, Springer, 2016, pp. 285–303.
conference:
end_date: 2016-06-22
location: Guildford, UK
name: 'ACNS: Applied Cryptography and Network Security'
start_date: 2016-06-19
date_created: 2018-12-11T11:50:50Z
date_published: 2016-06-09T00:00:00Z
date_updated: 2023-09-07T12:30:22Z
day: '09'
ddc:
- '005'
- '600'
department:
- _id: KrPi
doi: 10.1007/978-3-319-39555-5_16
ec_funded: 1
file:
- access_level: open_access
checksum: 34fa9ce681da845a1ba945ba3dc57867
content_type: application/pdf
creator: system
date_created: 2018-12-12T10:17:20Z
date_updated: 2020-07-14T12:44:39Z
file_id: '5273'
file_name: IST-2017-765-v1+1_838.pdf
file_size: 515000
relation: main_file
file_date_updated: 2020-07-14T12:44:39Z
has_accepted_license: '1'
intvolume: ' 9696'
language:
- iso: eng
month: '06'
oa: 1
oa_version: Submitted Version
page: 285 - 303
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: '6105'
pubrep_id: '765'
quality_controlled: '1'
related_material:
record:
- id: '83'
relation: dissertation_contains
status: public
scopus_import: 1
status: public
title: Offline witness encryption
type: conference
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 9696
year: '2016'
...
---
_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
license: https://creativecommons.org/licenses/by-nc/4.0/
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'
...