---
OA_place: repository
OA_type: green
_id: '20845'
abstract:
- lang: eng
text: "We develop new attacks against the Evasive LWE family of assumptions, in
both the public and private-coin regime. To the best of our knowledge, ours are
the first attacks against Evasive LWE in the public-coin regime, for any instantiation
from the family. Our attacks are summarized below.\r\n\r\nPublic-Coin Attacks.\r\n1.The
recent work by Hseih, Lin and Luo [17] constructed the first Attribute Based Encryption
(ABE) for unbounded depth circuits by relying on the “circular” evasive LWE assumption.
This assumption has been popularly considered as a safe, public-coin instance
of Evasive LWE in contrast to its “private-coin” cousins (for instance, see [10,
11]).\r\nWe provide the first attack against this assumption, challenging the
widely held belief that this is a public-coin assumption.\r\n2. We demonstrate
a counter-example against vanilla public-coin evasive LWE by Wee [26] in an unnatural
parameter regime. Our attack crucially relies on the error in the pre-condition
being larger than the error in the post-condition, necessitating a refinement
of the assumption.\r\n\r\nPrivate-Coin Attacks.\r\n1. The recent work by Agrawal,
Kumari and Yamada [2] constructed the first functional encryption scheme for pseudorandom
functionalities (PRFE) and extended this to obfuscation for pseudorandom functionalities
(PRIO) [4] by relying on private-coin evasive LWE. We provide a new attack against
the assumption stated in the first posting of their work (subsequently refined
to avoid these attacks).\r\n2. The recent work by Branco et al. [8] (concurrently
to [4]) provides a construction of obfuscation for pseudorandom functionalities
by relying on private-coin evasive LWE. We provide a new attack against their
stated assumption.\r\n3. Branco et al. [8] showed that there exist contrived,
“self-referential” classes of pseudorandom functionalities for which pseudorandom
obfuscation cannot exist. We extend their techniques to develop an analogous result
for pseudorandom functional encryption.\r\n\r\nWhile Evasive LWE was developed
to specifically avoid “zeroizing attacks”, our work shows that in certain settings,
such attacks can still apply."
acknowledgement: "We thank Rachel Lin for expressing concern about the applicability
of “HJL-style” attacks [15] on the construction in [2] during a talk by the first
author about [2]. This was the starting point of the investigation that led us to
develop the attack in [5, Sec 4.1]. The first author also thanks Hoeteck Wee for
sharing his rationale for introducing evasive LWE.\r\nThe first author is supported
by the CyStar center of excellence, the VHAR faculty chair, and the C3iHub fellowship.
The third author thanks Cystar, IIT Madras, for supporting a visit to IIT Madras
during which the collaboration was initiated. The 4th author is partly supported
by JST CREST Grant Number JPMJCR22M1."
alternative_title:
- LNCS
article_processing_charge: No
author:
- first_name: Shweta
full_name: Agrawal, Shweta
last_name: Agrawal
- first_name: Anuja
full_name: Modi, Anuja
last_name: Modi
- first_name: Anshu
full_name: Yadav, Anshu
id: dc8f1524-403e-11ee-bf07-9649ad996e21
last_name: Yadav
- first_name: Shota
full_name: Yamada, Shota
last_name: Yamada
citation:
ama: 'Agrawal S, Modi A, Yadav A, Yamada S. Zeroizing attacks against evasive and circular
evasive LWE. In: 23rd International Conference on Theory of Cryptography.
Vol 16269. Springer Nature; 2025:259-290. doi:10.1007/978-3-032-12293-3_9'
apa: 'Agrawal, S., Modi, A., Yadav, A., & Yamada, S. (2025). Zeroizing attacks
against evasive and circular evasive LWE. In 23rd International Conference
on Theory of Cryptography (Vol. 16269, pp. 259–290). Aarhus, Denmark: Springer
Nature. https://doi.org/10.1007/978-3-032-12293-3_9'
chicago: Agrawal, Shweta, Anuja Modi, Anshu Yadav, and Shota Yamada. “Zeroizing
Attacks against Evasive and Circular Evasive LWE.” In 23rd International Conference
on Theory of Cryptography, 16269:259–90. Springer Nature, 2025. https://doi.org/10.1007/978-3-032-12293-3_9.
ieee: S. Agrawal, A. Modi, A. Yadav, and S. Yamada, “Zeroizing attacks against evasive
and circular evasive LWE,” in 23rd International Conference on Theory of Cryptography,
Aarhus, Denmark, 2025, vol. 16269, pp. 259–290.
ista: 'Agrawal S, Modi A, Yadav A, Yamada S. 2025. Zeroizing attacks against evasive
and circular evasive LWE. 23rd International Conference on Theory of Cryptography.
TCC: Theory of Cryptography, LNCS, vol. 16269, 259–290.'
mla: Agrawal, Shweta, et al. “Zeroizing Attacks against Evasive and Circular Evasive
LWE.” 23rd International Conference on Theory of Cryptography, vol. 16269,
Springer Nature, 2025, pp. 259–90, doi:10.1007/978-3-032-12293-3_9.
short: S. Agrawal, A. Modi, A. Yadav, S. Yamada, in:, 23rd International Conference
on Theory of Cryptography, Springer Nature, 2025, pp. 259–290.
conference:
end_date: 2025-12-05
location: Aarhus, Denmark
name: 'TCC: Theory of Cryptography'
start_date: 2025-12-01
date_created: 2025-12-21T23:01:33Z
date_published: 2025-12-05T00:00:00Z
date_updated: 2025-12-29T11:51:13Z
day: '05'
department:
- _id: KrPi
doi: 10.1007/978-3-032-12293-3_9
intvolume: ' 16269'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://eprint.iacr.org/2025/375
month: '12'
oa: 1
oa_version: Preprint
page: 259-290
publication: 23rd International Conference on Theory of Cryptography
publication_identifier:
eissn:
- 1611-3349
isbn:
- '9783032122926'
issn:
- 0302-9743
publication_status: published
publisher: Springer Nature
quality_controlled: '1'
scopus_import: '1'
status: public
title: Zeroizing attacks against evasive and circular evasive LWE
type: conference
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 16269
year: '2025'
...
---
OA_place: repository
OA_type: green
_id: '18755'
abstract:
- lang: eng
text: "A universalthresholdizer (UT), constructed from a threshold fully homomorphic
encryption by Boneh et. al , Crypto 2018, is a general framework for universally
thresholdizing many cryptographic schemes. However, their framework is insufficient
to construct strongly secure threshold schemes, such as threshold signatures and
threshold public-key encryption, etc.\r\n\r\nIn this paper, we strengthen the
security definition for a universal thresholdizer and propose a scheme which satisfies
our stronger security notion. Our UT scheme is an improvement of Boneh et. al
’s construction at the level of threshold fully homomorphic encryption using a
key homomorphic pseudorandom function. We apply our strongly secure UT scheme
to construct strongly secure threshold signatures and threshold public-key encryption."
acknowledgement: Ehsan Ebrahimi is supported by the Luxembourg National Research Fund
under the Junior CORE project QSP (C22/IS/17272217/QSP/Ebrahimi).
article_processing_charge: No
author:
- first_name: Ehsan
full_name: Ebrahimi, Ehsan
last_name: Ebrahimi
- first_name: Anshu
full_name: Yadav, Anshu
id: dc8f1524-403e-11ee-bf07-9649ad996e21
last_name: Yadav
citation:
ama: 'Ebrahimi E, Yadav A. Strongly secure universal thresholdizer. In: 30th
International Conference on the Theory and Application of Cryptology and Information
Security. Vol 15486. Springer Nature; 2024:207-239. doi:10.1007/978-981-96-0891-1_7'
apa: 'Ebrahimi, E., & Yadav, A. (2024). Strongly secure universal thresholdizer.
In 30th International Conference on the Theory and Application of Cryptology
and Information Security (Vol. 15486, pp. 207–239). Kolkata, India: Springer
Nature. https://doi.org/10.1007/978-981-96-0891-1_7'
chicago: Ebrahimi, Ehsan, and Anshu Yadav. “Strongly Secure Universal Thresholdizer.”
In 30th International Conference on the Theory and Application of Cryptology
and Information Security, 15486:207–39. Springer Nature, 2024. https://doi.org/10.1007/978-981-96-0891-1_7.
ieee: E. Ebrahimi and A. Yadav, “Strongly secure universal thresholdizer,” in 30th
International Conference on the Theory and Application of Cryptology and Information
Security, Kolkata, India, 2024, vol. 15486, pp. 207–239.
ista: 'Ebrahimi E, Yadav A. 2024. Strongly secure universal thresholdizer. 30th
International Conference on the Theory and Application of Cryptology and Information
Security. ASIACRYPT: Conference on the Theory and Application of Cryptology and
Information Security vol. 15486, 207–239.'
mla: Ebrahimi, Ehsan, and Anshu Yadav. “Strongly Secure Universal Thresholdizer.”
30th International Conference on the Theory and Application of Cryptology and
Information Security, vol. 15486, Springer Nature, 2024, pp. 207–39, doi:10.1007/978-981-96-0891-1_7.
short: E. Ebrahimi, A. Yadav, in:, 30th International Conference on the Theory and
Application of Cryptology and Information Security, Springer Nature, 2024, pp.
207–239.
conference:
end_date: 2024-12-13
location: Kolkata, India
name: 'ASIACRYPT: Conference on the Theory and Application of Cryptology and Information
Security'
start_date: 2024-12-09
date_created: 2025-01-05T23:01:56Z
date_published: 2024-12-12T00:00:00Z
date_updated: 2025-09-09T12:00:12Z
day: '12'
department:
- _id: KrPi
doi: 10.1007/978-981-96-0891-1_7
external_id:
isi:
- '001443889100007'
intvolume: ' 15486'
isi: 1
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://eprint.iacr.org/2024/2078
month: '12'
oa: 1
oa_version: Preprint
page: 207-239
publication: 30th International Conference on the Theory and Application of Cryptology
and Information Security
publication_identifier:
eissn:
- 1611-3349
isbn:
- '9789819608904'
issn:
- 0302-9743
publication_status: published
publisher: Springer Nature
quality_controlled: '1'
scopus_import: '1'
status: public
title: Strongly secure universal thresholdizer
type: conference
user_id: 317138e5-6ab7-11ef-aa6d-ffef3953e345
volume: 15486
year: '2024'
...