IACR News
Here you can see all recent updates to the IACR webpage. These updates are also available:
01 August 2019
Daan Leermakers, Boris Skoric
ePrint ReportFei Meng, Mingqiang Wang
ePrint ReportPrivacy and efficiency issues haven't been fully considered, therefore we provide a construction of ABFKS with privacy preserving, efficient attribute update and reverse outsourcing (ABKFS-PER). To be specific, we provide a novel method to protect the privacy of access structure by replacing each leaf node with an OR gate. In this scheme, every user has all the attributes in the cloud's view by adding fake ones so to protect the privacy of user authority. We propose a new method for attribute update, in which the key authority center only updates the user who needs update, not everyone. At last, we initially propose the concept of reverse outsourcing, namely the cloud outsourcing computational tasks to idle users to reduce its overhead.
Shashi Kant Pandey, P.R. Mishra
ePrint Report30 July 2019
Mark Abspoel, Ronald Cramer, Ivan Damgård, Daniel Escudero, Chen Yuan
ePrint ReportClaude Crépeau, Nan Yang
ePrint ReportMarc Joye, Oleksandra Lapiha, Ky Nguyen, David Naccache
ePrint ReportAritra Dhar, Enis Ulqinaku, Kari Kostiainen, Srdjan Capkun
ePrint ReportRan Cohen, Iftach Haitner, Nikolaos Makriyannis, Matan Orland, Alex Samorodnitsky
ePrint Report(1) BA protocols resilient against $n/3$ [resp., $n/4$] corruptions terminate (under attack) at the end of the first round with probability at most $o(1)$ [resp., $1/2+ o(1)$].
(2) BA protocols resilient against n/4 corruptions terminate at the end of the second round with probability at most $1-\Theta(1)$.
(3) For a large class of protocols (including all BA protocols used in practice) and under a plausible combinatorial conjecture, BA protocols resilient against $n/3$ [resp., $n/4$] corruptions terminate at the end of the second round with probability at most $o(1)$ [resp., $1/2 + o(1)$].
The above bounds hold even when the parties use a trusted setup phase, e.g., a public-key infrastructure (PKI).
The third bound essentially matches the recent protocol of Micali (ITCS'17) that tolerates up to $n/3$ corruptions and terminates at the end of the third round with constant probability.
25 July 2019
Orr Dunkelman, Nathan Keller, Eran Lambooij, Yu Sasaki
ePrint ReportIn this note we present an extremely efficient forgery attack on Lilliput-AE: Given a single arbitrary message of length about 2^36 bytes, we can instantly produce another valid message that leads to the same tag, along with the corresponding ciphertext. The attack uses a weakness in the tweakey schedule of Lilliput-AE which leads to the existence of a related tweak differential characteristic with probability 1 in the underlying block cipher. The weakness we exploit, which does not exist in Lilliput, demonstrates the potential security risk in using a very simple tweakey schedule in which the same part of the key/tweak is re-used in every round, even when round constants are employed to prevent slide attacks. Following this attack, the Lilliput-AE submission to NIST was tweaked.
Lichao Wu, Gerard Ribera, Stjepan Picek
ePrint ReportLe He, Hongbo Yu
ePrint ReportYongge Wang
ePrint ReportMegha Byali, Carmit Hazay, Arpita Patra, Swati Singla
ePrint ReportIn a minimal setting of pairwise-private channels, we present efficient instantiations with unanimous abort (where either all honest parties obtain the output or none of them do) and fairness (where the adversary obtains its output only if all honest parties also receive it). With the presence of an additional broadcast channel (known to be necessary), we present a construction with guaranteed output delivery (where any adversarial behaviour cannot prevent the honest parties from receiving the output). The broadcast communication is minimal and independent of circuit size. In terms of performance (communication and run time), our protocols incur minimal overhead over the best known selective abort protocol of Chandran et al. (ACM CCS 2016) while retaining their round complexity.
Further, our protocols for fairness and unanimous abort can be extended to n-parties with at most $\sqrt{n}$ corruptions, similar to Chandran et al. Going beyond the most popular honest-majority setting of three parties with one corruption, our results demonstrate feasibility of attaining stronger security notions at an expense not too far from the least desired security of selective abort.
Dmitry Khovratovich
ePrint Report24 July 2019
Gabrielle De Micheli, Rémi Piau, Cécile Pierrot
ePrint ReportYongbo Hu, Yeyang Zheng, Pengwei Feng, Lirui Liu, Chen Zhang, Aron Gohr, Sven Jacob, Werner Schindler, Ileana Buhan, Karim Tobich
ePrint ReportKyosuke Yamashita, Mehdi Tibouchi, Masayuki Abe
ePrint ReportEric Crockett, Christian Paquin, Douglas Stebila
ePrint ReportFirst, we examine various design considerations for integrating post-quantum and hybrid key exchange and authentication into communications protocols generally, and in TLS and SSH specifically. These include issues such as how to negotiate the use of multiple algorithms for hybrid cryptography, how to combine multiple keys, and more. Subsequently, we report on several implementations of post-quantum and hybrid key exchange in TLS 1.2, TLS 1.3, and SSHv2. We also report on work to add hybrid authentication in TLS 1.3 and SSHv2. These integrations are in Amazon s2n and forks of OpenSSL and OpenSSH; the latter two rely on the liboqs library from the Open Quantum Safe project.
Announcement
The program will include sessions on design and analysis of symmetric key primitives, efficient implementations, mathematical cryptology, real-world cryptography, and post-quantum crypto. Details and program at https://uwaterloo.ca/sac-2019.
Some stipends available to help support attendance of students and early career researchers.
CHES
Atlanta, GA, August 25-28, 2019
https://ches.iacr.org/2019/
The Cryptographic Hardware and Embedded Systems (CHES) conference is the premier venue for research on design and evaluation of cryptographic implementations and secure embedded systems. CHES 2019 marks the 20th anniversary of the CHES conference and will take place in the city of Atlanta, U.S.A., August 25–28, 2019, immediately following CRYPTO 2019.
Due to a recent health hazard with Sheraton Atlanta, CHES 2019 will change its venue to the nearby Westin Peachtree Plaza. Please find updated information below regarding registration and hotel booking.
Registration
CHES 2019 registrations are open at https://ches.iacr.org/2019/registration.shtml
The early registration deadline has been extended from July 24, 2019 to Aug. 7th, 2019 to accommodate the venue change.
Hotel
The conference venue is the Westin Peachtree Plaza, a 70th-floor prime location in downtown Atlanta. The hotel provides a time-limited block rate to CHES 2019 attendees until Aug. 7th, 2019, 5pm (EST).
Book a hotel room at the regular CHES 2019 rate ($159/night and up)
Please let us know in your registration form if you plan to stay at the Westin.
For people who have made hotel reservation with Sheraton Atlanta, please follow the guidelines on the CHES 2019 venue page for actions to adapt.
Program
CHES 2019 offers a broad collection of events:
- Three days of conference with top-notch paper presentations, with papers accepted and published by TCHES
- Two invited keynote talks
- Six half-day tutorials by experts in the field
- Two co-located pre-conference events, FDTC and PROOFS
- A banquet at Sundial Restaurant, situated on the uppermost floors of the Westin Peachtree Plaza
- A social event at the Martin Luther King National Historical Park
CHES 2019 is organized in Downtown Atlanta and is easily reachable from the Atlanta International Airport (ATL). Consult the CHES 2019 Travel Information Page for additional guidelines.