IACR News
Here you can see all recent updates to the IACR webpage. These updates are also available:
17 September 2015
Yannick Seurin
ePrint Report
Junqing Gong, Xiaolei Dong, Zhenfu Cao, Jie Chen
ePrint Report
Yuval Yarom, Qian Ge, Fangfei Liu, Ruby B. Lee, Gernot Heiser
ePrint Report
Adnan Baysal, Suhap Sahin
ePrint ReportCPUs is a challenging problem. There are many recent lightweight ciphers designed for better performance in hardware. On the other hand, most software efficient lightweight ciphers either lack a security proof or have a low security margin. To fill the gap, we present RoadRunneR which is an efficient block cipher in 8-bit software, and its security is provable against differential and linear attacks. RoadRunneR has lowest code size in Atmel\'s ATtiny45, except NSA\'s design SPECK, which has no security proof. Moreover, we propose a new metric for the fair comparison of block ciphers. This metric, called ST/A, is the first metric to
use key length as a parameter to rank ciphers of different key length in a fair way. By using ST/A and other metrics in the literature, we show that RoadRunneR is competitive among existing ciphers on ATtiny45.
Shafi Goldwasser, Yael Tauman Kalai
ePrint Reportwe utilize should be of significant substance, and serve as the yard stick for the value of our proposals.
Lately, the field of cryptography has seen a sharp increase in the number of new assumptions that are often complex to define and difficult to interpret. At times, these assumptions are hard to untangle from the constructions which utilize them.
We believe that the lack of standards of what is accepted as a reasonable cryptographic assumption can be harmful to the credibility of our field. Therefore, there is a great need for measures according to which we classify and compare assumptions, as to which are safe and which are not. In this paper, we propose such a classification and review recently suggested assumptions in this light. This follows the footsteps of Naor (Crypto 2003).
Martin M. Lauridsen, Christian Rechberger
ePrint ReportCombining our model with ideas from message modification and rebound-like approaches, we initiate a study of cryptographic primitives with respect to this new attack vector and choose the lightweight block cipher PRESENT as an example target. This leads to known-key distinguishers over up to 27 rounds, whereas the best previous result is up to 18 rounds in the chosen-key model.
Bart Mennink, Bart Preneel
ePrint Report
Alonso González, Alejandro Hevia, Carla Ràfols
ePrint ReportIn this paper we develop specific techniques for asymmetric groups. We introduce a new computational assumption, under which we can recover all the aggregation results of Groth- Sahai proofs known in the symmetric setting. We adapt the arguments of membership in linear spaces of $G^m$ to linear subspaces of $G^m \\times H^n . In particular, we give a constant-size argument that two sets of Groth-Sahai commitments, defined over different groups $G$, $H$, open to the same scalars in $Z_q$, a useful tool to prove satisfiability of quadratic equations in $Z_q$. We then use one of the arguments for subspaces in $G^m \\times H^n$ and develop new techniques to give constant-size QA-NIZK proofs that a commitment opens to a bit-string. To the best of our knowledge, these are the first constant-size proofs for quadratic equations in $Z_q$ under standard and falsifiable assumptions. As a result, we obtain improved threshold Groth-Sahai proofs for pairing product equations, ring signatures, proofs of membership in a list, and various types of signature schemes.
16 September 2015
Hyderabad, India, September 28 - September 30
Event CalendarNotification: 30 September 2015
From September 28 to September 30
Location: Hyderabad, India
More Information: https://docs.google.com/forms/d/1KiT3ZU_qYucqM1-F_xAx-5VwatXyBfqAGIFsNlEO9Hw/viewform?c=0&w=1
Xi'an, China, March 30
Event CalendarNotification: 15 February 2016
From March 30 to March 30
Location: Xi'an, China
More Information: http://www2.nict.go.jp/nsri/fund/asiapkc2016/
Mehmet Sinan Inci, Berk Gulmezoglu, Gorka Irazoqui, Thomas Eisenbarth, Berk Sunar
ePrint Report
Payal Chaudhari, Maniklal Das
ePrint Reportcryptographic primitive that can be used for cryptographically enforced access control in untrusted storage. Storing data on untrusted storage not only requires data security for data owners but also poses data protection from untrusted storage server. To address this important requirement, Anonymous Attribute Based Encryption (AABE) is a suitable primitive that provides users to access data from untrusted storage without revealing their identities. At the same time user data can be stored in untrusted storage in an encrypted form. While storing data in an encrypted
form, keyword-based query search (and data retrieval) is a challenging research problem. In this paper we present an anonymous attribute based searchable encryption (A2SBE) scheme which facilitates user to retrieve only a subset of documents pertaining to his chosen keyword(s). User can upload documents in public cloud in an encrypted form, search documents based on keyword(s) and retrieve documents without revealing his identity. The scheme is proven secure under the selective ciphertext-
policy and chosen plaintext attack (IND-sCP-CPA) model and selective ciphertext-policy and chosen keyword attack (IND-sCP-CKA) model. The scheme requires small storage for user\'s decryption key and reduced computation for decryption in comparison to other schemes.
Ferucio Laurentiu Tiplea, Emil Simion
ePrint Report
Tore Kasper Frederiksen, Marcel Keller, Emmanuela Orsini, Peter Scholl
ePrint Reportproduces multiplication triples in a finite field. This work describes new protocols for generating multiplication triples in fields of characteristic two using OT extensions. Before this work, TinyOT, which works on binary circuits, was the only protocol in this family using OT extensions.
Previous SPDZ protocols for triples in large finite fields require somewhat homomorphic encryption, which leads to very inefficient runtimes in practice, while no dedicated preprocessing protocol for MiniMAC (which operates on vectors of small field elements) was previously known. Since actively secure OT extensions can be performed very efficiently using only symmetric primitives, it is highly desirable to base MPC protocols on these rather than expensive public key primitives. We analyze the practical efficiency of our protocols, showing that they should all perform favorably compared with previous works; we estimate our protocol for SPDZ triples in $\\mathbb{F}_{2^{40}}$ will perform around 2 orders of magnitude faster
than the best known previous protocol.
15 September 2015
Tacoma, USA, August 9 - August 12
Event CalendarNotification: 2 May 2016
From August 9 to August 12
Location: Tacoma, USA
More Information: http://www.icits2016.com
Wenbin Zhang, Chik How Tan
ePrint Report
S\\\'ebastien Canard, Viet Cuong Trinh
ePrint ReportIn this paper, we give the first private CP-ABE constructions with a constant-size ciphertext, supporting CNF (Conjunctive Normal Form) access policy, with the simple restriction that each attribute can only appear $k_{max}$ times in the access formula. Our two constructions are based on the BGW scheme at Crypto\'05. The first scheme is basic selective secure (in the standard model) while our second one reaches the selective CCA security (in the random oracle model).
Kenneth G. Paterson, Jacob C. N. Schuldt, Dale L. Sibborn, Hoeteck Wee
ePrint Report
Christian Badertscher, Christian Matt, Ueli Maurer, Phillip Rogaway, Björn Tackmann
ePrint ReportMoreover, we provide a rigorous treatment of two previously only informally stated additional features of RAE; namely, we show how redundancy in the message space can be exploited to improve the security and we analyze the exact security loss if multiple messages are encrypted with the same nonce.
Richard Winter, Ana Salagean, Raphael C.-W. Phan
ePrint Report