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01:17 [Pub][ePrint] Differential Fault Attack on the PRINCE Block Cipher, by Ling Song and Lei Hu

  PRINCE is a new lightweight block cipher proposed at the ASIACRYPT\'2012 conference. In this paper two observations on the linear layer of the cipher are presented. Based on the observations a differential fault attack is applied to the cipher under a random nibble-level fault model. The attack uniquely determines the 128-bit key of the cipher using less than 7 fault injections averagely. In the case with 4 fault injections, the attack limits the key to a space of size less than $2^{18}$ statistically.

22:17 [Pub][ePrint] New Cube Root Algorithm Based on Third Order Linear Recurrence Relation in Finite Field, by Gook Hwa Cho and Namhun Koo and Eunhye Ha and Soonhak Kwon

  In this paper, we present a new cube root algorithm in finite

field $\\mathbb{F}_{q}$ with $q$ a power of prime, which extends

the Cipolla-Lehmer type algorithms \\cite{Cip,Leh}. Our cube root

method is inspired by the work of M\\\"{u}ller \\cite{Muller} on

quadratic case. For given cubic residue $c \\in \\mathbb{F}_{q}$

with $q \\equiv 1 \\pmod{9}$, we show that there is an irreducible

polynomial $f(x)=x^{3}-ax^{2}+bx-1$ with root $\\alpha \\in

\\mathbb{F}_{q^{3}}$ such that $Tr(\\alpha^{\\frac{q^{2}+q-2}{9}})$

is a cube root of $c$. Consequently we find an efficient cube root

algorithm based on third order linear recurrence sequence arising

from $f(x)$. Complexity estimation shows that our algorithm is

better than previously proposed Cipolla-Lehmer type algorithms.

22:17 [Pub][ePrint] The IITM Model: a Simple and Expressive Model for Universal Composability, by Ralf Kuesters and Max Tuengerthal

  The universal composability paradigm allows for the modular design and analysis of cryptographic protocols. It has been widely and successfully used in cryptography. However, devising a coherent yet simple and expressive model for universal composability is, as the history of such models shows, highly non-trivial. For example, several partly severe problems have been pointed out in the literature for the UC model.

In this work, we propose a coherent model for universal composability, called the IITM model (``Inexhaustible Interactive Turing Machine\'\'). A main feature of the model is that it is stated without a priori fixing irrelevant details, such as a specific way of addressing of machines by session and party identifiers, a specific modeling of corruption, or a specific protocol hierarchy. In addition, we employ a very general notion of runtime. All reasonable protocols and ideal functionalities should be expressible based on this notion in a direct and natural way, and without tweaks, such as (artificial) padding of messages or (artificially) adding extra messages.

Not least because of these features, the model is simple and expressive. Also the general results that we prove, such as composition theorems, hold independently of how such details are fixed for concrete applications.

Being inspired by other models for universal composability, in particular the UC model and because of the flexibility and expressivity of the IITM model, conceptually, results formulated in these models directly carry over to the IITM model.

22:17 [Pub][ePrint] RSA private key reconstruction from random bits using SAT solvers, by Constantinos Patsakis

  SAT solvers are being used more and more in Cryptanalysis, with mixed results regarding their efficiency, depending on the structure of the algorithm they are applied. However, when it comes to integer factorization, or more specially the RSA problem, SAT solvers prove to be at least inefficient. The running times are too long to be compared with any well known integer factorization algorithm, even when it comes to small RSA moduli numbers.

The recent work on cold boot attacks has sparkled again the interest on partial key exposure attacks and in RSA key reconstruction. In our work, contrary to the lattice-based approach that most of these

works use, we use SAT solvers. For the special case where the public exponent $e$ is equal to three, we provide a more efficient modeling of RSA as an instance of a satisfiability problem, and manage to reconstruct the private key, given a part of the key, even for public keys of 1024 bits in few seconds.

22:17 [Pub][ePrint] Anonymity Guarantees of the UMTS/LTE Authentication and Connection Protocol, by Ming-Feng Lee and Nigel P. Smart and Bogdan Warinschi and Gaven Watson

  The UMTS/LTE protocol for mobile phone networks has been designed to offer a limited form of anonymity for mobile phone uses. In this paper we quantify precisely what this limited form of anonymity actually provides via a formal security model. The model considers an execution where the home and roaming network providers are considered as one entity. We consider two forms of anonymity, one where the mobile stations under attacked are statically selected before the execution, and a second one where the adversary selects these stations adaptively. We prove that the UMTS/LTE protocol meets both of these security definitions. Our analysis requires new assumptions on the underlying keyed functions for UMTS, which whilst probably true have not previously been brought to the fore.

22:17 [Pub][ePrint] More on linear hulls of PRESENT-like ciphers and a cryptanalysis of full-round EPCBC-96, by Stanislav Bulygin

  In this paper we investigate the linear hull effect in the light-weight block cipher EPCBC. We give an efficient method of computing linear hulls with high capacity. We then apply found hulls to derive attacks on the full 32 rounds of EPCBC--96 and 20 rounds of EPCBC-48. Using the developed methods we revise the work of J.Y. Cho from 2010 and obtain an attack based on multidimensional linear approximations on 26 rounds of PRESENT--128. The results show that designers of block ciphers should take seriously the threat coming from the linear hull attacks and not just limit themselves to proving bounds based solely on linear characteristics.

22:17 [Pub][ePrint] A Differential Fault Attack on MICKEY 2.0, by Subhadeep Banik and Subhamoy Maitra

  In this paper we present a differential fault attack on the stream cipher MICKEY 2.0 which is in eStream\'s hardware portfolio. While fault attacks have already been reported against the other two eStream hardware candidates Trivium and Grain, no such analysis is known for MICKEY. Using the standard assumptions for fault attacks, we show that by injecting around $2^{16.7}$ faults and performing $2^{32.5}$ computations on an average, it is possible to recover the entire internal state of MICKEY at the beginning of the key-stream generation


22:17 [Pub][ePrint] On the security of an identity-based authenticated group key agreement protocol for imbalanced mobile networks, by Haiyan Sun

  Recently, Islam and Biswas proposed a pairing-free identity-based authenticated group key agreement protocol for imbalanced mobile networks. However, in this letter, we point out that this protocol cannot resist passive attack, and cannot provide forward secrecy for joining operation and backward secrecy for leaving operation.

09:19 [Event][New] Summer School: Design and Security of Cryptographic Functions, Algorithms and Devices

  From July 30 to July 5
Location: Albena, Bulgaria
More Information:

09:18 [Event][New] Summer School on Design and Security of Cryptographic Functions, Algorithms and

  From July 30 to July 5
Location: Albena, Bulgaria
More Information:

05:54 [Job][New] Associate or Assistant Professor in Cryptology , Technical University of Denmark

  DTU Compute at the Technical University of Denmark calls for applications for a position as associate or assistant professor.

The department is looking for a dynamic faculty member to participate in research and teaching in cryptology.

The position is available from 1 May 2013.

For further information and to apply please follow the guidelines from the job page.