International Association for Cryptologic Research

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2012-10-16
15:17 [Pub][ePrint] Using Randomizers for Batch Verification of ECDSA Signatures, by Sabyasachi Karati and Abhijit Das and Dipanwita Roychowdhury

  Randomizers are popularly used to prevent various types of attacks on batch-verification schemes. Recently, several algorithms based upon symbolic computation are proposed for the batch verification of ECDSA signatures. In this article, we demonstrate that the concept of randomizers can be easily embedded in these symbolic-computation algorithms. The performance degradation caused by randomizers is comparable with that associated with ECDSA*.



15:17 [Pub][ePrint] New Constructions and Proof Methods for Large Universe Attribute-Based Encryption, by Yannis Rouselakis and Brent Waters

  We propose two large universe Attribute-Based Encryption constructions. In a large universe ABE construction any string can be used as an attribute and attributes need not be enumerated at system setup. Our first construction establishes a novel large universe Ciphertext-Policy ABE scheme on prime order bilinear groups, while the second achieves

a significant efficiency improvement over the large universe Key-Policy ABE systems of Lewko-Waters and Lewko. Both schemes are selectively secure in the standard model under two \"q-type\" assumptions similar to ones used in prior works. Our work brings back \"program and cancel\" techniques to this problem.

We provide implementations and benchmarks of our constructions

in Charm; a programming environment for rapid prototyping of cryptographic primitives.



15:17 [Pub][ePrint] Quantitative Analysis of the Full Bitcoin Transaction Graph, by Dorit Ron and Adi Shamir

  The Bitcoin scheme is a rare example of a large scale global

payment system in which all the transactions are publicly

accessible (but in an anonymous way). We downloaded the full history

of this scheme, and analyzed many statistical properties of its

associated transaction graph. In this paper we answer for the

first time a variety of interesting questions about the typical

behavior of account owners, how they acquire and how they spend

their Bitcoins, the balance of Bitcoins they keep in their

accounts, and how they move Bitcoins between their various

accounts in order to better protect their privacy. In addition, we

isolated all the large transactions in the system, and discovered

that almost all of them are closely related to a single large

transaction that took place in November 2010, even though the

associated users apparently tried to hide this fact with many

strange looking long chains and fork-merge structures in the

transaction graph.



15:17 [Pub][ePrint] ON PROVABLY SECURE CODE-BASED SIGNATURE AND SIGNCRYPTION SCHEME, by Preetha Mathew K and Sachin Vasant and C Pandu Rangan

  Signcryption is a cryptographic protocol that provides authentication and confidentiality as a single primitive at a cost lower than the combined cost of sign and encryption. Due to the improved efficiency, signcryption schemes have found significant applications in areas related to E-commerce. Shor\'s algorithm [22] poses a threat to number-theoretic algorithms, as it can solve the number-theoretic hard problems in polynomial time using quantum computers. Therefore, code-based cryptography offers an exciting alternative to number-theoretic cryptography, as it is not only resistant to quantum algorithms, but also, the base operation (matrix-vector multiplication) is far less computationally intensive

compared to the modular exponentiation required in number-theoretic schemes. Courtois, Finiasz and Sendrier proposed the only practical code-based signature(CFS signature) [7]. It can be used to realise

many cryptographic primitives. But the signature is currently not provably secure due to the existence

of the high rate distinguisher [11]. In this paper, we make use of an alternate key-construct for the CFS

signature, and thus prove its existential unforgeability under chosen message attacks (EUF-CMA). Also,

we propose a code-based signcryption scheme and proved its security. To the best of our knowledge,

this is the first code-based, provably secure signature and signcryption scheme in literature.



15:17 [Pub][ePrint] SHADE: Secure HAmming DistancE computation from oblivious transfer, by Julien Bringer and Herve Chabanne and Alain Patey

  We introduce two new schemes for securely computing Hamming distance in the two-party setting. Our first scheme is a very efficient protocol, based solely on 1-out-of-2 Oblivious Transfer, that achieves full security in the semi-honest setting and one-sided security in the malicious setting. Moreover we show that this protocol is significantly more efficient than the previous proposals, that are either based on garbled circuits or on homomorphic encryption. Our second scheme achieves full security against malicious adversaries and is based on Committed Oblivious Transfer. These protocols have direct applications to secure biometric identification.



05:35 [Event][New] ICEND 2013: 2nd International Conference on e-Technologies and Networks for Development

  Submission: 15 December 2012
Notification: 1 January 2013
From March 4 to March 6
Location: Kuala Lumpur, Malaysia
More Information: http://sdiwc.net/conferences/2013/Malaysia2/




2012-10-15
19:49 [Event][New] Africacrypt 2013

  Submission: 31 January 2013
Notification: 15 March 2013
From June 24 to June 26
Location: Cairo, Egypt
More Information: http://egyptscience.net/Africacrypt2013/index.html


02:41 [Event][New] NSS 2013: The 7th International Conference on Network and System Security (NSS 2013)

  Submission: 15 December 2012
Notification: 15 February 2013
From June 3 to June 4
Location: Madrid, Spain
More Information: http://anss.org.au/nss2013/index.htm


02:41 [Event][New] ICICS 2013: The 4th International Conference on Information and Communication Systems

  Submission: 1 December 2012
Notification: 20 January 2013
From April 23 to April 25
Location: Irbid, Jordan
More Information: http://www.icics.info/icics2013/




2012-10-14
15:17 [Pub][ePrint] Zero-Correlation Linear Cryptanalysis of Reduced-Round LBlock , by Hadi Soleimany

  Zero-correlation linear attack is a new method for cryptanalysis of block ciphers. In this paper we adapt Matrix method to find zero-correlation approximations. Then we present several zero-correlation linear approximations for 14 rounds of Lblock. Finally, we describe a cryptanalysis for 22 rounds of the reduced Lblock. While the previous attacks on Lblock used chosen plaintexts, the new attack needs distinct known plaintexts which is a more realistic model. Also the time complexity is $2^8$ times faster than the previous attack.



15:17 [Pub][ePrint] Improved side channel attack on the block cipher NOEKEON, by Changyong Peng and Chuangying zhu and Yuefei Zhu and Fei Kang

  NOEKEON is a block cipher having key-size 128 and block size 128,proposed by Daemen, J et al.Shekh Faisal

Abdul-Latip et al. give a side channel attack(under the single bit leakage model) on the cipher at ISPEC 2010.Their

analysis shows that one can recover the 128-bit key of the cipher, by considering a one-bit information leakage from

the internal state after the second round, with time complexity of O(2^68) evaluations of the cipher, and data complexity

of about 2^10 chosen plaintexts.Our side channel attack improves upon the previous work of Shekh Faisal Abdul-Latip

et al. from two aspects. First, we use the Hamming weight leakage model(Suppose the Hamming weight of the lower

64 bits and the higher 64 bits of the output of the first round can be obtained without error) which is a more relaxed

leakage assumption, supported by many previously known practical results on side channel attacks, compared to the

more challenging leakage assumption that the adversary has access to the \"exact\" value of the internal state bits as

used by Shekh Faisal Abdul-Latip et al. Second, our attack has also a reduced complexity compared to that of Shekh

Faisal Abdul-Latip et al. Namely, our attack of recovering the 128-bit key of NOEKEON has a time complexity 20.1

seconds on a PC with 2.6 GHZ CPU and 8G RAM and data complexity of 99 known plaintexts; whereas, that of

Shekh Faisal Abdul-Latip et al. has time complexity of O(2^68) and needs about 2^10 chosen plaintexts.