International Association for Cryptologic Research

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04:17 [Pub][ePrint] A Revocable Online-Offline Certificateless Signature Scheme without Pairing, by Karthik Abinav and Saikrishna Badrinarayanan and C. Pandu Rangan and S. Sharmila Deva Selvi and S. Sree Vivek and Vivek

  Certificateless Public key Cryptography is a widely studied paradigm due to its advantages of not

having the key-escrow problem and the lack of use of certificates. Online-Offline signature schemes are

extremely relevant today because of their great practical applications. In an online-offline signature

scheme all the heavy computation is done on powerful processors and stored securely in the offline

phase, and the online component requires only light computation. Hence, it is widely used in several

low-resource devices like mobile phones, etc. Revocation is another important problem of wide interest

as it helps to keep a check on misbehaving users. Currently, there are very few revocable certificateless

signature schemes in the literature. We have addressed some of the limitations of the previously existing

schemes and designed a new model for the same that involves periodic time generated keys. We present

a revocable online-offline certificateless signature scheme without pairing. Pairing, though a very useful

mathematical function, comes at the cost of heavy computation. Our scheme is proved secure in the

random oracle model using a tight security reduction to the computational Diffie-Hellman problem.


  In this paper, we propose a new signature scheme connecting two private keys and two public keys based on general non-commutative division semiring. The key idea of our technique engrosses three core steps. In the first step, we assemble polynomials on additive structure of non-commutative division semiring and take them as underlying work infrastructure. In the second step, we generate first set of private and public key pair using polynomial symmetrical decomposition problem. In the third step, we generate second set of private and public key pair using discrete logarithm. We use factorization theorem to generate the private key in discrete logarithm problem. By doing so, we can execute a new signature scheme on multiplicative structure of the semiring using multiple private keys. The security of the proposed signature scheme is based on the intractability of the Polynomial Symmetrical Decomposition Problem and discrete logarithm problem over the given non-commutative division semiring. Hence, this signature scheme is so much strong in security point of view.

01:17 [Pub][ePrint] An efficient FHE proposal based on the hardness of solving systems of nonlinear multivariate equations (II), by Gérald Gavin

  We propose a general framework to develop fully homomorphic encryption schemes (FHE) without using Gentry\'s technique. Initially, a private-key cryptosystem

is built over $\\mathbb{Z}_n$

($n$ being an RSA modulus). An encryption of $x\\in \\mathbb{Z}_n$

is a randomly chosen vector $e$ such that $\\Phi(e)=x$ where $\\Phi$ is a secret multivariate polynomial.

This private-key cryptosystem is not homomorphic in the sense that the vector sum is not a homomorphic operator. Non-linear homomorphic operators are then

developed. The security relies on the difficulty of solving systems of nonlinear equations (which is a $\\mathcal{NP}$-complete problem). While the security of our scheme has not been reduced to a provably hard instance of this problem,

its security is globally investigated.

10:45 [Event][New] CloudCom 2013: IEEE CloudCom 2013 (5th IEEE International Conference on Cloud Computing)

  Submission: 2 December 2013
From December 2 to December 5
Location: Bristol, United Kingdom
More Information:

19:17 [Pub][ePrint] On the Resilience and Uniqueness of CPA for Secure Broadcast, by Chris Litsas and Aris Pagourtzis and Giorgos Panagiotakos and Dimitris Sakavalas

  We consider the Secure Broadcast problem in incomplete networks. We study the resilience of the Certified Propagation Algorithm (CPA),

which is particularly suitable for ad hoc networks. We address the issue of determining the maximum number of corrupted players $t^{\\mathrm{CPA}}_{\\max}$ that CPA can tolerate under the $t$-locally bounded adversary model, in which the adversary may corrupt at most

$t$ players in each player\'s neighborhood. For any graph $G$ and dealer-node $D$ we provide upper and lower bounds on $t^{\\mathrm{CPA}}_{\\max}$ that can be efficiently computed in terms of a graph theoretic parameter that we introduce in this work. Along the way we obtain an efficient 2-approximation algorithm for $t^{\\mathrm{CPA}}_{\\max}$. We further introduce two more graph parameters, one of which matches $t^{\\mathrm{CPA}}_{\\max}$exactly. Our approach allows to provide an affirmative answer to the open problem of CPA Uniqueness posed by Pelc and Peleg in 2005.

12:18 [Job][New] Tenure-track Assistant/Associate Professor, University of Connecticut, USA


The Computer Science and Engineering (CSE) Department at the University of Connecticut invites applications for a tenure-track faculty position at the assistant or associate professor level, with an expected start date of August 23, 2014. The research specialties of interest are:

  1. Machine Learning,

  2. Privacy, Cryptography or Computer Security, or

  3. Techniques for the analysis of Big Data with applications in diverse areas including biomedical informatics.

The successful candidate will:

  • Develop and sustain an internationally-recognized, externally-funded research program in one of these areas of interest;

  • Teach undergraduate and graduate courses that meet the curricular needs of our CSE department;

  • Advise and mentor undergraduate and graduate students;

  • Provide service and leadership to all units of the University of Connecticut, to external academic and scientific communities, and to the general public.

Minimum Qualifications:

  1. Completed all requirements for a Ph.D. in computing or a related discipline by the time of the appointment—equivalent foreign degrees are acceptable;

  2. Research credentials in Computer Science, with a specialty in one of the topics prescribed above.

Preferred Qualifications:

  1. A record of consistent, outstanding research contributions in one of the topics prescribed above;

  2. Significant relevant teaching experience.

This is a 9-month, tenure-track position with an expected start date of August 23, 2014. The successful candidate`s primary academic

appointment will be at the Storrs campus with the option to work at UConn`s regional campuses across the state. Salary and rank will be

commensurate with qualifications.

To apply, applications must be submitted using Acade

07:17 [Pub][ePrint] SSS-V2: Secure Similarity Search, by Hyun-A Park

  Encrypting information has been regarded as one of the most substantial approaches to protect users\' sensitive information in radically changing internet technology era. In prior research, researchers have considered similarity search over encrypted documents infeasible, because the single-bit difference of a plaintext would result in an enormous bits difference in the corresponding ciphertext. However, we propose a novel idea of Security Similarity Search (SSS) over encrypted documents by applying character-wise encryption with approximate string matching to keyword index search systems. In order to do this, we define the security requirements of similarity search over encrypted data, propose two similarity search schemes, and formally prove the security of the schemes. The first scheme is more efficient, while the second scheme achieves perfect similarity search privacy. Surprisingly, the second scheme turns out to be faster than other keyword index search schemes with keywordwise encryption, while enjoying the same level of security. The schemes of SSS support \"like query(\'ab%\')\" and a query with misprints in that

the character-wise encryption preserves the degree of similarity between two plaintexts, and renders approximate string matching between the corresponding ciphertexts possible without decryption.

07:17 [Pub][ePrint] A Key Compromise Impersonation attack against Wang\'s Provably Secure Identity-based Key Agreement Protocol, by Maurizio Adriano Strangio

  In a 2005 IACR report, Wang published an efficient identity-based key agreement protocol (IDAK) suitable for resource constraint devices.

The author shows that the IDAK key agreement protocol is secure in the Bellare-Rogaway model with random oracles and also provides an ad-hoc security proof claiming that the IDAK protocol is not vulnerable to Key Compromise Impersonation attacks.

In this report, we claim that the IDAK protocol is vulnerable to key-compromise impersonation attacks. Indeed, Wang\'s results are valid only for a passive adversary that can corrupt parties or reveal certain session-specific data but is not allowed to manipulate protocol transcripts; a model considering this type of adversary is unable to afford KCI resilience.

07:17 [Pub][ePrint] Elliptic Curve Cryptography in Practice, by Joppe W. Bos and J. Alex Halderman and Nadia Heninger and Jonathan Moore and Michael Naehrig and Eric Wustrow

  In this paper, we perform a review of elliptic curve cryptography (ECC), as it is used in practice today, in order to reveal unique mistakes and vulnerabilities that arise in implementations of ECC. We study four popular protocols that make use of this type of public-key cryptography: Bitcoin, secure shell (SSH), transport layer security (TLS), and the Austrian e-ID card. We are pleased to observe that about 1 in 10 systems support ECC across the TLS and SSH protocols. However, we find that despite the high stakes of money, access and resources protected by ECC, implementations suffer from vulnerabilities similar to those that plague previous cryptographic systems.

07:17 [Pub][ePrint] Masking Tables---An Underestimated Security Risk, by Michael Tunstall and Carolyn Whitnall and Elisabeth Oswald

  The literature on side-channel analysis describes numerous masking schemes designed to protect block ciphers at the implementation level. Such masking schemes typically require the computation of masked tables prior to the execution of an encryption function. In this paper we revisit an attack which directly exploits this computation in such a way as to recover all or some of the masks used. We show that securely implementing masking schemes is only possible where one has access to a significant amount of random numbers.

07:17 [Pub][ePrint] TRS-80 With A Keccak Sponge Cake, by Jean-Marie Chauvet

  The subject of this paper, an improbable implementation of a recently standardized cryptographic hash function on a thirty-five-year-old microcomputer, may strike some as unusual and recreative at best. In the tedious discipline of the process, however, lessons were learned in implementation trade-offs for basic cryptographic primitives which may prove interesting in the current context of securing (small to nano) machine to machine communications. More importantly, that such insights might stem out of revisiting how earlier computing platforms relate to the code written on them to cast a distant light on modern connections of code to material, historical and contextual factors certainly illuminates the joys of retrocomputing.