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2013-11-26
08:03 [News] IACR Ethics Committee

 

The Ethics Committee of the IACR is responsible for providing recommendations to editors, program chairs, program-committee members, and reviewers concerning fairness and ethical aspects of all matters under the influence of the IACR, such as its operations, its events, and its publications.

The mission of the Ethics Committee is described in the "IACR Policy for the Ethics Committee", available at http://www.iacr.org/docs/

The Ethics committee has discussed only a handful of cases in 2013. In the interest of raising awareness for ethical matters among the researchers in cryptology, the Ethics Committee may occasionally inform the IACR members about its work. An account of one case follows.

A team of authors submitted a paper to a non-IACR conference in the field of cryptology and information security. After submitting the work, the authors developed their method further and discovered other ways to attack the problem. Before receiving an acceptance or rejection notification from the conference, the authors had written another paper on the second method and submitted this to a second conference, this one sponsored by the IACR. The second paper did not cite or mention the first paper.

Some reviewers in the overlap of the two program committees spotted a similarity of the works, and, in line with the IACR Policy on Irregular Submissions, they shared this information with the program chairs of the two venues. The program chair of the first conference then rejected the first paper declaring that it was a "potential double submission" and informed the program chair of the IACR conference about this. The authors then reached out to the IACR Ethics Committee and explained their case. They wanted to obtain a clarification that there was no double submission.

The Ethics Committee reviewed the situation and examined the submitted papers superficially. The committee then concluded that there was no obvious case of "parallel submissions" as described in the IACR Policy and that the second paper should enter the regular reviewing process of the IACR conference. The committee also remarked that it cannot make any statement towards the first conference because it is not an IACR venue. To the committee, it seemed that there was a misunderstanding because the existence and nature of technical links between the contributions of the two papers were not mentioned by the authors.

Last but not least, the committee recommended to the authors that, in the interest of being transparent in scientific work, authors should always cite existing known related work, even when a new contribution would not directly build on it. Furthermore, considering the delicate issues around double submissions, this point was particularly important with related work from the same authors.

IACR Ethics Committee (2013)

  • Josh Benaloh
  • Thomas Berson
  • Christian Cachin (chair)



07:58 [Event][New] SCN 2014: Ninth Conference on Security and Cryptography for Networks

  Submission: 14 April 2014
Notification: 9 June 2014
From September 3 to September 5
Location: Amalfi, Italy
More Information: http://scn.dia.unisa.it/




2013-11-25
22:17 [Pub][ePrint] Misuse Resistant Parallel Authenticated Encryptions, by Mridul Nandi and Nilanjan Datta

  The authenticated encryptions which resist misuse of initial value (or nonce) at some desired level of privacy are two-pass or Mac-then-Encrypt constructions (inherently inefficient but provide full privacy) and online constructions, e.g., McOE, sponge-type authenticated encryptions (such as duplex, AEGIS) and COPA. Only the last one is almost parallelizable with some bottleneck in processing associated data. In this paper, {\\em we design a new online secure authenticated encryption, called \\tx{ELmE} or Encrypt-Linear mix-Encrypt, which is completely (two-stage) {\\bf parallel} (even in associated data) and {\\bf pipeline implementable}}. It also provides full privacy when associated data (which includes initial value) is not repeated. The basic idea of our construction and COPA are based on \\tx{EME}, an Encrypt-Mix-Encrypt type SPRP constructions (secure against chosen plaintext and ciphertext). Unlike \\tx{EME}, we consider (so does COPA) online computable {\\bf linear mixing}. In addition with getting rid of bottleneck, our construction optionally supports {\\bf intermediate tags} which can be verified faster with less buffer size. Intermediate tag provides security against block-wise adversaries which is meaningful in low-end device implementation.



22:17 [Pub][ePrint] VMPC-R Cryptographically Secure Pseudo-Random Number Generator Alternative to RC4, by Bartosz Zoltak

  We present a new Cryptographically Secure Pseudo-Random Number Generator. It uses permutations as its internal state, similarly to the RC4 stream cipher. We describe a statistical test which revealed non-random patterns in a sample of $2^{16.6}$ outputs of a 3-bit RC4.

Our new algorithm produced $2^{46.8}$ undistinguishable from random 3-bit outputs in the same test. We probed $2^{51}$ outputs of the algorithm in different statistical tests with different word sizes

and found no way of distinguishing the keystream from a random source. The size of the algorithm\'s internal state is $2^{3424}$ (for an 8-bit implementation). The algorithm is cryptographically secure to the extent we were able to analyse it. Its design is simple and easy to implement. We present the generator along with a key scheduling algorithm processing both keys and initialization vectors.



22:17 [Pub][ePrint] Broadcast Amplification, by Martin Hirt and Ueli Maurer and Pavel Raykov

  A $d$-broadcast primitive is a communication primitive that allows a

sender to send a value from a domain of size $d$ to a set of parties.

A broadcast protocol emulates the $d$-broadcast primitive using only

point-to-point channels, even if some of the parties cheat, in

the sense that all correct recipients agree on the same value $v$

(consistency), and if the sender is correct, then $v$ is the value

sent by the sender (validity). A celebrated result by Pease, Shostak

and Lamport states that such a broadcast protocol exists if and only if $t 3$ no broadcast amplification

is possible, i.e., $\\phi_n(d)=d$ for any $d$.

However, if other parties than the sender can also broadcast some

short messages, then broadcast amplification is possible for

\\emph{any}~$n$. Let $\\phi^*_n(d)$ denote the minimal $d\'$ such that

$d$-broadcast can be constructed from primitives $d\'_1$-broadcast,

\\ldots, $d\'_k$-broadcast, where $d\'=\\prod_i d\'_i$ (i.e., $\\log

d\'=\\sum_i \\log d\'_i$). Note that $\\phi^*_n(d)\\leq\\phi_n(d)$.

We show that broadcasting $8n\\log n$ bits in

total suffices, independently of $d$, and that at least $n-2$ parties,

including the sender, must broadcast at least one bit. Hence

$\\min(\\log d,n-2) \\leq \\log \\phi^*_n(d) \\leq 8n\\log n$.



22:17 [Pub][ePrint] Efficient Template Attacks, by Omar Choudary and Markus G. Kuhn

  Template attacks remain a powerful side-channel technique to

eavesdrop on tamper-resistant hardware. They model the probability

distribution of leaking signals and noise to guide a

search for secret data values. In practice, several numerical

obstacles can arise when implementing such attacks

with multivariate normal distributions.

We propose

efficient methods to avoid these. We also demonstrate how to achieve

significant performance improvements, both in terms of information

extracted and computational cost, by pooling covariance estimates

across all data values. We provide a detailed and systematic

overview of many different options for implementing such

attacks. Our experimental evaluation of all these methods based on

measuring the supply current of a byte-load instruction executed in

an unprotected 8-bit microcontroller leads to practical guidance for

choosing an attack algorithm.



22:17 [Pub][ePrint] TOT, a Fast Multivariate Public Key Cryptosystem with Basic Secure Trapdoor, by Wuqiang Shen and Shaohua Tang

  In this paper, we design a novel one-way trapdoor function, and then propose a new multivariate public key cryptosystem called $\\rm TOT$, which can be used for encryption, signature and authentication. Through analysis, we declare that $\\rm TOT$ is secure, because it can resist current known algebraic attacks if its parameters are properly chosen. Some practical implementations for $\\rm TOT$ are also given, and whose security level is at least $2^{90}$. The comparison shows that $\\rm TOT$ is more secure than $\\rm HFE$, $\\rm HFEv$ and $\\rm Quartz$ (when $n \\ge 81$ and $D_{HFE} \\ge 129$, $\\rm HFE$ is still secure), and it can reach almost the same speed of computing the secret map by $\\rm C^\\ast$ and $\\rm Sflash^{v2}$ (even though $\\rm C^\\ast$ was broken, its high speed has been affirmed).



22:17 [Pub][ePrint] Beyond Modes: Building a Secure Record Protocol from a Cryptographic Sponge Permutation, by Markku-Juhani O. Saarinen

  BLINKER is a light-weight cryptographic suite and record protocol built from a single permutation. Its design is based on the Sponge construction used by the SHA-3 algorithm KECCAK. We examine the SpongeWrap authenticated encryption mode and expand its padding mechanism to offer explicit domain separation and enhanced security for our specific requirements: shared secret half-duplex keying, encryption, and a MAC-and-continue mode. We motivate these enhancements by showing that unlike legacy protocols, the resulting record protocol is secure against a two-channel synchronization attack while also having a significantly smaller implementation footprint. The design facilitates security proofs directly from a single cryptographic primitive (a single security assumption) rather than via idealization of multitude of algorithms, paddings and modes of operation. The protocol is also uniquely suitable for an autonomous or semi-autonomous hardware implementation of protocols where the secrets never leave the module, making it attractive for smart card and HSM designs.



22:17 [Pub][ePrint] CBEAM: Efficient Authenticated Encryption from Feebly One-Way $\\phi$ Functions, by Markku-Juhani O. Saarinen

  We show how efficient and secure cryptographic mixing functions can be constructed from low-degree rotation-invariant $\\phi$ functions rather than conventional S-Boxes. These novel functions have surprising properties; many exhibit inherent feeble (Boolean circuit) one-wayness and offer speed/area tradeoffs unobtainable with traditional constructs. Recent theoretical results indicate that even if the inverse is not explicitly computed in an implementation, its degree plays a fundamental role to the security of the iterated composition. To illustrate these properties, we present CBEAM, a Cryptographic Sponge Permutation based on a single $5 \\times 1$-bit Boolean function. This simple nonlinear function is used to construct a 16-bit rotation-invariant$\\phi$ function of Degree 4 (but with a very complex Degree 11 inverse), which in turn is expanded into an efficient 256-bit mixing function. In addition to flexible tradeoffs in hardware we show that efficient implementation strategies exist for software platforms ranging from low-end microcontrollers to the very latest x86-64 AVX2 instruction set. A rotational bit-sliced software implementation offers not only comparable speeds to AES but also increased security against cache side channel attacks. Our construction supports Sponge-based Authenticated Encryption, Hashing, and PRF/PRNG modes and is highly useful as a compact ``all-in-one\'\' primitive for pervasive security.



22:17 [Pub][ePrint] Multi-Input Functional Encryption, by S. Dov Gordon and Jonathan Katz and Feng-Hao Liu and Elaine Shi and Hong-Sheng Zhou

  \\emph{Functional encryption} (FE) is a powerful primitive enabling fine-grained access to encrypted data. In an FE scheme, secret keys (``tokens\'\') correspond to functions; a user in possession of a

ciphertext $\\ct = \\enc(x)$ and a token $\\tkf$ for the function~$f$

can compute $f(x)$ but learn nothing else about~$x$. An active area of research over the past few years has focused on the development of ever more expressive FE schemes.

In this work we introduce the notion of \\emph{multi-input} functional encryption. Here, informally, a user in possession of a token $\\tkf$ for an $n$-ary function $f$ and \\emph{multiple} ciphertexts $\\ct_1=\\enc(x_1)$, \\ldots, $\\ct_n=\\enc(x_n)$ can compute $f(x_1, \\ldots, x_n)$ but nothing else about the~$\\{x_i\\}$.

Besides introducing the notion, we explore the feasibility of multi-input FE in the public-key and symmetric-key settings, with respect to both indistinguishability-based and simulation-based definitions of security.



22:17 [Pub][ePrint] Differential Cryptanalysis and Linear Distinguisher of Full-Round Zorro, by Yanfeng Wang, Wenling Wu, Zhiyuan Guo and Xiaoli Yu

  Zorro is an AES-like lightweight block cipher proposed in CHES 2013, which only uses 4 S-boxes per round. The designers showed the resistance of the cipher against various attacks and concluded the cipher has a large security margin. Recently, Guo et. al have given a key recovery attack on full-round Zorro by using the internal differential characteristics. However, the attack only works for $2^{64}$ out of $2^{128}$ keys. In this paper, the secret key selected randomly from the whole key space can be recovered with a time complexity of $2^{108}$ full-round Zorro encryptions and a data complexity of $2^{112.4}$ chosen plaintexts. We first observe that the fourth power of the MDS matrix used in Zorro equals to the identity matrix. Moveover, several iterated differential characteristics and iterated linear trails are found due to the interesting property. We select three characteristics with the largest probability to give a key recovery attack on Zorro and a linear trail with the largest correlation to show a a linear distinguishing attack with $2^{105.3}$ known plaintexts. The results show that the security of Zorro against linear and differential cryptanalysis evaluated by designers is insufficient and the block cipher Zorro is far from a random permutation.