1,881 research outputs found
On the Data Complexity of Statistical Attacks Against Block Ciphers (full version)
Many attacks on iterated block ciphers rely on statistical considerations using plaintext/ciphertext pairs to distinguish some part of the cipher from a random permutation. We provide here a simple formula for estimating the amount of plaintext/ciphertext pairs which is needed for such distinguishers and which applies to a lot of different scenarios (linear cryptanalysis, differential-linear cryptanalysis, differential/truncated differential/impossible differential cryptanalysis). The asymptotic data complexities of all these attacks are then derived. Moreover, we give an efficient algorithm for computing the data complexity accurately
Cryptanalysis of Block Ciphers Using Almost-Impossible Differentials
In this paper, inspired from the notion of impossible differentials, we present a model to use differentials that are less probable than a random permutation. We introduce such a distinguisher for 2 rounds of Crypton, and present an attack on 6 rounds of this predecessor AES candidate. As a special case of this idea, we embed parts of the additional rounds around the impossible differential into the distinguisher to make a probabilistic distinguisher with more rounds. We show that with this change, the data complexity is increased but the time complexity may be reduced or increased. Then we discuss that this change in the impossible differential cryptanalysis is commodious and rational when the data complexity is low and time complexity is marginal
Multidimensional Zero-Correlation Linear Cryptanalysis of the Block Cipher KASUMI
The block cipher KASUMI is widely used for security in many synchronous
wireless standards. It was proposed by ETSI SAGE for usage in 3GPP (3rd
Generation Partnership Project) ciphering algorthms in 2001. There are a great
deal of cryptanalytic results on KASUMI, however, its security evaluation
against the recent zero-correlation linear attacks is still lacking so far. In
this paper, we select some special input masks to refine the general 5-round
zero-correlation linear approximations combining with some observations on the
functions and then propose the 6-round zero-correlation linear attack on
KASUMI. Moreover, zero-correlation linear attacks on the last 7-round KASUMI
are also introduced under some weak keys conditions. These weak keys take
of the whole key space.
The new zero-correlation linear attack on the 6-round needs about
encryptions with known plaintexts. For the attack under weak keys
conditions on the last 7 round, the data complexity is about known
plaintexts and the time complexity encryptions
Impossible Differential Cryptanalysis of Pelican, MT-MAC-AES and PC-MAC-AES
In this paper, the impossible differential cryptanalysis is extended to MAC algorithms \textsc{Pelican}, MT-MAC and PC-MAC based on AES and 4-round AES. First, we collect message pairs that produce the inner near-collision with some specific differences by the birthday attack. Then the impossible differential attack on 4-round AES is implemented using a 3-round impossible differential property. For \textsc{Pelican}, our attack can recover the internal state, which is an equivalent subkey. For MT-MAC-AES, the attack turns out to be a subkey recovery attack directly. The data complexity of the two attacks is chosen messages, and the time complexity is about queries. For PC-MAC-AES, we can recover the 256-bit key with chosen messages and queries
Survey and Benchmark of Block Ciphers for Wireless Sensor Networks
Cryptographic algorithms play an important role in the security architecture of wireless sensor networks (WSNs). Choosing the most storage- and energy-efficient block cipher is essential, due to the facts that these networks are meant to operate without human intervention for a long period of time with little energy supply, and that available storage is scarce on these sensor nodes. However, to our knowledge, no systematic work has been done in this area so far.We construct an evaluation framework in which we first identify the candidates of block ciphers suitable for WSNs, based on existing literature and authoritative recommendations. For evaluating and assessing these candidates, we not only consider the security properties but also the storage- and energy-efficiency of the candidates. Finally, based on the evaluation results, we select the most suitable ciphers for WSNs, namely Skipjack, MISTY1, and Rijndael, depending on the combination of available memory and required security (energy efficiency being implicit). In terms of operation mode, we recommend Output Feedback Mode for pairwise links but Cipher Block Chaining for group communications
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