In this paper, we present a framework for guess-and-determine attack on stream ciphers that relies on guessing part of the internal state and solving for the remaining unknown cipher state based on known keystream bits. We show that this basic attack can always be extended to a Time-Memory-Data (TMD) Trade-Off attack. This allows us to easily extend any guess-and-determine attack to a guess-and...

We determine the imbalances of the keystreams produced by Achterbahn-80 and Achterbahn-128 in two different ways. The number of cyclically inequivalent keystreams produced by the keystream generators of Achterbahn-80 and Achterbahn-128 is determined. An abstract model for the keystream generator of a primitive NLFSR combination generator is used to justify the correlation attack introduced in [...

Stream Cipher is a cryptographic primitive that is used to make sure privacy on a communication channel. SNOW family is a typical example of word oriented stream ciphers based on Linear Feedback Shift Register (LFSR). In this paper two versions of SNOW family have been analyzed against Guess and Determine (GD) Attack. Original SNOW 2.0 is an improved version of SNOW 1.0 claimed to be more secur...

In this paper, we investigate the security of SNOW-V, demonstrating two guess-and-determine (GnD) attacks against full version with complexities 2384 and 2378, respectively, one distinguishing attack a reduced variant complexity 2303. Our GnD use enumeration recursion to explore valid guessing paths, try truncate as many invalid paths possible at early stages by carefully designing order guessi...

This note presents a very simple guess and determine attack on Snow requiring 9 key stream words and about 2 computations.

Khudra is a lightweight block cipher designed for Field Programmable Gate Array (FPGA) based platforms. The cipher has an 18-round generalized type-2 Feistel structure with 64-bit block size. The key schedule takes 80-bit master key and produces 32-bit round keys performing very simple operations. In this work, we analyze the security of Khudra. We first show that the effective round key length...

In Europe and North America, the most widely used stream cipher to ensure privacy and confidentiality of conversations in GSM mobile phones is the A5/1. In this paper, we present a new attack on the A5/1 stream cipher with an average time complexity of 2, which is much less than the brute-force attack with a complexity of 2. The attack has a 100% success rate and requires about 5.65GB storage. ...

In Europe and North America, the most widely used stream cipher to ensure privacy and confidentiality of conversations in GSM mobile phones is the A5/1. In this paper, we present an improved guess-and-determine attack on the A5/1 stream cipher with an average time complexity of 248.5, which is much less than any known guessand-determine attack. The attack has a 100% success rate and requires a ...

Remote authentication is a method to authenticate remote users over insecure communication channel. Password-based authentication schemes have been widely deployed to verify the legitimacy of remote users. Very recently, Hsiang et al. pointed out that Yoon et al’s scheme is vulnerable to parallel session attack, masquerading attack and password guess attack. They proposed an improved scheme to ...

SNOW 2.0 is a word oriented stream cipher that has been selected as a standard stream cipher on ISO/IEC 18033-4. One of the general attacks on the stream ciphers is Guess and Determine attack. Heuristic GD attack is GD attack that represents an algorithmic method to analysis the stream cipher with the variables of the same size. The results of HGD attack on TIPSY, SNOW 1.0 and SNOW 2.0 stream c...