Showing papers on "Null cipher published in 2005"
Patent•
17 Feb 2005TL;DR: In this paper, a stream cipher encryption and message authentication scheme is described, in which a key stream at the transmitting end is generated from a state value, and the key stream is applied to plaintext to generate an encrypted message block having at least a portion of the plaintext converted to ciphertext.
Abstract: Stream cipher encryption and message authentication. Stream cipher encryption is performed by generating a keystream at the transmitting end from a state value, applying the keystream to plaintext to generate an encrypted message block having at least a portion of the plaintext converted to ciphertext, and updating the state value as a function of said at least a portion of the plaintext. Stream cipher decryption is performed by generating a keystream at the receiving end from the same state value, applying the keystream to the encrypted message block to convert the ciphertext to plaintext, and updating the state value as a function of the plaintext. Message authentication techniques are also described.
17 citations
Posted Content•
TL;DR: In this article, known-plaintext attacks on the HBB have been studied in both the classical B and asynchronous SS modes, where the plaintext of the cipher can be known only a small part of its plaintext.
Abstract: In this paper, we show several known-plaintext attacks on the stream cipher HBB which was proposed recently at INDOCRYPT 2003. The cipher can operate either as a classical stream cipher in the “B mode” or as an asynchronous stream cipher in the “SS mode”. In the case of the SS mode, we present known-plaintext attacks recovering 128-bit key with the complexity 2 and 256-bit key with the complexity 2. In the case of B mode with 256-bit key, we show a known-plaintext attack recovering the whole plaintext with the complexity 2. All attacks need only a small part of the plaintext to be known.
10 citations
9 May 2005
TL;DR: It is shown that when the cryptanalyst has access to an oracle under one mode, then almost all other related-cipher modes can be attacked with ease.
Abstract: In this paper, we present a generalization of the notion of the recently proposed related-cipher attacks. In particular, we show that when the cryptanalyst has access to an oracle under one mode, then almost all other related-cipher modes can be attacked with ease. Typically only one chosen plaintext/ciphertext query is required, while computational complexity is negligible.
8 citations