Cryptanalysis of Alleged A5 Stream Cipher

Cryptanalysis of GSM encryption algorithm A5/1

The A5/1 algorithm is one of the most famous stream cipher algorithms used for over-the-air communication privacy in GSM. The purpose of this paper is to analyze several weaknesses of A5/1, including an improvement to an attack and investigation of the A5/1 state transition. Biham and Dunkelman proposed an attack on A5/1 with a time and data complexity of 239.91and 221.1, ...

Cryptanalysis of the A5/1 GSM Stream Cipher

Cryptanalysis of Stream Cipher Alpha1

Komninos, Honary and Darnell recently proposed stream cipher Alpha1. Alpha1 is based on A5/1 and is claimed to be much safer than A5/1. However Alpha1 is insecure: a 29-bit feedback shift register could be recovered with about 3000 known plaintext bits with O(2) operations. The rest of the message could be recovered in the broadcast application in which the same message is encrypted with differ...

Software-Hardware Trade-Offs: Application to A5/1 Cryptanalysis

This paper shows how a well-balanced trade-off between a generic workstation and dumb but fast reconfigurable hardware can lead to a more efficient implementation of a cryptanalysis than a full hardware or a full software implementation. A realistic cryptanalysis of the A5/1 GSM stream cipher is presented as an illustration of such trade-off. We mention that our cryptanalysis requires only a mi...

Two Trivial Attacks on A5/1:A GSM Stream Cipher

Stream ciphers play an important role in those applications where high throughput remains critical and resources are very restricted e.g. in Europe and North America, A5/1 is widely used stream cipher that ensure confidentiality of conversations in GSM mobile phones. However careful security analysis of such cipher is very important due to widespread practical applicability. The basic building ...