Cryptanalysis Method and System

摘要

A cryptanalysis method comprising:
(A) Performing a ciphertext-only direct cryptanalysis of A5/1 and(B) Using results of Step (A) to facilitate the decryption and/or encryption of further communications that are consistent with encryption using the session key and/or decryption using the session key, wherein the cryptanalysis considers part of the bits of the session key to have a known fixed value, and wherein the cryptanalysis finds the session key. An efficient known plaintext attack on AS/2 comprises trying all the possible values for R4, and for each such value solving the linearized system of equations that describe the output;The solution of the equations gives the internal state of R1, R2, and R3;Together with R4, this gives the full internal state which gives a suggestion for the key.

主权项

1. A method for attacking encrypted GSM communications, said method comprising:
using a first wireless transceiver to impersonate a GSM cellular network before a wireless client device; using the first wireless transceiver to receive, from the wireless client device, an encrypted first GSM communication, which first GSM communication is intended for the GSM cellular network; using first processing circuitry to recover an encryption key used by the wireless client device to encrypt the first GSM communication; using a second wireless transceiver to impersonate the wireless client device before the GSM cellular network, using the recovered encryption key;