Patent ID: 9634832
Date: 2017-04-25
CPC Classifications: H04L,H04W

Claim:
1. A method for processing an encrypted GSM digital communication, said method comprising: intercepting a wireless signal containing an encrypted first ciphertext; performing a ciphertext only cryptanalysis of the first ciphertext through the use of processing circuitry, wherein said cryptanalysis comprises deriving equations for bits of key-stream used to encrypt at least a portion of the first ciphertext, wherein said deriving includes either: (1) XORing together bits of the first ciphertext based on an error correction coding scheme, or (2) XORing bits of said first ciphertext with bits which are an output of an error correction coding scheme; or (3) both; and using resulting output of said cryptanalysis to decrypt or produce a second ciphertext wherein said first and second ciphertexts are consistent with encryption of a first and a second unencrypted GSM messages using an identical cryptographic key.