In a cellular interception system, an information processing method for converting information of several cellular-network wireless messages from a first encrypted format under a session key, where each message is encrypted by a cellular ciphering algorithm chosen out of a collection of one or more cellular ciphering algorithms under the session key, to a second unencrypted format comprising: (A) divide the messages in the first format into two sets; the first set containing messages encrypted under the same encryption algorithm, and a second set containing the remaining messages. (B) subject the messages in the first set to a ciphertext-only cryptanalysis of a cellular encryption algorithm to recover the session key. (C) for each message in the second set, subject the message together with the recovered session key to the corresponding cellular ciphering algorithm to receive the message's information in the second format.