Cellular Message Encryption Algorithm

The CMEA ( Cellular Message Encryption Algorithm ) is a block cipher which is used in American mobile systems and was developed by James A. Reed in 1991 at AT & T. It is patented in U.S. patent 5,159,634.

It is used to control the data in U.S. mobile networks at the radio transmission to encrypt and has a similar scope as the A5 algorithm used in Europe and GSM networks.

The algorithm is byte-oriented and can work with block sizes between two and six bytes. The key length is 64 bits. CMEA is considered unsafe.