A5/0

From CryptoDox, The Online Encyclopedia on Cryptography and Information Security

The encryption algorithm used in the GSM system is a stream cipher known as the A5 algorithm.

Multiple versions of the A5 algorithm exist which implement various levels of encryption^[1]:

• A5/0 utilizes no encryption.
• A5/1 is the original A5 algorithm used in Europe.
• A5/2 is a weaker encryption algorithm created for export and used in the United States.
• A5/3 is a strong encryption algorithm created as part of the 3rd Generation Partnership Project (3GPP).

The A5 algorithm is implemented in the Mobile Station (MS).

External Links

• Security of GSM System
• GSM Security & Encryption, David Margrave, George Mason University