3.2. SRTP Cryptographic Contexts

3.2. SRTP Cryptographic Contexts

Each SRTP stream requires the sender and receiver to maintain cryptographic state information. This information is called the "cryptographic context".

SRTP uses two types of keys: session keys and master keys. By a "session key", we mean a key which is used directly in a cryptographic transform (e.g., encryption or message authentication), and by a "master key", we mean a random bit string (given by the key management protocol) from which session keys are derived in a cryptographically secure way. The master key(s) and other parameters in the cryptographic context are provided by key management mechanisms external to SRTP, see Section 8.