The Secure Real Time Transport Protocol (SRTP) is based on the Real Time Transport Protocol (RTP). SRTP denotes a technical process for the encrypted transfer of multimedia data (for example speech) via existing networks.
SRTP is used for example in internet telephony (Voice over IP, in short: VoIP), in order to guarantee an eavesdrop-secure transfer of telephone data between multiple conversation participants. The NFON voice encryption system utilises the Transport Layer Security Standard (TLS) and the SRTP Standard. This is not only secure but also efficient. The encryption in telephone systems varies and can be integrated into the hardware or realised with the requisite software.