Zrtp

ZRTP

ZRTP is a cryptographic key-agreement protocol to negotiate the keys for encryption between two end points in a Voice over Internet Protocol (VoIP) phone telephony call based on the Real-time Transport Protocol. It uses Diffie-Hellman key exchange and the Secure Real-time Transport Protocol (SRTP) for encryption. ZRTP was developed by Phil Zimmermann, with help from Zooko Wilcox-O'Hearn and Colin Plumb and was submitted to the Internet Engineering Task Force (IETF) by Phil Zimmermann, Jon Callas and Alan Johnston on March 5, 2006 and published on April 11, 2011 as RFC 6189.