ZRTP (composed of Z and Real-time Transport Protocol) 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 Bryce Wilcox-O'Hearn, Colin Plumb, Jon Callas and Alan Johnston and was submitted to the Internet Engineering Task Force (IETF) by Zimmermann, Callas and Johnston on March 5, 2006 and published on April 11, 2011 as RFC 6189.
ZRTP ("Z" is a reference to its inventor, Zimmermann; "RTP" stands for Real-time Transport Protocol) is described in the Internet Draft as a "key agreement protocol which performs Diffie–Hellman key exchange during call setup in-band in the Real-time Transport Protocol (RTP) media stream which has been established using some other signaling protocol such as Session Initiation Protocol (SIP). This generates a shared secret which is then used to generate keys and salt for a Secure RTP (SRTP) session." One of ZRTP's features is that it does not rely on SIP signaling for the key management, or on any servers at all. It supports opportunistic encryption by auto-sensing if the other VoIP client supports ZRTP.
Everyway that I can
I feel you're moving on a different cause
Makin' a way for a distant course
You say you love me and you roll your eyes
Turn to stare at the empty skies
I thought it was over and we passed all that
All we've done is to pass back to frame number one
C'mon now now
I wanna show you all again what it would be like
Just let go and let me love you
Everyway that I can
I'll try to make you love me again
Everyway that I can
I'll give you all my love and then
Everyway that I can
I'll cry ; I'll die and make you mine again
Hold me closer oh so good
You make me feel just like I should
I know whatcha thinkin' uh-hu good
Now, the rest of the world is overruled
Tell me whatcha see in other girls all around
Come on closer and tell me whatcha don't find here
Come on now now
I wanna give you everything you've been missin' out
Just let go and let me love you
Everyway that I can
I'll try to make you love me again
Everyway that I can
I'll give you all my love and then
Everyway that I can
I'll cry ; I'll die and make you mine again
I'm in love with you
I'll do all you want me to
Make me wanna huh-huh
Make me wanna huh-huh
Nothing in the world
That could stop me no sir
No no no
Everyway that I can
I'll try to make you love me again
Everyway that I can
I'll give you all my love and then
Everyway that I can
I'll cry ; I'll die and make you mine again...