Patent ID: 6792534
Filing Date: 2004-09-14
Classification: H04L

Abstract:
A method for exchanging a symmetric media stream key between first and second call management servers, wherein a communication path between the first and second call management servers includes one or more intermediary transfer devices, the first and second call management servers exchanging a plurality of call signaling messages via the one or more intermediary transfer devices, wherein the one or more intermediary transfer devices are configured to handle and forward the plurality of call signaling messages, the method comprising:receiving, at the second call management server, a first portion of the symmetric media stream key to be used in a subsequent data transmission between the first and second call management servers, wherein the first portion of the symmetric media stream key is unprotected during its transmission from the first call management server to the second call management server via the one or more intermediary transfer devices; using a security mechanism to protect a second portion of the symmetric media stream key to be used in the subsequent data transmission; upon receiving the first portion of the symmetric media stream key, transferring the protected second portion of the symmetric media stream key from the second call management server to the first call management server via the one or more intermediary transfer devices; upon receiving the protected second portion of the symmetric media stream key at the first call management server, using the first portion and the protected second portion of the symmetric media stream key to secure communications between the first and second call management servers; wherein the one or more intermediary transfer devices are unable to decrypt the protected second portion of the symmetric media stream key.