1. A method comprising: receiving, from a sender having a claimed identity, a session invitation having a session address; authenticating the claimed identity, the authenticating comprising: receiving an audio signal from the sender corresponding to a text phrase; receiving a voice template corresponding to the claimed identity; comparing the audio signal to the voice template, to yield a confidence score; and when the confidence score exceeds a threshold, generating an authentication certificate; and upon generating the authentication certificate: generating a session identification; packaging the session identification with the authentication certificate, to yield authentication information; and transmitting the authentication information to the session address.