Identity and content authentication for phone calls

A method of authentication, comprising:

• performing an enrollment protocol between a client and a server to ensure that a user controls a phone number and to issue a certificate to the user;
• performing a handshake protocol between two calling parties including a caller and a callee through the server to authenticate the two calling parties;
• and
• performing a call integrity protocol to ensure security of a voice channel and a content it carries.

A method of authentication, comprising:

• performing an enrollment protocol between a client and a server to ensure that a user controls a phone number and to issue a certificate to the user;
• performing a handshake protocol between two calling parties including a caller and a callee through the server to authenticate the two calling parties;
• and
• performing a call integrity protocol to ensure security of a voice channel and a content it carries,
• wherein the enrollment protocol comprises:
• sending an enrollment request with the server's identity, the client's identity information, the client's phone number, and the client's public key by the client;
• sending a nonce NNet, the identities of the client and the server, and the phone numbers of the client and the server with a timestamp by the server;
• sending the nonce NNet and an audio nonce NAudio by the client;
• and
• replying with a signed certificate issued to the client by the server,
• wherein the handshake protocol comprises:
• indicating by the caller to the server that the caller want to place a call;
• informing by the server to the callee that an authenticated voice call is coming;
• and
• informing by the server to the caller whether the callee is using the authenticated voice call, and
• wherein the call integrity protocol comprises:
• sending a message indicating that a voice call is complete, and including a timestamp and a hash message authentication code (HMAC) of the timestamp by the caller and the callee;
• sending other audio digests by the caller and the callee after the voice call begins;
• and
• sending a call concluded message containing a timestamp with an HMAC.