Abstract: A system, apparatus, method, and machine readable medium are described for performing authentication over multiple channels. For example, one embodiment of a method comprises: performing authentication over a network with an authentication service to authenticate a client; responsively generating a token at the authentication service, the token including identification information for the client, a service, and a type of authenticator used for the authentication, the token further including verification data; transmitting the token to the client; transmitting the token from the client to the service, the service using the verification data to verify the token and allowing one or more transactions with the client in accordance with a policy based, at least in part, on the type of authenticator used for the authentication.

Abstract: A computer readable medium includes executable instructions to insert partial authentication content into a message. The modified message is then delivered through an electronic network to a recipient. Upon receipt, the partial authentication content is processed without processing the entire message. This results in an authentication response indicative of the authenticity of the message. In some instances the message is partially authenticated and therefore delivered. In other instances, the message is not partially authenticated and various processing options are invoked, such as quarantining the message, modifying the message with a warning, modifying the message to remove content, and/or sending a message to a spoofed machine advising the spoofed machine of a spoofed message. The authentication operations of the invention may also be used in connection with the implicit content of the message.