A system and method for authentication verifies the address of an information sender based on the sender's address, public key, and a digital signature. A portion of the sender's address is derived from the public key, such as by incorporating a portion of a hash of the public key with or without a modifier. The sender provides information including content data, the public key, the address, and the digital signature generated using the private key corresponding to the public key. Upon reception, the recipient verifies the address by recreating it from the public key. The signature is verified using the network address and public key. The recipient accepts the content data when both the address and signature are verified. The content data may include a communications parameter of the sender, such as a care-of address where the sender is a mobile device and the recipient is the sender's home agent.