A method to distribute and authenticate public encryption keys. A client concatenates its ID, its public key, and a secret password known to the client and a server, and hashes the result. The client forms an extended concatenation including the ID, the public key, and the hashed value, and sends the extended concatenation to the server. The server reads the ID and public key, and re-computes the hashed value based on its own knowledge of the password. If the received and the computed hashed values are the same, the server concludes that the client's public key is authentic. An analogous process enables the server to distribute its public key, and enables the client to authenticate the server's distributed public key.