A system and method is presented for establishing a secure conduit for SMS communication between a center and a wireless terminal. The center encrypts an authorization key in response to a wireless terminal's SMS message containing a public key and a request for the authorization key, sends back to the wireless terminal an SMS message containing the encrypted authorization key, decrypts another SMS message received from the wireless terminal which contains an authentication code and a request for a traffic key, authenticates the SMS message, encrypts the traffic key, and sends to the wireless terminal another SMS message containing the traffic key.