| abstract |
This invention generally relates to secure communications links for data transmission and more particularly relates to data communications links in which asymmetric cryptographic techniques are used to establish a secure link using symmetric cryptography. A method of establishing a secure communications link between a terminal and a server, the method comprising, assembling a message comprising a secret number and a digital signature for the secret number, the digital signature being generated using a private key for the server, encrypting the message at the server end of the communications link using a public key for the terminal, sending said encrypted message from the server to the terminal, decrypting said encrypted message at the terminal using a private key for the terminal, validating the message by checking the digital signature using a public key for the server; and establishing said secure communications link using said secret number, wherein the public and private keys for the terminal and server are public and private keys of an asymmetric cryptographic technique. Corresponding software is also provided. The method facilitates fast and if desired, anonymous, download of software to a mobile communications system terminal. |