| 摘要 |
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 mobile terminal of a mobile communications system and a server, the method comprising: retrieving from storage, in the mobile terminal a prime number, p, and generator, g, for a Diffie-Hillman key exchange protocol; generating a positive integer b at the terminal; sending a message including the value of (g<b>mod p) from the terminal to the server; determining a shared secret number for the terminal and the server by calculating the value of (g<ab >mod p), where a is a positive integer, at both the terminal and the server, using b and a public value for the server y=g<a >mod p at the terminal, and using a, b, g and p at the server; and using the shared secret number to establish said secure communications between the terminal and the server. Corresponding software is also provided. The method facilitates fast and if desired, anonymous, download of software to a mobile communications system terminal.
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