| 摘要 |
A method (400) of generating a cryptographic checksum for a message M(x) is provided. The method is performed by a communication device, such as a sender or a receiver, and comprises calculating (405) the cryptographic checksum as a first function g of a division of a second function of M(x), f(M(x)), modulo a generator polynomial p(x) of degree n, g(f(M(x)) mod p(x)). The generator polynomial is calculated (403) as p(x) = (1 - x) ・P 1 (x), and P1(x) is a primitive polynomial of degree n— 1. The primitive polynomial is selected (402), based on a first cryptographic key, from the set of primitive polynomials of degree n— 1 over a Galois Field. By replacing a standard checksum with a cryptographic checksum, an efficient message authentication is provided. The proposed cryptographic checksum may be used for providing integrity assurance on the message, i.e., for detecting random and intentional message changes, with a known level of security. The proposed checksum is capable of detecting double-bit errors which may be introduced by a Turbo code decoder. |
