Composite cryptographic keys

摘要

The present invention relates to the generation of a composite cryptographic key. In one example, we show how to specify an elliptic curve public key, an RSA public key and a DSA public key all in a single 2048 bit block. The method gives a wide choice of finite fields and curves for use in the ECC system and introduces no known security weaknesses. The method hence allows algorithm type to be decided at run time, rather than at the time the public keys are distributed. However, this is done without the need for very large key lengths.