Patent ID: 7194633

Claim:
A data-processing system comprising a processor, a second encrypted cryptographic key stored in a first persistent memory, a cryptographic co-processor comprising a first register and a second register, for decrypting in a decryption step said second encrypted cryptographic key, thereby generating therefrom a second unencrypted cryptographic key that is usable by said processor for executing an operation, wherein for said decryption step said first register is loadable with said second encrypted cryptographic key and said second register is loadable with a first cryptographic key, and wherein said resulting second unencrypted cryptographic key is maintainable in one of said registers for being used by said cryptographic co-processor for one of decrypting encrypted information and encrypting unencrypted information for the operation, and wherein the resulting second unencrypted cryptographic key is maintainable in said first register and said co-processor is designed such that the content of either of the registers is usable by said cryptographic co-processor for one of decrypting and encrypting the content of the other of the registers.