Patent ID: 7523111

Claim:
A method of enabling selection of one or more pieces of secret information stored in a first entity without revealing the one or more pieces of secret information, the one or more pieces of secret information being one or more secret keys for use with a corresponding encryption or decryption function, the first entity also storing an identity of each of the one or more secret keys which are each indicative of an access permission to the first entity associated with each of the one or more pieces of secret information, the method comprising the steps of: (a) a second entity selecting one or more pieces of secret information by requesting, from the first entity, one or more of the access permissions and the associated one or more of the key identities for the selected one or more of the pieces of secret information stored in the first entity together with said encryption or decryption function; and (b) in response to the selection request, the first entity outputting the access permissions and key identities to the second entity for use with said encryption or decryption function stored in the second entity without outputting the one or more pieces of secret information.