Patent ID: 6983369
Filing Date: 2006-01-03
Classification: G06F,H04L

Abstract:
1. A method of authentication, comprising the steps of: a) sending first information from a contents-information receiver apparatus to a contents-information sender apparatus, the first information including a combination of certificate information representative of presence of a license granted to the contents-information receiver apparatus and identification information for identifying the contents-information receiver apparatus, the first information further including a signal of a signature for the combination of the certificate information and the identification information; b) in the contents-information sender apparatus, determining whether the combination of the certificate information and the identification information in the first information sent by the step a) is correct or wrong in response to the signal of the signature in the first information; c) in the contents-information sender apparatus, extracting the identification information from the first information sent by the step a) and storing the extracted identification information; d) sending the identification information from the contents-information receiver apparatus to the contents-information sender apparatus at a time different from a time of the step a); and e) in the contents-information sender apparatus, collating the identification information sent by the step d) with the identification information stored by the step c).