Patent ID: 8190903

Claim:
A method for verifying the authenticity of digital data comprising: extracting reproduction avoidance key information and log information for captured data from stored information if verification for the captured data is requested, wherein the reproduction avoidance key information comprises a time and space (TS) stamp at data capturing time, and is calculated using one way keyed hash function; calculating reproduction avoidance key information using the extracted log information, wherein the reproduction avoidance key information is a keyed hash message authentication code (HMAC) including the TS stamp; comparing the extracted reproduction avoidance key information with the calculated reproduction avoidance key information; and determining that the captured data has not been tampered, if the reproduction avoidance key informations are matched; wherein the keyed hash message authentication code (HMAC) is calculated by M =HMAC (Y II X II Z) and wherein the value M is a measurement value, the value Y is a previous measurement value, the value X is a secure hash algorithm (SHA1) of compressed data, the value Z is a current PCR value, and Y II X II Z is concatenation of Y, X and Z.