US Patent 7773495 Disc signature for disc authentication

The invention relates to a memory authentication method based on a pattern of storage areas of said memory that have altered latencies that are respectively altered such that the respective alteration of the latency of a storage area lies within a measurement noise of latency measurements in respect to the standard latency of said storage area when the measurement is performed with a reading device for accessing said record medium. The verification is then performed by a correlation of the latencies of the altered storage areas with a key used to alter the storage areas.