Abstract: An authentication system and a method of creating a secure check value used by the system to verify the integrity and authenticity of data. The authentication system comprises one or more processors, data stores, and network interfaces that can communicate among themselves and with other devices. The secure check value is created by combining some or all of a cryptographic digest with the data to be secured and then outputting a secure check value by using a checksum or hash. The secure check value is associated with the data and can be used to verify the integrity and authenticity of the data after transferring the data and check value to a different location or at some point in the future.