Abstract: A file having a data structure is provided which includes copied information, a first hash value, and a second hash value. The file can be generated by copying original information from an information source, performing a first hash operation on the copied information to generate the first hash value, and performing a second hash operation on the copied information and the first hash value to generate the second hash value. The first hash value proves integrity of the copied information with respect to the original information, and the second hash value proves integrity of the first hash value. Because the second hash value is based on a cryptographic hash of the first hash value and the copied information, the second hash value simultaneously allows authenticity of copied information and the first hash value to be confirmed. If either the copied information or the first hash value is changed, the second hash value will no longer match the first hash value.