Patent ID: 7340607

Claim:
A method for preserving a document data file provided by a customer to a vendor of data preservation services, wherein a digital signature is coupled to said document data file, the method comprising: (a) forming a secure preservation request by: (a1) encoding said digital signature, together with an identification mark from said customer, using said vendor's public key, to form a preservation signature; (a2) coupling said document data file with said preservation signature to form said secure preservation request; (b) transferring said secure preservation request to said vendor; (c) decoding said preservation signature using said vendor's private key to obtain said digital signature and said identification mark; (d) decoding said digital signature, using said customer's public key to obtain a first unique data verifier; (e) processing said document data file to obtain a second unique data verifier; (f) comparing said first and second unique data verifiers; and (g) recording the data encoding of said document data file and said identification mark onto an analog medium in human-readable form.