Patent ID: 7971063
Filing Date: 2011-06-28
Classification: H04L

Abstract:
1. A method comprising: (i) inserting at least one digital signature image into an electronic document, (ii) generating a first check sum for the electronic document having the inserted digital signature image using a first hash function, (iii) generating a second check sum for the electronic document having the inserted digital signature image using a second hash function, (iv) generating a random value, (v) symmetrically-encrypting the first check sum using a key, wherein the key for the symmetric encryption is the sum of the second check sum and the generated random value, (vi) attaching the symmetrically-encrypted first check sum to the electronic document, (vii) asymmetrically-encrypting the generated random value with a first public key of a first key pair comprising a first private key and the first public key, and (viii) adding the asymmetrically-encrypted random value to the electronic document.