Document Integrity Verification System (DIVS™)

One of the strengths of eSigTek's electronic signing system is the Document Integrity Verification System (DIVS™). As each document is signed and accepted by the signing party, we create an Integrity Key™ by taking the file's "Digital Fingerprint". This Integrity Key is available to both the signing and issuing parties, allowing them to verify that a copy of the document in their posession is identical to the document created at the time of signing and stored on our servers.

To create this Integrity Key, we employ the industry-standard MD5 hashing algorithm. This algorithm applies a series of mathematical operations on the entirety of the PDF file to generate a 32-character hexedecimal key. The advantage of such a hashing system is that applying the same algorithm to altered files will not produce the same hash value, or Integrity Key, as the original file. Therefore, re-applying the algorithm to a file and comparing the resulting Integrity Key with the original Integrity Key generated when the document is signed and the PDF created allows anyone -- the signer, the document issuer, eSigTek, or any third party -- to verify the integrity of the signed document.