Surety’s patented Renewal process enables customers to create new Integrity Seals as hash algorithms become weak or compromised. MD5 and SHA-1 for example, have been shown by researchers to be vulnerable. Standards groups like NIST therefore recommend the use of newer, stronger algorithms.

The process of creating AbsoluteProof Seals involves using secure hash functions to create a unique digital fingerprint of protected data. These hash functions have a long, but limited lifetime. The AbsoluteProof Service is designed so that it can easily support newer, stronger secure hash functions as they are introduced.

When it is necessary to upgrade hash functions, customers can Renew their existing Seals using the new hash functions. This extends the life of the Seal beyond the life of the hash function that was used to create it while retaining the original sealing date and time. In effect, the old Seal is "refreshed" with the new secure hashng technology. A Renewal consists of a second Seal computed over the original document and the original Seal.

A renewed Seal will remain valid even after the original hash function becomes weak. In this process, the second Seal proves that the original Seal existed at a time before the original hash function was compromised. For this reason, it is important to renew before the original secure hash function is completely compromised.