I see there a number of free TSA services according to this page (not all are still in service).
In other sources I see references to the requirement of audits for the TSA to be 'rfc3161 compliant'. Given the number of free services, not to mention the new blockchain services (which are similar but not exactly the same as rfc3161), I'm finding it difficult to imagine they have all spent money on getting audited and certified. (This may pose a problem if and when the timestamps are presented before a legal court and their validity addressed or refuted by the opposing party). I am curious to know for the U.S.:
- Are audits performed by a specific organization or private contractor?
- In the U.S., is there an organization responsible for issuing a 'seal of approval'?