[bjacobt]

You may want to look at https://guardtime.com/ for audit/data tampering concerns.

I'm copy pasting this from their site https://guardtime.com/ksi-technology

* A user interacts with the KSI system by submitting a hash-value of the data to be signed into the KSI infrastructure and is then returned a signature which provides cryptographic proof of the time of signature, integrity of the signed data, as well as attribution of origin i.e. which entity generated the signature.