* 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.
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.