Verifying a proof of existence using the Woleet API is straightforward: the API takes care of verifying that the proof receipt is valid and correctly anchored in a Bitcoin transaction, so you just need to check that the SHA256 hash of the file matches the proof receipt’s hash property.
Verifying a proof of signature using the Woleet API is also straightforward: the API takes care of verifying that the proof receipt is valid and correctly anchored in a Bitcoin transaction, then verifies the signature, and optionally verifies that the signee owns the public key and the TLS certificate, so you just need to check that the SHA256 hash of the file matches the proof receipt’s signedHash property.
The Woleet API can also be used to verify any Chainpoint 1 or 2 proof receipt, including those created by other providers.
Woleet also provides an open source JavaScript library for web clients implementing the full verification process without the help of the Woleet API.