1. A method, implemented by a server computer system programmed to perform the following, comprising: generating, by the server computer system, a signature revocation list to indicate revocation status of a signature used by a signer to sign a document, the signature comprising a signing certificate issued by a trusted authority and the document that has been hashed by a hash function and encrypted by a private key of the signer of the document; computing, by the server computer system, an identifier of the signature in the signature revocation list based on contents of the signature; and publishing, by the server computer system, the signature revocation list for access by users of the document.