1. A computer-implemented method for producing a validation certificate, the method comprising: signing a document, at least one schema, and a validation report, wherein the validation report indicates a validation status of the document based on the at least one schema; the signing including: computing a digest value of the document, the at least one schema, and the validation report; and encrypting the digest value to produce a digital signature, the validation certificate comprising: the digital signature; at least one of the document and a solvable reference to the document; at least one of the at least one schema and a solvable reference to the at least one schema; and at least one of the validation report and a solvable reference to the validation report.