Validate electronic signatures by uploading a metadata file or by entering data for individual signatures. A valid signature means that the signature data has been signed with the accompanying certificate. Although a signature is verified valid, it may not be certain that it relates to a particular document. You can calculate the MD5 value for a file by selecting a file under MD5. Verify that the MD5 value in the signature data matches the calculated MD5 value for the file. You should also check who the certificate is issued to and that the signature was made with a valid certificate, check the date in the signature date and compare with the certificate from date and end date.