在线校验数字签名是否规范 （ETSI）
http://signatures-conformance-checker.etsi.org/pub/index.shtml
- XAdES (XML Advanced Electronic Signature ETSI 101 903, TS 103 171 and EN 319 132-1&2)
- CAdES (CMS Advanced Electronic Signature ETSI TS 101 733 and EN 319 122-1&2)
- ASiC (Associated Signature Container ETSI TS 102 918 and EN 319 162-1&2)
- PAdES (PDF Advanced Electronic Signature ETSI TS 102 778 and EN 319 142-1&2)