--- id: "x509_serial_number" kind: "datatype" status: "draft" is_pii: false categories: ["cryptography"] langs: ["common"] quality: 80 url: "https://registry.apicrafter.io/datatype/x509_serial_number" --- # X.509 certificate serial number (`x509_serial_number`) > **Draft.** Draft records have not been reviewed yet and may be incomplete or wrong; do not treat them as authoritative for legal or compliance decisions. Serial number that a certification authority assigns to a certificate, unique among the certificates it issues. RFC 5280 limits it to 20 octets. Certificate stores and registries print it in hexadecimal, with or without colons between octets; a leading 00 octet is the sign byte of the DER integer, so a 20-octet number may take 21 octets. The format alone looks like any hexadecimal string: the type is told by the field name (serial, serialNumber, СерийныйНомер). - Personal data (PII): no - Categories: Cryptographic identifiers (cryptography) - Countries: global - Languages: Common to most languages (common) - Classification: identifier ## Detection Regular expression (Python `re`): ``` ^(?:(?:[0-9A-Fa-f]{2}){1,21}|[0-9A-Fa-f]{2}(?::[0-9A-Fa-f]{2}){1,20})$ ``` ## Examples - `00A94CF4CA0000000005A1` — CA certificate of an accredited Russian certification authority (e-trust.gosuslugi.ru) - `3382BD430000000004B0` — Serial number in the style of Microsoft and CryptoPro CA - `00:a9:4c:f4:ca:00:00:00:00:05:a1` — The first number with colons, as openssl x509 -text prints it - `00A94CF4CA0000000005A100A94CF4CA0000000005A1` (invalid example) — 22 octets, longer than RFC 5280 allows ## Translations - ru: Серийный номер сертификата X.509: Номер, который удостоверяющий центр присваивает сертификату; уникален среди выданных им сертификатов. Записывается в шестнадцатеричном виде, до 20 октетов (RFC 5280). ## Sources - doc: ## Quality Score 80/100. Missing: mapping (Wikidata, Schema.org, ...), detector coverage. JSON: · Edit: