RFC 文档RFC 5280 - Internet X.509 Public Key Infrastructure Certificate and Certificate Revocation List (CRL) Profile附录 B. ASN.1 注释本页总览附录 B. ASN.1 注释 (ASN.1 Notes) 本附录包含对本规范中使用的 ASN.1 notation (ASN.1 表示法) 中一些较不常见特性的说明. 关键主题 (Key Topics) ASN.1 tagging conventions (标记约定) IMPLICIT 与 EXPLICIT tagging OPTIONAL 和 DEFAULT keywords ASN.1 encoding rules (编码规则, DER)