Веб-Стандарт и Спецификация RFC

Base64 и Base64URL — Технические Различия и Стандарты

Различия между стандартным Base64 и веб-безопасным Base64URL: замена символов, паддинг и стандарты JWT.

Почему стандартный Base64 не подходить для URL

Standard Base64 (RFC 4648 §4) uses the 64-character alphabet A-Z, a-z, 0-9, +, /, with = used as trailing byte padding.

However, when standard Base64 strings are passed in HTTP query parameters, URI path segments, or web cookies:

  • The plus sign + is automatically interpreted by web servers as a space character (%20), corrupting the payload.
  • The forward slash / is interpreted by web routers as a path delimiter, altering URL routing logic.
  • The equals sign = is used as a key-value parameter separator in query strings.

Замена символов алфавита (RFC 4648 §5)

FeatureStandard Base64Base64URL (URL-Safe)
Index 62+ (plus)- (hyphen)
Index 63/ (slash)_ (underscore)
Padding Character (=)Mandatory (Length % 4 == 0)Omitted or Unpadded

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