Reference Explainer

Base64 Encoding

Base64 converts binary-safe data to ASCII text for transport.

What It Is

  • Base64 maps binary bytes into a fixed alphabet of 64 characters.
  • It is an encoding format, not encryption, so it provides no confidentiality.
  • Base64URL is a variant used by JWT with URL-safe characters.

Common Pitfalls

  • Treating Base64 as secure or secret.
  • Forgetting padding and URL-safe substitutions.
  • Incorrectly decoding UTF-8 payloads as Latin-1 text.