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RFC 2045 / MECHANISM GUIDE

Canonical form and safety

05

Canonicalization, transfer encoding, and media interpretation are different processing stages.

Related RFCs and changes

“Updates” changes part of an earlier RFC. “Obsoletes” replaces it. This list shows selected related documents.

DIAGRAM§ 6.6 ↗
RFC 2045 · § 6.6EXAMPLE
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Canonical form and safetyCanonicalization, transfer encoding, and media interpretation are different processing stages.Canonical form and safetyMedia canonical formtransfer encodeTransport-safe body textdecode, then interpretRecovered media bytes
03
Recover before interpretation

Decode the transfer form, then interpret the media type safely.

Protocol participantThreat or exceptionProtocol controlSimplified drawings · precise section references
KEY POINT

Text canonical form uses CRLF line breaks as specified.

  • Text canonical form uses CRLF line breaks as specified.
  • A charset converts characters to bytes; transfer encoding converts bytes to transport-safe text.
  • Decoders still need safe media handling and appropriate resource limits.
DETAILS

Examples are illustrative. Consult the linked RFC and its errata for implementation details.

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Diagrams simplify the RFC. Read the linked sections for complete requirements.

Privacy
All chapters in this RFC
  1. MIME entity headers
  2. Content type and charset
  3. Quoted-printable bytes
  4. Base64 body encoding
  5. Canonical form and safety
RFC 9700 / CHAPTERS

Chapters

For full details, tables, algorithms, and exceptions, read the original RFC.

RFC status and corrections ↗