HTTP Content-Digest & Repr-Digest Builder

RFC 9530 is the modern replacement for the ambiguous Digest header of RFC 3230. It ships two distinct fields — Content-Digest covers the raw message body as sent (subject to Content-Encoding), and Repr-Digest covers the selected representation after decoding. This tool hashes any body you paste (or file you drop) with every algorithm listed in the RFC 9530 IANA registry and emits the exact structured-field value gateways and message-signature verifiers expect.

Body

Message body (bytes are hashed exactly as encoded — toggle raw / UTF-8 below)

Treat as UTF-8 text Treat as raw hex bytes Normalise CRLF → LF

Algorithms

Emit Repr-Digest instead of Content-Digest Include matching Want-* header with priorities

Parse & verify

Paste an existing Content-Digest or Repr-Digest value

The value is verified against the body above — each algorithm entry becomes a row with a match / mismatch verdict.

Cheat sheet

Content-Digest covers the octets on the wire — if the origin gzips the body, the digest is over the gzipped bytes. Recomputed by any intermediary that changes the encoding.
Repr-Digest covers the selected representation (after Content-Encoding is undone). Stable end-to-end — ideal input for HTTP Message Signatures (RFC 9421).
Want-Content-Digest / Want-Repr-Digest are the client-side hints. Each entry is a structured-field Item with a q-style integer priority from 0 to 10 — 0 disables the algorithm entirely.
Deprecated entries (md5, sha, adler, crc32c, unixsum, unixcksum) remain in the IANA registry but must not be used for integrity in new deployments — they exist only for backwards compatibility.