WALLE

Five techniques · file by data

What each extractor can claim

Envelope, signature, packets, hash. The name is a label, not a shelf. Agreement is two techniques meeting on one pose. MAGPIE stays 19/658,750.

• Envelope

  Name, size, MIME, modified time — what the host already holds.

  Cannot prove contents. MIME is a suggestion.

• Signature

  Magic bytes at the head: JPEG, PNG, PDF, ZIP, ID3, ISO-BMFF.

  Cannot read titles, authors, or dates from the signature alone.

• Packets

  EXIF, XMP, PNG text, PDF Info, ID3, ZIP core.xml, HTML head.

  Cannot claim the body. A packet can lie or be stripped.

• Name tokens

  Dates, copy marks, MAGPIE / USPTO locks — labels only.

  Cannot open interiors. A name is not a hash and not a shelf.

• Hash

  SHA-256 of the bytes present.

  Cannot describe. A digest is not a reading.