{
  "id": "magic/7z",
  "family": "magic",
  "slug": "7z",
  "title": "7-Zip signature (37 7A BC AF 27 1C)",
  "summary": "A 7-Zip archive begins with the 6-byte signature '7z' (0x37 0x7A) followed by the fixed bytes 0xBC 0xAF 0x27 0x1C, then a 2-byte format version.",
  "kind": "signature",
  "aliases": [
    "7z magic",
    "7-Zip"
  ],
  "status": "de-facto",
  "verification": "verified",
  "tier": "C",
  "source_url": "https://py7zr.readthedocs.io/en/latest/archive_format.html",
  "source_version": "7z archive format documentation (signature header '7z\\xbc\\xaf\\x27\\x1c')",
  "retrieved_date": "2026-05-29",
  "attribution": [
    {
      "claim_ref": "ext.magic_hex",
      "source_url": "https://py7zr.readthedocs.io/en/latest/archive_format.html",
      "source_version": "retrieved 2026-05-29",
      "note": "Signature header: kSignature = '7z' 0xBC 0xAF 0x27 0x1C, then 2-byte ArchiveVersion."
    },
    {
      "claim_ref": "ext.magic_hex",
      "source_url": "https://en.wikipedia.org/wiki/List_of_file_signatures",
      "source_version": "retrieved 2026-05-29",
      "note": "Corroborates 37 7A BC AF 27 1C as the 7-Zip signature."
    }
  ],
  "see_also": [
    "magic/zip",
    "magic/rar",
    "magic/gzip"
  ],
  "ext_type": "file-signature@1",
  "ext": {
    "magic_hex": "37 7A BC AF 27 1C",
    "offset": 0,
    "magic_ascii": "7z\\xbc\\xaf'\\x1c",
    "extensions": [
      "7z"
    ],
    "mime": "application/x-7z-compressed",
    "spec": "7z archive format",
    "notes": [
      "Bytes 0-1: '7z' (37 7A). Bytes 2-5: fixed BC AF 27 1C.",
      "Bytes 6-7: format version (e.g. 00 04).",
      "Followed by a start-header CRC and a pointer to the end header that holds the actual archive metadata."
    ]
  },
  "updated": "2026-05-29T00:00:00Z"
}