.TORRENT file signature
A BitTorrent file file begins with the bytes 64 38 3A 61 6E 6E 6F 75 6E 63 65 (d8:announce in ASCII) at the start of the file. The signature is the same whatever the file is named, which is why a renamed or extensionless TORRENT file is still recognisable.
Signature
| Offset | Hex | ASCII |
|---|---|---|
| 0 | 64 38 3A 61 6E 6E 6F 75 6E 63 65Bencoded dictionary; d10:created by is another common opening. | d8:announce |
MIME type: application/x-bittorrent · usual extensions: .torrent
How to check a file's signature
Without installing anything: drop the file on our detector. It reads the bytes in your browser and shows the hex dump alongside the verdict; nothing is uploaded.
macOS and Linux (Terminal):
xxd -l 32 file.torrent
file file.torrentWindows (PowerShell):
Format-Hex -Path file.torrent -Count 32If the bytes do not match
A file named .torrent whose first bytes are something else is not a TORRENT file. The common explanations are a wrong or deliberately misleading extension, a download that saved an HTML error page instead of the file, or a container such as ZIP wrapping the real content. The detector reports what the bytes say; the TORRENT guide explains what a genuine file should contain.