.DEB file signature
A Debian binary package file begins with the bytes 21 3C 61 72 63 68 3E 0A (!<arch>\n 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 DEB file is still recognisable.
Signature
| Offset | Hex | ASCII |
|---|---|---|
| 0 | 21 3C 61 72 63 68 3E 0AA Unix ar archive; the first member is named debian-binary. | !<arch>\n |
MIME type: application/vnd.debian.binary-package · usual extensions: .deb
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.deb
file file.debWindows (PowerShell):
Format-Hex -Path file.deb -Count 32If the bytes do not match
A file named .deb whose first bytes are something else is not a DEB 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 DEB guide explains what a genuine file should contain.