File Signatures and Magic Numbers
Identify common file formats from their opening hexadecimal bytes.
| Format | Hex signature | Text/notes |
|---|---|---|
| 25 50 44 46 | %PDF |
|
| PNG | 89 50 4E 47 0D 0A 1A 0A | PNG image |
| JPEG | FF D8 FF | JPEG image family |
| GIF | 47 49 46 38 | GIF8 |
| ZIP / DOCX / XLSX / EPUB | 50 4B 03 04 | ZIP container; inspect internal files |
| GZIP | 1F 8B | Gzip-compressed data |
| 7-Zip | 37 7A BC AF 27 1C | 7z archive |
| RAR | 52 61 72 21 1A 07 | RAR archive |
| ELF | 7F 45 4C 46 | Unix/Linux executable or object |
| Windows EXE | 4D 5A | MZ; additional PE header later |
| WebP | 52 49 46 46 … 57 45 42 50 | RIFF container with WEBP marker |
| SQLite | 53 51 4C 69 74 65 20 66 | SQLite f |