Magic Bytes
Some types of files have fixed bytes at the beginning, which can be used to determine the file type. These bytes are also known as "magic numbers". For example, the magic number for a class file is "CAFEBABE".
Description | Extension | Magic Number |
---|---|---|
Adobe Illustrator | .ai | 25 50 44 46 [%PDF] |
Bitmap graphic | .bmp | 42 4D [BM] |
Class File | .class | CA FE BA BE |
JPEG graphic file | .jpg | FF D8 |
JPEG 2000 graphic file | .jp2 | 0000000C6A5020200D0A [....jP..] |
GIF graphic file | .gif | 47 49 46 38 [GIF89] |
TIF graphic file | .tif | 49 49 [II] |
PNG graphic file | .png | 89 50 4E 47 .PNG |
WAV audio file | .wav | 52 49 46 46 RIFF |
ELF Linux EXE | .elf | 7F 45 4C 46 .ELF |
Photoshop Graphics | .psd | 38 42 50 53 [8BPS] |
Windows Meta File | .wmf | D7 CD C6 9A |
MIDI file | .mid | 4D 54 68 64 [MThd] |
Icon file | .ico | 00 00 01 00 |
MP3 file with ID3 identity tag | .mp3 | 49 44 33 [ID3] |
AVI video file | .avi | 52 49 46 46 [RIFF] |
Flash Shockwave | .swf | 46 57 53 [FWS] |
Flash Video | .flv | 46 4C 56 [FLV] |
Mpeg 4 video file | .mp4 | 00 00 00 18 66 74 79 70 6D 70 34 32 [....ftypmp42] |
MOV video file | .mov | 6D 6F 6F 76 [....moov] |
Windows Video file | .wmv | 30 26 B2 75 8E 66 CF |
Windows Audio file | .wma | 30 26 B2 75 8E 66 CF |
PKZip | .zip | 50 4B 03 04 [PK] |
GZip | .gz | 1F 8B 08 |
Tar file | .tar | 75 73 74 61 72 |
Microsoft Installer | .msi | D0 CF 11 E0 A1 B1 1A E1 |
Object Code File | .obj | 4C 01 |
Dynamic Library | .dll | 4D 5A [MZ] |
CAB Installer file | .cab | 4D 53 43 46 [MSCF] |
Executable file | .exe | 4D 5A [MZ] |
RAR file | .rar | 52 61 72 21 1A 07 00 [Rar!...] |
SYS file | .sys | 4D 5A [MZ] |
Help file | .hlp | 3F 5F 03 00 [?_..] |
VMWare Disk file | .vmdk | 4B 44 4D 56 [KDMV] |
Outlook Post Office file | .pst | 21 42 44 4E 42 [!BDNB] |
PDF Document | 25 50 44 46 [%PDF] | |
Word Document | .doc | D0 CF 11 E0 A1 B1 1A E1 |
RTF Document | .rtf | 7B 5C 72 74 66 31 [{ tf1] |
Excel Document | .xls | D0 CF 11 E0 A1 B1 1A E1 |
PowerPoint Document | .ppt | D0 CF 11 E0 A1 B1 1A E1 |
Visio Document | .vsd | D0 CF 11 E0 A1 B1 1A E1 |
DOCX (Office 2010) | .docx | 50 4B 03 04 [PK] |
XLSX (Office 2010) | .xlsx | 50 4B 03 04 [PK] |
PPTX (Office 2010) | .pptx | 50 4B 03 04 [PK] |
Microsoft Database | .mdb | 53 74 61 6E 64 61 72 64 20 4A 65 74 |
Postcript File | .ps | 25 21 [%!] |
Outlook Message File | .msg | D0 CF 11 E0 A1 B1 1A E1 |
EPS File | .eps | 25 21 50 53 2D 41 64 6F 62 65 2D 33 2E 30 20 45 50 53 46 2D 33 20 30 |
Jar File | .jar | 50 4B 03 04 14 00 08 00 08 00 |
SLN File | .sln | 4D 69 63 72 6F 73 6F 66 74 20 56 69 73 75 61 6C 20 53 74 75 64 69 6F 20 53 6F 6C 75 74 69 6F 6E 20 46 69 6C 65 |
Zlib File | .zlib | 78 9C |
SDF File | .sdf | 78 9C |
Get magic bytes using PHP
function magic_bytes($path, $position = 0, $bytes = 4)
{
if (!file_exists($path)) {
return null;
}
$handle = fopen($path, 'rb');
fseek($handle, $position);
$bytes = bin2hex(fread($handle, $bytes));
fclose($handle);
return $bytes;
}
Get magic bytes using Java
public static String getMagicBytes(String filePath, int position, int bytes) {
try {
byte[] data = Files.readAllBytes(Paths.get(filePath));
ByteBuffer bb = ByteBuffer.wrap(data);
bb.position(position);
StringBuilder sb = new StringBuilder();
for(int i=0; i
Get magic bytes using Python3
def get_magic_bytes(file_path, position=0, nbytes=4):
try:
with open(file_path, 'rb') as file:
file.seek(position)
magic_bytes = file.read(nbytes)
return magic_bytes.hex()
except FileNotFoundError:
print(f"File {file_path} not found.")
return None
Get magic bytes using Golang
import (
"fmt"
"os"
)
func getMagicBytes(filePath string, position, nbytes int) (string, error) {
file, err := os.Open(filePath)
if err != nil {
return "", err
}
defer file.Close()
bytes := make([]byte, nbytes)
_, err = file.ReadAt(bytes, int64(position))
if err != nil {
return "", err
}
return fmt.Sprintf("%x", bytes), nil
}
Get magic bytes using Dart
import 'dart:async';
import 'dart:io';
import 'dart:convert';
Future getMagicBytes(String path, [int position = 0, int nbytes = 4]) async {
var file = new File(path);
if (!await file.exists()) {
print("File does not exist.");
return null;
}
RandomAccessFile openedFile = await file.open(mode: FileMode.read);
await openedFile.setPosition(position);
List magicBytes = [];
for (int i = 0; i < nbytes; i++) {
magicBytes.add(await openedFile.readByte());
}
await openedFile.close();
return hex.encode(magicBytes);
}
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