Magic numbers for different file types

Source: Internet
Author: User
Tags posix

Here, we refer to magic numbers for different file types. It specifies the first few bytes of a file that are used to uniquely distinguish other file types. With these magic numbers, we can easily differentiate different files, which makes programming easier, because I reduce the time it takes for us to differentiate the file type of a file.

For example, some bytes starting with a jpeg file may be similar to this"Ffd8 ffe0 0010 4a46 4946 0001 0101 ...... Jfif ..... G", Here"Ffd8"It indicates that this file is a jpeg file ,"Ffe0"Indicates that this is a jfif type structure.

The following example shows some common file types, as well as several starting bytes used to determine the file type and the ASCII numbers on the pointed point:

Image files
File Type Extension Hexadecimal number
XX indicates the variable.
ASCII number
. = Not ASCII characters
Bitmap format . BMP 42 4D BM
Fits format . Fits 53 49 4D 50 4C 45 Simple
GIF format . Gif 47 49 46 38 Gif8
Graphics Kernel System . GKS 47 4B 53 4D Gksm
Iris RGB format . RGB 01 da ..
ITC (cmu wm) Format . ITC F1 00 40 bb ....
JPEG file Interchange Format . Jpg FF D8 FF E0 ....
NIF (Navy TIFF) . NIF 49 49 4E 31 Iin1
PM format . PM 56 49 45 57 View
PNG format . PNG 89 50 4E 47 . PNG
Postscript format . [E] PS 25 21 %!
Sun rasterfile . RAS 59 A6 6a 95 Y. J.
Targa format . TGA Xx ...
Tiff format (Motorola-big endian) . Tif 4d 4D 00 2a Mm .*
Tiff format (Intel-little endian) . Tif 49 49 2a 00 II *.
X11 bitmap format . Xbm Xx  
Xcf gimp file structure . Xcf 67 69 6D 70 20 78 63 66 20 76 Gimp xcf
Xfig format . Fig 23 46 49 47 # Fig
XPM format . XPM 2f 2a 20 58 50 4D 20 2a 2f /* XPM */
Compressed file
File Type Extension Hexadecimal number
XX indicates the variable.
ASCII number
. = Not ASCII characters
Bzip . Bz 42 5A BZ
Compress . Z 1f 9d ..
GZIP format . GZ 1f 8b ..
PKZIP format . Zip 50 4B 03 04 PK ..
Archive files
File Type Extension Hexadecimal number
XX indicates the variable.
ASCII number
. = Not ASCII characters
Tar (pre-POSIX) . Tar Xx (A filename)
Tar (POSIX) . Tar 75 73 74 61 72 USTAR (offset by 257 bytes)
Executable files
File Type Extension Hexadecimal number
XX indicates the variable.
ASCII number
. = Not ASCII characters
MS-DOS, OS/2 or MS windows   4d 5A MZ
UNIX elf   7f 45 4C 46 . Elf
Other files
File Type Extension Hexadecimal number
XX indicates the variable.
ASCII number
. = Not ASCII characters
PGP Public Ring   99 00 ..
PGP security ring   95 01 ..
PGP security ring   95 00 ..
PGP encrypted data   A6 00 Invalid.

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