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7-Zip method IDs (4.65)

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Each compression or crypto method in 7z has unique binary value (ID).

The length of ID in bytes is arbitrary but it can not exceed 63 bits (8 bytes).



If you want to add some new ID, you have two ways:

1) Write request for allocating IDs to 7-zip developers.

2) Generate 8-bytes ID:



    3F ZZ ZZ ZZ ZZ ZZ MM MM 



    3F              - Prefix for random IDs (1 byte)

    ZZ ZZ ZZ ZZ ZZ  - Developer ID (5 bytes). Use real random bytes. 

                      

    MM MM           - Method ID (2 bytes)



    You can notify 7-Zip developers about your Developer ID / Method ID.



    Note: Use new ID only if old codec can not decode data encoded with new version.





List of defined IDs

-------------------

      

00 - Copy



02 - Common

   03 Swap

      - 2 Swap2

      - 4 Swap4



03 - 7z

   01 - LZMA

      01 - Version

  

   03 - Branch

      01 - x86

         03  - BCJ

         1B  - BCJ2

      02 - PPC

         05 - PPC (Big Endian)

      03 - Alpha

         01 - Alpha

      04 - IA64

         01 - IA64

      05 - ARM

         01 - ARM

      06 - M68

         05 - M68 (Big Endian)

      07 - ARM Thumb

         01 - ARMT

      08 - SPARC

         05 - SPARC



   04 - PPMD

      01 - Version



   7F -

      01 - experimental methods.





04 - Misc

   00 - Reserved

   01 - Zip

      00 - Copy (not used). Use {00} instead

      01 - Shrink

      06 - Implode

      08 - Deflate

      09 - Deflate64

      12 - BZip2 (not used). Use {04 02 02} instead

   02 - BZip

      02 - BZip2

   03 - Rar

      01 - Rar15

      02 - Rar20

      03 - Rar29

   04 - Arj

      01 - Arj (1,2,3)

      02 - Arj 4

   05 - Z

   06 - Lzh

   07 - Reserved for 7z

   08 - Cab

   09 - NSIS

      01 - DeflateNSIS

      02 - BZip2NSIS





06 - Crypto 

   00 - 

   01 - AES

      0x - AES-128

      4x - AES-192

      8x - AES-256

      Cx - AES



      x0 - ECB

      x1 - CBC

      x2 - CFB

      x3 - OFB



   07 - Reserved

   0F - Reserved



   F0 - Misc Ciphers (Real Ciphers without hashing algo)



   F1 - Misc Ciphers (Combine)

      01 - Zip

         01 - Main Zip crypto algo

      03 - RAR

         02 - 

         03 - Rar29 AES-128 + (modified SHA-1)

      07 - 7z

         01 - AES-256 + SHA-256



07 - Hash (subject to change)

   00 - 

   01 - CRC

   02 - SHA-1

   03 - SHA-256

   04 - SHA-384

   05 - SHA-512



   F0 - Misc Hash



   F1 - Misc

      03 - RAR

         03 - Rar29 Password Hashing (modified SHA1)

      07 - 7z 

         01 - SHA-256 Password Hashing

    

   





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