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7-Zip method IDs (9.24)

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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



03 - Delta

04 - x86 (BCJ)

05 - PPC (Big Endian)

06 - IA64

07 - ARM (little endian)

08 - ARM Thumb (little endian)

09 - SPARC

21 - LZMA2

          

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

      10 - Imploding

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

      14 - LZMA

      60 - Jpeg

      61 - WavPack

      62 - PPMd

      63 - wzAES

   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 



   F0 - Ciphers without hashing algo



      01 - AES

         0x - AES-128

         4x - AES-192

         8x - AES-256

         Cx - AES



         x0 - ECB

         x1 - CBC

         x2 - CFB

         x3 - OFB

         x4 - CTR



   F1 - Combine Ciphers

      01 - Zip

         01 - Main Zip crypto algo

      03 - RAR

         02 - 

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

      07 - 7z

         01 - AES-256 + SHA-256





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End of document