1 7-Zip method IDs for 7z and xz archives
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2 ---------------------------------------
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7 Each compression or crypto method in 7z is associated with unique binary value (ID).
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8 The length of ID in bytes is arbitrary but it can not exceed 63 bits (8 bytes).
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10 xz and 7z formats use same ID map.
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12 If you want to add some new ID, you have two ways:
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13 1) Write request for allocating IDs to 7-Zip developers.
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14 2) Generate 8-bytes ID:
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16 3F ZZ ZZ ZZ ZZ ZZ MM MM
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18 3F - Prefix for random IDs (1 byte)
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19 ZZ ZZ ZZ ZZ ZZ - Developer ID (5 bytes). Use real random bytes.
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21 MM MM - Method ID (2 bytes)
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23 You can notify 7-Zip developers about your Developer ID / Method ID.
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25 Note: Use new ID, if old codec can not decode data encoded with new version.
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35 05 - PPC (big-endian)
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37 07 - ARM (little-endian)
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38 08 - ARMT (little-endian)
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52 03 - [Branch Codecs]
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55 1B - BCJ2 (4 packed streams)
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57 05 - PPC (big-endian)
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63 01 - ARM (little-endian)
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65 05 - M68 (big-endian)
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67 01 - ARMT (little-endian)
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75 01 - experimental method.
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83 00 - Copy (not used. Use {00} instead)
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89 0C - BZip2 (not used. Use {040202} instead)
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90 0E - LZMA (LZMA-zip)
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94 62 - PPMd (PPMd-zip)
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114 07 - Reserved for 7z
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122 F7 - External codecs (that are not included to 7-Zip)
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125 10 xx - reserved (LZHAM)
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126 11 xx - reserved (Zstd)
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131 F0 - Ciphers without hashing algo
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145 F1 - Combine Ciphers
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148 01 - ZipCrypto (Main Zip crypto algo)
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152 03 - Rar29AES (AES-128 + modified SHA-1)
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155 01 - 7zAES (AES-256 + SHA-256)
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