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The initial discussion of this thread was done in zenhax I linked the original topic from zenhax This post completed the early preliminary research on this game, and at that time, the extraction of files was basically implemented. In order to make the post more practical and give more topics to discuss, I will set the topic of this post as a Messiah engine file format research, which can discuss more Messiah-related games, not just for ace racer During these times, the engine version has been upgraded many times, and the index table has been updated. Now the hash names of some games have been encrypted in the index table. The index table of each game is basically the same, but it is different. As far as I know, there should be more than three different versions of the index table. 1. Index Version 1 If they have not been updated, these indexes should be the earliest version, without any fiddling, and are also the easiest version to study. You can use netease_mpk_v2.bms to disassemble it //Some new games still use these initial index versions, but have added new compression formats. If you are familiar with bms scripts or python scripts, you can add decompression by yourself, and others remain unchanged 2. Index version 2 The index of this structure is still very simple, but the file name seems to have been specially processed, and normal file names will not be generated in the index. Under the same version of the index, the number of bytes used by different games is also different. Some games take up 20 bytes in one file, while some games take up 24 bytes in one file 3. Index version 3 I seem to have only seen this version of the index on Knives Out games. A large part of the index is overwritten by 0, the file name is not encrypted, the size and offset can also be read, but the index structure is very messy, I can only complete manual extraction, and have not written an automated script (from the index after hot update) 4/Index version 4? Now some index files seem to be replaced directly by database file types, so I directly call them version 4, the entries of these index files are stored in the database file, and after parsing from the database, it may be necessary to make some fiddling to allow the script to extract correctly More types are also added for compressed files, I'm trying to understand all compressions to support more games 1.ZZZ4 (lz4 compression) 2.ZZZZ (lzo1x compression) 3.ZZZX (seems to be encrypted lz4) has a script where_winds_meet_mpk.bms that can handle this compression, but the script is outdated, not sure if the key is outdated 4.LZMA (lzma compression) 5.ZSTD (zstd compression) 6.1084 (exclusive or lz4 compression) 7.108D (zstd compression) 8.E206 (corrupted zlib compression) 9.EZST (Unknown compression This post will discuss the index structure, compression type, and other related files about the engine