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ixalon
Joined: 17 Jul 2006
Posts: 6
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 Posted: Mon Jul 17, 2006 11:54 pm Post subject: Compression/Encryption in LocationFree LFR files? |
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Hi guys,
I'm getting annoyed with the lack of updates to the LocationFree remote data for the PSP compared to that of the client for the PC - so I'm taking a stab at working out the file format of the LFR files you put on your memorystick to update the remote control code data. Hopefully this will allow a tool where you convert the plain-text RC data files sony has available for download for the PC LocationFree client to the binary LFR format for use on the PSP.
So far I've got:
| Code: | struct lfrm_header {
char magic[4]; // LFRM
short version; // 0x00 0x01
short unknown1; // 0x00 0x00
};
struct lfrm_block {
unsigned int offset;
unsigned int length;
};
// pseudo code:
// read lfrm_header
// read lfrm_block until offset==0x0
// block 0 looks like it's IR data
// block 1 looks like manufacturer -> model structure (uint32 followed by null terminated string * n1)
// block 2 looks like a stringtable (null terminated string * n2)
// block 3 is zero-length
// block 4 is zero-length
// block 5 looks compressed and/or encrypted |
I'm stuck on block 5, the files for each region have the same 48 byte header, then the rest of the block looks like compressed/encrypted data. Does anyone know which encryption/compression algorithms the PSP tends to use which would use a 48 byte header?
This 48 byte header doesn't contain any obvious structures and doesn't change even when the rest of the data in the file changes. Either the compression/encryption algorithm writes 48 byte chunks and the first n-bytes of plaintext data is the same for each file or it's the key used to decrypt the remaning data.
The 48 bytes:
| Code: | B7 E5 3B 7C 18 9C 09 44 6C 46 CD 9B 15 C9 FA 39
E3 54 4B 08 06 26 FA 2B F1 ED 66 99 8D 2F D8 63
43 E8 FB 97 06 1E 18 55 2C D8 CA F8 95 9F C5 FA |
Cheers,
ix |
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[FireFly]
Joined: 06 Aug 2006
Posts: 2
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| Posted: Sat Jun 30, 2007 5:40 am Post subject: |
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| The remote control codes in the plain-text RC data files are actually encrypted. Fortunately I was able to debug the player software on PC and figure everything out. The reason why I did this was so that I could generate LocationFree remote control codes for controlling Windows Media Center through a Pinnacle TV card. If anyone wants to use a LF-B1 base station for controlling an unsupported infared device, PM me. |
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