Talk:Savegames: Difference between revisions

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Magic isn't always 0x080D6CE0, sometimes it is 0x080D6C80 or something in the like...

Unrelatedly, I wonder what kind of data unused blocks are mapped to (zeros or FF). Because those Rayman3D saves say that data goes up to 0xF000 (the end of the dewearleveled image), however there are usually no more than 4 blocks in use. --[[User:Luigi2us|Luigi2us]] 00:05, 1 February 2012 (CET)

[http://dl.dropbox.com/u/37418652/3DS/MH3G.sav|MH3G save file]

I think this game is also using the new save encryption.--Matyapiro31 09:47, 19 February 2012 (CET)

== Encryption method ==

@Yellows8, I think the old encryption is just [http://en.wikipedia.org/wiki/Block_cipher_modes_of_operation#Electronic_codebook_.28ECB.29 AES-ECB] which is the same as AES-CTR whose counter isn't progressing... --[[User:Elisherer|Elisherer]] 15:07, 25 March 2012 (CEST)

:It is *not* AES-ECB. If it were,(and Nintendo has *never* used AES-ECB *directly*) you would see the same encrypted 16-byte block for *every* all-zero 16-byte block. The CTR *does* increase, it just gets reset every X bytes. An encryption method only counts as direct AES-ECB only if the encrypted data is used as the AES input block, and the output block is used as the strait decrypted block. --[[User:Yellows8|Yellows8]] 18:31, 25 March 2012 (CEST)

== Hashes ==

@Yellows8, That's awesome! Can you explain a bit more about the buffer padding (maybe give an example) I want to add the foundings to 3dsexplorer and complete the saving algorithm (without the MAC signing ofcourse) --[[User:Elisherer|Elisherer]] 07:12, 3 September 2012 (CEST)

:Is it more clear with my last edit? The RomFS [https://github.com/3dshax/ctr/blob/master/ctrtool/ivfc.c IVFC] is basically identical to savegames, except savegames have the additional filesystem level.(Didn't realize that when I figured out the savegame hashes though) And it's not actually possible to generate the MAC yet with the AES engine, since the keyY for gamecard savegames is currently unknown. --[[User:Yellows8|Yellows8]] 16:57, 3 September 2012 (CEST)

::That's really interesting. I wonder what is the general idea here...Do savegames use the romFS structure.. --[[User:Elisherer|Elisherer]] 00:00, 4 September 2012 (CEST)

== Savegame keyY CardId ==

Are those two u32 cardIDs mentiond in keyY generation for the first version of savegamy encryption just ROM chip type ID repeated twice, like 45FA009045FA0090 or ROMID/EEPROMID combination? --[[User:Duke srg|Duke srg]] 10:43, 23 February 2015 (CET)

== File system ==

Data of one file in SAVE partition / filestore seems sometimes fragmented into several blocks, and BlockMap probably describes how to link and build them. Is this already known? And I think what is stored in BlockMap forms linked lists, and an entry is {uint32 previous_block; uint32 next_block; }. (Note that I was looking into CECD system savegame, which is the only savegame I looked, and which contains a relative complicated folder structure, where files and folders can be added and deleted frequently) --[[User:Wwylele|Wwylele]] ([[User talk:Wwylele|talk]]) 15:01, 18 August 2016 (CEST)

Also the SAVE partition looks very similar to [[Extdata#Filesystem|extdata VSXE partition]], especially the folder and file entries. --[[User:Wwylele|Wwylele]] ([[User talk:Wwylele|talk]]) 13:52, 19 August 2016 (CEST)

@@ Line 99: / Line 99: @@
 Magic isn't always 0x080D6CE0, sometimes it is 0x080D6C80 or something in the like...
 Unrelatedly, I wonder what kind of data unused blocks are mapped to (zeros or FF). Because those Rayman3D saves say that data goes up to 0xF000 (the end of the dewearleveled image), however there are usually no more than 4 blocks in use. --[[User:Luigi2us|Luigi2us]] 00:05, 1 February 2012 (CET)
+[http://dl.dropbox.com/u/37418652/3DS/MH3G.sav|MH3G save file]
+I think this game is also using the new save encryption.--Matyapiro31 09:47, 19 February 2012 (CET)
+== Encryption method ==
+@Yellows8, I think the old encryption is just [http://en.wikipedia.org/wiki/Block_cipher_modes_of_operation#Electronic_codebook_.28ECB.29 AES-ECB] which is the same as AES-CTR whose counter isn't progressing... --[[User:Elisherer|Elisherer]] 15:07, 25 March 2012 (CEST)
+:It is *not* AES-ECB. If it were,(and Nintendo has *never* used AES-ECB *directly*) you would see the same encrypted 16-byte block for *every* all-zero 16-byte block. The CTR *does* increase, it just gets reset every X bytes. An encryption method only counts as direct AES-ECB only if the encrypted data is used as the AES input block, and the output block is used as the strait decrypted block. --[[User:Yellows8|Yellows8]] 18:31, 25 March 2012 (CEST)
+== Hashes ==
+@Yellows8, That's awesome! Can you explain a bit more about the buffer padding (maybe give an example) I want to add the foundings to 3dsexplorer and complete the saving algorithm (without the MAC signing ofcourse) --[[User:Elisherer|Elisherer]] 07:12, 3 September 2012 (CEST)
+:Is it more clear with my last edit? The RomFS [https://github.com/3dshax/ctr/blob/master/ctrtool/ivfc.c IVFC] is basically identical to savegames, except savegames have the additional filesystem level.(Didn't realize that when I figured out the savegame hashes though) And it's not actually possible to generate the MAC yet with the AES engine, since the keyY for gamecard savegames is currently unknown. --[[User:Yellows8|Yellows8]] 16:57, 3 September 2012 (CEST)
+::That's really interesting. I wonder what is the general idea here...Do savegames use the romFS structure.. --[[User:Elisherer|Elisherer]] 00:00, 4 September 2012 (CEST)
+== Savegame keyY CardId ==
+Are those two u32 cardIDs mentiond in keyY generation for the first version of savegamy encryption just ROM chip type ID repeated twice, like 45FA009045FA0090 or ROMID/EEPROMID combination? --[[User:Duke srg|Duke srg]] 10:43, 23 February 2015 (CET)
+== File system ==
+Data of one file in SAVE partition / filestore seems sometimes fragmented into several blocks, and BlockMap probably describes how to link and build them. Is this already known? And I think what is stored in BlockMap forms linked lists, and an entry is {uint32 previous_block; uint32 next_block; }. (Note that I was looking into CECD system savegame, which is the only savegame I looked, and which contains a relative complicated folder structure, where files and folders can be added and deleted frequently) --[[User:Wwylele|Wwylele]] ([[User talk:Wwylele|talk]]) 15:01, 18 August 2016 (CEST)
+Also the SAVE partition looks very similar to [[Extdata#Filesystem|extdata VSXE partition]], especially the folder and file entries. --[[User:Wwylele|Wwylele]] ([[User talk:Wwylele|talk]]) 13:52, 19 August 2016 (CEST)