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