Difference between revisions of "DSiWare Exports"

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|-
 
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| 0x4
 
| 0x4
| 0x4
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| 0x2
| Normally zero?
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| Byte-swapped groupID from the TWL [[TMD]].
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| 0x6
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| 0x2
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| Byte-swapped title version from the TWL [[TMD]].
 
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| 0x5C
 
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| 0x3E
 
| 0x3E
| Data from the TWL title [[TMD]] 0x3E-byte reserved section.
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| Data from the TWL [[TMD]] 0x3E-byte reserved section.
 
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| 0x9A
 
| 0x9A

Revision as of 07:34, 23 April 2013

The DSiWare exported from a 3DS is located at "sdmc:/Nintendo 3DS/<ID0>/<ID1>/Nintendo DSiWare". Filenames are same format as DSi: "<TitleID-Low>.bin". The below sizes include the 0x20-byte block metadata.

DSiWare exported from 3DS use keyslots initialized by movable.sed. Each section is encrypted with AES-CBC.

Block Metadata

Offset Size Description
0x0 0x10 AES MAC over a SHA-256 hash
0x10 0x10 IV, generated by the RNG.

Each section begins with the payload encrypted data, followed by this block metadata. The hash used for the MAC is calculated over the the cleartext payload, this hash is calculated the same way as the section hashes stored in the footer.

File Structure v1

Offset Size Description
0x0 0x4020 Banner section
0x4020 0xC0 Header section
0x40E0 0x420 Footer section
0x4500 Data for the 4 content sections are stored here.

Header

Offset Size Description
0x0 0x4 Magic number 0x54444633, "3FDT".
0x4 0x2 Byte-swapped groupID from the TWL TMD.
0x6 0x2 Byte-swapped title version from the TWL TMD.
0x8 0x20 SHA-256 hash calculated over the encrypted movable.sed.
0x28 0x10 Encrypted AES block from encrypting an all-zero 0x10-byte block with AES-CBC, where the IV is all-zero.
0x38 0x8 TWL TitleID for the exported title.
0x40 0x8 ?
0x48 0x10 u32 payload sizes for each content section.
0x58 0x4 ?
0x5C 0x3E Data from the TWL TMD 0x3E-byte reserved section.
0x9A 0x6 Padding?

Footer

Offset Size Description
0x0 0xC0 SHA-256 hashes over each section, it's unknown how these are calculated.
0xC0 0x3C ECDSA signature over the previous data, signed by the AP cert?
0xFC 0x180 ECDSA "APXXXXXXXXXXXXXXXX" cert signed by the CTCert, where X is random lowercase ASCII hex data.
0x27C 0x180 ECDSA CTCert
0x3FC 0x4 Uninitialized padding.

File Structure v2

Offset Size Description
0x0 0x4020 Banner section
0x4020 0xC0 Header section
0x40E0 ? Footer section
Data for the 4 content sections are stored here.

Header

Offset Size Description
0x0 0x4 Magic number possibly?
0x4 0x4 ?
0x8 0x38 Unknown
0x38 0x8 TWL TitleID for the exported title.
0x40 0x60 ?

Footer

Offset Size Description
0x0 0xD0 ?
0xD0 0xE0 Normally all-zero?
0x1B0 0x20 SHA256 hash?
0x1D0 0x20 Normally all-zero?
0x1F0 0x3C ECDSA signature over the previous data, signed by the AP cert?
0x22C 0x180 ECDSA "APXXXXXXXXXXXXXXXX" cert signed by the CTCert, where X is random lowercase ASCII hex data.
0x3AC 0x54 ECDSA certificate, the last 0x14-bytes here are all-zero.