Difference between revisions of "DSiWare Exports"

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DSiWare exported from 3DS use [[Nand/private/movable.sed|keyslots]] initialized by movable.sed. Each section is encrypted with AES-CBC.
 
DSiWare exported from 3DS use [[Nand/private/movable.sed|keyslots]] initialized by movable.sed. Each section is encrypted with AES-CBC.
  
−
The content sections are ordered the same way as DSi: TMD, SRL from content0, <content1-7 for format v2>, savegame, and banner.sav.(ContentX here is the .app data from TWL-NAND /title)
+
The content sections are ordered the same way as DSi: TMD, SRL from content0, <content1-7 for format v2>, savegame, and banner.sav.(ContentX here is the .app data from TWL-NAND /title) The DSiWare export type is specified by [[AMPXI:ExportDSiWare]], this field is also used to specify the format version. For NATIVE_FIRM versions where this DSiWare type field is unused, format version v1 is used. When this field is used, format version v1 is used for DSiWare type value 13, otherwise v2 is used.
  
 
=Block Metadata=
 
=Block Metadata=
Line 22: Line 22:
  
 
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, however it's unknown how this hash is calculated. This hash used for generating the MAC is also stored in the footer.
 
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, however it's unknown how this hash is calculated. This hash used for generating the MAC is also stored in the footer.
 +
 +
=Footer=
 +
{| class="wikitable" border="1"
 +
|-
 +
!  Offset
 +
!  Size
 +
!  Description
 +
|-
 +
| 0x0
 +
| X
 +
| SHA-256 hashes over the banner, header, and content sections.
 +
|-
 +
| 0x0 + X
 +
| 0x3C
 +
| ECDSA signature over the previous data, signed by the AP cert?
 +
|-
 +
| 0x3C + X
 +
| 0x180
 +
| ECDSA "APXXXXXXXXXXXXXXXX" cert signed by the [[CTCert]], where X is random lowercase ASCII hex data.
 +
|-
 +
| 0x1BC + X
 +
| 0x180
 +
| ECDSA [[CTCert]]
 +
|-
 +
| 0x33C + X
 +
| 0x4
 +
| Uninitialized padding.
 +
|}
 +
 +
These hashes are the same hashes used for generating each section's MAC stored in the metadata block. For format version v1, X is 0xC0. For format version v2, X is at least 0x1A0.
  
 
=File Structure v1=
 
=File Structure v1=
Line 39: Line 69:
 
|-
 
|-
 
| 0x40E0
 
| 0x40E0
−
| 0x420
+
| 0x340 + X, where X is the total size of the hashes stored in the footer.
 
| Footer section
 
| Footer section
 
|-
 
|-
−
| 0x4500
+
| 0x40E0 + footer_size
 
|  
 
|  
 
| Data for the 4 content sections are stored here.
 
| Data for the 4 content sections are stored here.
Line 98: Line 128:
 
| Padding?
 
| Padding?
 
|}
 
|}
−
 
−
==Footer==
 
−
{| class="wikitable" border="1"
 
−
|-
 
−
!  Offset
 
−
!  Size
 
−
!  Description
 
−
|-
 
−
| 0x0
 
−
| 0x20
 
−
| SHA-256 hash over the banner.
 
−
|-
 
−
| 0x20
 
−
| 0x20
 
−
| SHA-256 hash over the header.
 
−
|-
 
−
| 0x40
 
−
| 0x80
 
−
| SHA-256 hashes over the 4 content sections, when a content section doesn't exist the corresponding hash is uninitialized.
 
−
|-
 
−
| 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.
 
−
|}
 
−
 
−
These hashes are the same hashes used for generating each section's MAC stored in the metadata block.
 
  
 
=File Structure v2=
 
=File Structure v2=
Line 153: Line 145:
 
|-
 
|-
 
| 0x4130
 
| 0x4130
−
| ?
+
| 0x340 + X, where X is the total size of the hashes stored in the footer.
 
| Footer section
 
| Footer section
 
|-
 
|-
−
|  
+
| 0x4130 + footer_size
 
|  
 
|  
 
| Data for the 11 content sections are stored here.
 
| Data for the 11 content sections are stored here.
Line 211: Line 203:
 
| 0x0E
 
| 0x0E
 
| Padding?
 
| Padding?
−
|}
 
−
 
−
==Footer==
 
−
{| class="wikitable" border="1"
 
−
|-
 
−
!  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.
 
 
|}
 
|}

Revision as of 18:12, 24 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.

The content sections are ordered the same way as DSi: TMD, SRL from content0, <content1-7 for format v2>, savegame, and banner.sav.(ContentX here is the .app data from TWL-NAND /title) The DSiWare export type is specified by AMPXI:ExportDSiWare, this field is also used to specify the format version. For NATIVE_FIRM versions where this DSiWare type field is unused, format version v1 is used. When this field is used, format version v1 is used for DSiWare type value 13, otherwise v2 is used.

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, however it's unknown how this hash is calculated. This hash used for generating the MAC is also stored in the footer.

Footer

Offset Size Description
0x0 X SHA-256 hashes over the banner, header, and content sections.
0x0 + X 0x3C ECDSA signature over the previous data, signed by the AP cert?
0x3C + X 0x180 ECDSA "APXXXXXXXXXXXXXXXX" cert signed by the CTCert, where X is random lowercase ASCII hex data.
0x1BC + X 0x180 ECDSA CTCert
0x33C + X 0x4 Uninitialized padding.

These hashes are the same hashes used for generating each section's MAC stored in the metadata block. For format version v1, X is 0xC0. For format version v2, X is at least 0x1A0.

File Structure v1

Offset Size Description
0x0 0x4020 Banner section
0x4020 0xC0 Header section
0x40E0 0x340 + X, where X is the total size of the hashes stored in the footer. Footer section
0x40E0 + footer_size 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 Byte-swapped titleID from the TWL TMD.
0x40 0x8 ?
0x48 0x10 u32 payload sizes for the 4 content sections.
0x58 0x4 ?
0x5C 0x3E Data from the TWL TMD reserved section. Only the first 0x20-bytes from the TWL TMD is written here, the rest is uninitialized.
0x9A 0x6 Padding?

File Structure v2

Offset Size Description
0x0 0x4020 Banner section
0x4020 0x110 Header section
0x4130 0x340 + X, where X is the total size of the hashes stored in the footer. Footer section
0x4130 + footer_size Data for the 11 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 Byte-swapped titleID from the TWL TMD.
0x40 0x8 ?
0x48 0x2C u32 payload sizes for the 11 content sections.
0x74 0x30 ?
0xA4 0x3E Data from the TWL TMD reserved section. Only the first 0x20-bytes from the TWL TMD is written here, the rest is uninitialized.
0xE2 0x0E Padding?
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