Ticket

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Tickets are a format used to store an encrypted titlekey (using 128-Bit AES-CBC). This format seems to be identical to DSi/Wii tickets.

Structure

All of the data in the file is represented in Big Endian.

Offset Size Description
0x000 Y Signature Data
Y 0x210 Ticket Data

Signature Data

The total size of this section is referred to as "Y" in the overall TMD structure. The signature is of the header of the TMD.

Offset Size Description
0x0 0x4 Signature Type
0x4 X Signature
0x4 + X Padding Aligning the signature data to 0x40 bytes

Signature Type

Value Signature Method Signature Size Padding Size
0x010000 RSA_4096 SHA1 (Unused for 3DS) 0x200 0x3C
0x010001 RSA_2048 SHA1 (Unused for 3DS) 0x100 0x3C
0x010002 Elliptic Curve with SHA1 (Unused for 3DS) 0x3C 0x40
0x010003 RSA_4096 SHA256 0x200 0x3C
0x010004 RSA_2048 SHA256 0x100 0x3C
0x010005 ECDSA with SHA256 0x3C 0x40

The hash for the signature is calculated over the Ticket Data.

Ticket Data

Offset Size Description
0x0 0x40 Issuer
0x40 0x3C ECDH data for console-unique eShop tickets.
0x7C 0x3 Unknown, first u8 is 0x01.
0x7F 0x10 Encrypted TitleKey
0x8F 0x1 Unknown
0x90 0x8 TicketID
0x98 0x4 Ticket consoleID
0x9C 0x8 TitleID
0xA4 0x2 Unknown
0xA6 0x2 Ticket title version, this title version is also stored in the TMD.
0xA8 0x8 Unused
0xB0 0x1 Unused
0xB1 0x1 Ticket common keyY index, usually 0x1 for retail system titles.
0xB2 0x2F Unused
0xE1 0x1 Unknown
0xE2 0x82 Unused
0x164 0x30 Unknown
0x194 0x7C Unused

The Signature Type is the same const as that in TMD.

The titlekey is decrypted by using the AES engine with the ticket common-key keyslot where the keyY is one of 6 keyYs loaded via the keyY index stored in the ticket. AES-CBC mode is used where the IV is the big-endian titleID. Note that on a retail unit index0 is a retail keyY, while on a dev-unit index0 is the dev common-key which is a normal-key.(On retail for these keyYs, the hardware key-scrambler is used)

Certificate Chain

Tickets retrieved from CDN/SOAP have a certificate chain appended at the end of the file. There are two certificates in this chain:

CERTIFICATE SIGNATURE TYPE RETAIL CERT NAME DEBUG CERT NAME DESCRIPTION
Ticket RSA-2048 XS0000000c XS00000009 Used to verify the Ticket signature
CA RSA-4096 CA00000003 CA00000004 Used to verify the Ticket Certificate

The CA certificate is issued by 'Root', the public key for which is stored in NATIVE_FIRM.

Some facts

  • CommonETicket (for short, cetk) is the name given to tickets for titles which aren't purchasable, like system titles.
  • CETK can be fetched through HTTP using the link to default update server, using the title's TMD URL where "cetk" is used instead of "tmd" for the URL. The 3DS NIM module retrieves system tickets via SOAP request GetCommonETicket.