Ticket

Tickets are a format used to store an encrypted titlekey (using 128-Bit AES-CBC). With 3DS, the Ticket format was updated (now v1) from Wii/DSi format (v0).

Structure

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

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

Y denotes the total size of the "Signature Data" section and depends on the signature type.

Signature Data

The signature is of the ticket header.

Offset	Size	Description
0x0	0x4	Signature Type
0x4	X	Signature
0x4 + X		Padding to align 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	ECC PublicKey
0x7C	0x1	Version (For 3DS this is always 1)
0x7D	0x1	CaCrlVersion
0x7E	0x1	SignerCrlVersion
0x7F	0x10	TitleKey (normal-key encrypted using one of the common keyYs; see below)
0x8F	0x1	Reserved
0x90	0x8	TicketID
0x98	0x4	ConsoleID
0x9C	0x8	TitleID
0xA4	0x2	Reserved
0xA6	0x2	Ticket title version
0xA8	0x8	Reserved
0xB0	0x1	License Type
0xB1	0x1	Index to the common keyY used for this ticket, usually 0x1 for retail system titles; see below.
0xB2	0x2A	Reserved
0xDC	0x4	eShop Account ID?
0xE0	0x1	Reserved
0xE1	0x1	Audit
0xE2	0x42	Reserved
0x124	0x40	Limits
0x164	X	Content Index

• For v0 of the format, see here

• The Ticket Title Version is generally the same as the title version stored in the Title Metadata. Although it doesn't have to match the TMD version to be valid.

• The titlekey is decrypted by using the AES engine with the ticket common-key keyslot. The keyY is selected through an index (ticket offset 0xB1) into a plaintext array of 6 keys ("common keyYs") stored in the data section of Process9. 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)

• The titlekey is used to decrypt content downloaded from the CDN using 128-bit AES-CBC with the content index (as big endian u16, padded with trailing zeroes) as the IV.

• In demos, the first u32 in the "Limits" section is 0x4, then the second u32 is the max-playcount.

• The Content Index of a ticket has its own size defined within itself, with seemingly a minimal of 20 bytes, the second u32 in big endian defines the full value of X.

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 are not available on the eShop, like system titles. As the name suggests, they are not unique tickets, the same ticket is common to each 3ds which has installed that title. This is in contrast to tickets for eShop content, which are generated prior to initial download, and are unique to 3ds it was generated for.

• 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 GetSystemCommonETicket instead of directly downloading the cetks with HTTPS. The cetks are also accessible via HTTP (even though the 3DS never accesses them like that).