Ticket

Tickets are found in many encrypted files used by the Wii (e.g. WAD Files or Wiidiscs). They contain the encrypted AES "title key" and the Title ID of the data and are signed by a certificate from a certificate chain (which usually is the same for all titles and stored somewhere on the NAND). So far only tickets with RSA-2048 signatures have been seen. (Discs will only work with those signatures because the size of partition ticket is always 0x2a4)

File structure

Start	End	Length	Description
0x0000	0x0003	0x04	Signature type (always 0x10001 for RSA-2048)
0x0004	0x0103	0x100	Signature by a certificate's key (everything after this field is covered by this signature)
0x0104	0x013f	0x3b	Padding (Always 0)
0x0140	0x017f	0x40	Signature issuer
0x0180	0x01be	0x3f	Unknown (0, unless it is a VC game)
0x01bf	0x01ce	0x10	Encrypted title key
0x01cf	0x01db	0x0d	Unknown
0x01dc	0x01e3	0x08	Title ID / Initialization Vector (IV) used for AES-CBC encryption
0x01e4	0x01f0	0x0d	Unknown
0x01f1	0x01f1	0x01	Common Key index (1 = Korean Common key, 0 = "normal" Common key)
0x01f2	0x0221	0x30	Unknown. Is all 0 for non-VC, for VC, all 0 except last byte is 1.
0x0222	0x0241	0x20	Always 0xFF (?)
0x0242	0x0243	0x02	Padding (Always 0)
0x0244	0x0247	0x04	Enable time limit (1 = Enabled, 0 = Disabled)
0x0248	0x0249	0x02	Time limit (Seconds)
0x024a	0x02a3	0x5a	Padding (Always 0)

To get the title key decrypt the 16 bytes at offset 0x1bf with the Common Key using the Title ID (offset 0x1dc) as the initialization vector (the last 8 bytes of the IV should be zero).