WildcardTicket

The wildcard ticket is used for activating the baseband. It is stored in the file "/var/root/Library/Lockdown/activation_records/wildcard_record.plist". When activating an iPhone, the ticket is pulled from Apple's server and stored on the device. It contains all the information about sim-/netlocks. Factory- and carrier-unlocked devices receive a wildcard ticket with policies that permit all SIM cards.

Layout

0x0 Version number (=2 for iPhone 3G, 3GS)
0x4 Encrypted Ticket

The ticket is decrypted with TEA in CBC mode using a key hashed from the norID, chipID, IMEI and a salt. The layout of the decrypted ticket looks like this:

0x00        Certificate Length (in bits)
0x04        Certificate Serial (usually 1)
0x08        Public Key Length (in bits)
0x0c        Public Key Exponent
0x10-0x90   Public Key (RSA Key 3)
0x90-0x110  Additional Public Key - not in use 
0x110-0x190 Certificate of the first 0x110 bytes signed with rsa_key2
0x190-0x19B ICCID mask (relevant bits for simlock)
0x19C-0x1A3 IMEI
0x1A4-0x1B7 Hash of several hardware IDs (IMEI, norID, chipID)
0x1B7-      Table of "policies" (netlock)

Attached to the decrypted ticket is a certificate (0x80 byte) signed with the RSA key 3 at 0x10.