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.

Ticket 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:

0x000        Certificate Length (in bits)
0x004        Certificate Serial (usually 1)
0x008        Public Key Length (in bits)
0x00c        Public Key Exponent
0x010-0x090  Public Key (RSA Key 3)
0x090-0x110  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)
0x1B8-...    Table of "policies" (netlock)

Attached to the decrypted ticket is a certificate (0x80 byte) signed with the RSA key 3 at 0x010.

Policy Table Layout

0x0          Total length of the policy table in bytes
<Policy Item>

An item is 12 byte in size and has this structure:

0x0-0x2      ID
0x2-0x4      type?
0x4-0xC      IMSI mask

Each nibble of a mask corresponds to a number - the wildcard is encoded as 0xE.

AT&T USA

IMSI Mask
310150?????????
310170?????????
310410?????????
311180?????????
310980?????????

This is an iPhone 3GS from AT&T.

T-Mobile Germany

IMSI Mask
26201??????????
26201??????????
26201??????????

This is an iPhone 3G from T-Mobile Germany.

Factory Unlocked Device

IMSI Mask
???????????????

Obligatory.