cell phone anonymity

[Steve Mynott]

Lucky Green <shamrock at cypherpunks.to> writes:

> GSM phones do indeed broadcast their International Mobile Equipment Number
> (IMEI). The IMIE is hardcoded into the firmware of each phone. Changing the
> IMIE is possible, but not from the UI. Recently, the manufacturers have
> announced that they will make it even more difficult to alter IMEI's in the
> future.

The IMEI is displayed by *#06# on GSM phones and isn't broadcast.

GSM phones broadcast a temporary version of the IMEI called TMSI
(Temporary Mobile Subscriber Identity) rather than the IMEI directly
for privacy reasons (!)  The Nokia phones with Net Monitor mode will
display the current TMSI.

See for example,

GSM Security and Encryption

http://www3.l0pht.com/~oblivion/blkcrwl/cell/gsm/gsm-secur/gsm-secur.html

-- 
1024/D9C69DF9 steve mynott steve at tightrope.demon.co.uk

    only two things are infinite, the universe and human stupidity, and i'm
not sure about the former. --albert einstein