Signal rolls out a new privacy feature making it tougher to know a sender’s identity October 29, 2018 https://techcrunch.com/2018/10/29/signal-sealed-sender-feature-messaging-security/
IMEI is nothing special, just a serial number of your phone. Similar to MAC in networks NICs (and yes , some mobile chips support changing IMEI to any value). But IMSI that's in the SIM is the real deal. Is it possible to hide?
It's illegal to change IMSI. You need a recognized IMSI to make calls. So changing mainly means using someone else's. As in cloning a phone. And that'd mostly be used to evade charges, by having someone else pay them. Or for impersonating calls.
Yea...that's what I tought too... Changing IMEI is trivial (if phone does not support it directly and you don't want to hack your smartphone, then just get bunch of cheap disposable phones ... ) But IMSI needs cloning equipment like you said...unless one wants to start playing games with pre-paid SIMs... EDIT: Heh...Just now learned that there burner apps too that can give you extra phone numbers.... EDIT2: Here's an interesting propose from security researcher: https://phys.org/news/2016-11-sim-card-mobile.html In theory it would basically defeat fake towers (like stingrays) tracking you. EDIT3: The more I dig the more interesting this get. Apparently there are thing like Super SIM or Multi Super SIM (or what ever) where one physical card can have contents of several SIM cards.... Dang...now all I need is some of those for testing, a card reader and some software
