iOS two factor authentication

[jpn]

hi

i travel frequently and have 4 SIMs that I use, depending on country.
2 of the cards are countries in which apple has implemented two factor authentication.
the other 2 are in countries where apple hasn't implemented it.

can you register more than 1 mobile number with two factor authentication?
does apple SMS its 4 digit passcode to all of the numbers associated with TFA, or just a primary one, or, just the last associated IMEI number that it has registered. or what?

also, apple says you need two of the following: password, the passcode SMSed to your mobile, or, the recovery key
but i read that the recovery key itself is a one time use recovery key (which seems impossible overkill but..) is this true? once used you need to get a new recovery key?

if apple could somehow allow a hardware keychain type of TFA device then I could use TFA but I do not hear anything about that. and kind of 20 year ago tech anyway at that.

lastly, with Yosemite, do you think that since the SMS will be able to be received by macs can I get the SMS on my mac? if apple sends the SMS to an iMessage associated address then I can get that SMS/iMessage no matter what SIM card is in the iPhone....

hoping that i can somehow use iOS's TFA but it seems very difficult.

thanks

 

[Rigby]

can you register more than 1 mobile number with two factor authentication?

Yes you can.

Also note that SMS is only one of two methods Apple can use to deliver codes to you. Besides SMS, it also can push a message via push notification to your iOS devices. For that you need only IP connectivity (i.e. it works over cellular data or Wifi, regardless which SIM you have in the phone).

does apple SMS its 4 digit passcode to all of the numbers associated with TFA, or just a primary one, or, just the last associated IMEI number that it has registered. or what?

You can select if it should be sent to one of your phone numbers via SMS or pushed to one of the trusted iOS devices that you previously registered.

also, apple says you need two of the following: password, the passcode SMSed to your mobile, or, the recovery key
but i read that the recovery key itself is a one time use recovery key (which seems impossible overkill but..) is this true? once used you need to get a new recovery key?

No.

if apple could somehow allow a hardware keychain type of TFA device then I could use TFA but I do not hear anything about that. and kind of 20 year ago tech anyway at that.

I would like them to support offline code generators such as Google Authenticator.