On Dec 14, 2007 8:04 AM, Torsten Schlabach <[EMAIL PROTECTED]> wrote: > There is for example somthing in Bluetooth called "SIM access profile" > which is a mean to share a SIM card over Bluetooth. This is used by some > built-in car phones (not to mix up with simple hands-free sets, which > just transmit the audio over the Bluetooth connection) which read the > SIM card of the mobile in your pocket when you enter the car. > > I was looking at implementing whatever mechanism where I could host a > SIM card that I legally own on a server and communicate with that SIM > card over whatever network connection (WiFi if available, maybe UMTS, > Bluetooth, ...).
If it can be done via SIM access profile, it could also be done on a server as you suggest. So the GSM module must provide some AT commands to access whatever you need in order to implement SIM access profile, right? They probably consider that as long as the card is "live" (actually connected to a card reader) and the exchange of information (challenge/response) is the same as it would be if the card were physically connected to the radio that is using it, then the security is preserved. The communications with the card are not secret, but the key which the card stores is the secret, and the communication stream does not reveal it. So why don't you investigate how to do that? First figure out how to implement SIM access profile (specs for that from the Bluetooth SIG would probably explain how.) Then you have code which would work just as well on a server that has a GSM module connected via serial line, and a Bluetooth dongle for the SIM access. (You can buy a GSM module from SparkFun for that, and probably connect it via one of those DLP-232 USB-to-serial cables.) Then, maybe figure out how to do the same communications with the SIM card, with a simple USB SIM card reader, so that the extra GSM module is not required (since it's only being used as a card reader, effectively). > But as I cannot hook the communication between the GSM modem and the SIM > card (which is some kind of serial line connection) I have no means of > doing that. Not directly with existing FIC hardware, but you could get out your spectrum analyzer and monitor the communications. But it's cryptography... it's not meant to be easy to crack. But if you only want to provide a "wireless extension cable" to the physical SIM, that's already sanctioned. Another idea would be to use a GSM module with an Asterisk server. Then you could use that virtual phone from anywhere that you have network access to reach the server. (But then you could also buy VOIP termination service, to virtualize it completely... so how is it better to use GSM?) If you wanted to use it remotely, without a pre-existing network connection, it's a chicken/egg problem... you need the network in order to access the SIM remotely, but you're not going to have GPRS until you access the SIM.
