SMS security question.

Projects General Guidance
1

Hi,

I want to build a device that I can configure via SMS messages. I'd like the device to prioritize the messages it receives based on the phone number the message comes from. Or in other words the device needs to accept and obey messages from my phone, but ignore messages from other phone numbers.

When I receive and process an SMS message, I also get the phone number it's come from, what I want to know is how secure is the number? is it possible to spoof or fake it? I know that sometimes I process a message with "AT+CMGR", and instead of getting a numeric number it just says "TESCOS" or "ORANGE" is it possible for someone to generate and send and SMS and make it look like it's come from another number? I know that it's very easy to make an email appear to come from another address, can the same be done with SMSs?

If the 'from number' can be spoofed, then I'll need to somehow encrypt or encode the text message and base my security on the quality of the encoding, but this is going to be a lot harder.

Cheers

2

Aparently it can be spoofed.
http://fogmo.com/

Perhaps one time password system would be acceptable?

3

Aparently it can be spoofed.

bugger!

Perhaps one time password system would be acceptable?

Maybe, but I'm thinking it's a bit over the top for my needs. Maybe I'll just require that all valid messages include a known password- much easier than a OTP or encrypting the whole message.

Cheers