Transaction Oriented Text Messaging with Trusted-SMS

The exponential growth of the Short Message Service(SMS) use has led this service to a widespread tool for social, marketing and advertising messaging. The mobile devices are quickly becoming Personal Trust Devices (PTD), embedding personal data, which allow sending/receiving private information from/to the PTD. This paper introduces our Trusted-SMS system, which allows users to exchange non-repudiable SMS´s, digitally signed with the Elliptic Curve Digital Signature Algorithm (ECDSA). This system can fit in many scenarios, such as commercial transaction, bureaucratic delegation etc.. In fact, the few bytes signature is embedded into a single SMS, leaving many bytes, depending on the choice of the elliptic curve, for the SMS payload.