The development of electronic signature in mobile devices is an essential issue for the advance and expansion of the mobile electronic commerce since it provides security and trust in the system. E-signatures provide security for the transactions with authenticity and integrity characteristics that make non-repudiation of the transactions possible.
In recent years, different technologies and infrastructures have been developed with the aim of implementing mobile signature processes. Some are based on the SIM card. Others work over the middleware of the mobile device and cryptographic providers. Finally, there are already some frameworks which are independent of specific mobile device technologies and make mobile signatures available to application providers. Therefore, there is a great range of possibilities. In this paper we review the different solutions to date to provide electronic signature in mobile devices (SMS signature, SATK, WIM, USAT-i, SATSA, Mobile signature service, etc). We will comment on the most important goals of each solution and analyse the advantages and disadvantages. From this analysis we will obtain a global view of the current and future tendencies of mobile signature and thus help to provide mobile signature solutions.
Key words: electronic signature, non repudiation, qualified signature, mobile signature, SIM card, Java ME, signature services, mobile devices, mobile commerce
Nowadays, the use of mobile handsets is widespread. In fact, according to some information provided by operators or organizations such as the ITU , mobile handsets have reached a significant penetration rate in many countries such as Luxemburg (164%), Italy (128%), Hong Kong (117%), Spain (109%), Chile (74%), Argentina (64%), and so on. That is, in many countries, almost everybody has a mobile handset (mobile phones, Personal Digital Assistants (PDA)?). This is due to the fact that these devices growth continually incorporate new advanced features related to communication and entertainment, for example, downloading of information, e-mail, instant messaging, video telephony, etc. Furthermore, during these last years, the computation and storage capabilities offered by these handsets have been improved considerably in order to provide these advanced features. Thus, as a consequence of its growth and to these advanced features, today the development of new services for these mobile devices constitutes one of the most important business markets because any service developed could, potentially, be offered to any person in the world.
At the same time, the mobile network infrastructure has been improved and, along with GSM (first generation in mobile technology -1G-), other technologies such as CDMA and W-CDMA (UTMS) have appeared. They constitute what is known as the third generation technology or 3G. These new technologies allow the simultaneous transmission of both voice data and non-voice data up to 2 Mbps. Currently, according to the ITU report , there are already 61.5 million subscribers worldwide with at least 256 kbps.
The improvement in both mobile devices and network capabilities leads us to think about the development of the advanced services that we have mentioned above: e-mail, instant messaging, video telephony, and so on. Thus, our mobile devices mean that we are able to be "always on" everywhere. Needless to say, one of the fields that can take advantage of these features is electronic commerce, which in this mobile scenario, has been named mobile commerce. The aim of mobile commerce is to allow users to do business and commerce from their mobile phones, for example, payments (named m-payments , ), location-based services , banking transactions, and so on. Basically, m-commerce consists of developing new applications and many of the services already offered in the electronic commerce, but now, taking advantage of the mobility features that the user has with their mobile handsets. …