See What You Sign: Secure Implementations of Digital Signatures

An expectation of a signature system is that a signatory cannot dispute a signature. Aiming at this, the following questions arise: Can documents in electronic commerce on the Internet become legally valid without the implementation of signature procedures on secure computers with trustworthy user input and output? Can systems which lack secure user input and output be manipulated in such a way that financial damage arises? How should the liability for signatures made with systems without secure user input and output be assigned? This contribution provides arguments in support of the necessity for computers with secure user input and output as prerequisites for the achievement of bindingness. It is discussed that an economic way to achieve this is the development of portable devices. It is also discussed how the distribution of such devices can take place.