A Practical Approach to a Secure E-Will System in the R.O.C.

Chien et al. (2009) proposed an e-will system on the Internet using an identity-based cryptosystem. They claimed that their e-will system was secure enough to be used in practice since their system conforms to R.O.C. (Taiwan) Civil Law. However, we found several problems of Chien et al.´s scheme. First, the Trust Authority knows or can easily compute the user´s private key. Therefore, it does not provide the non-repudiation property and it does not conform to the Electronic Signatures Act and the relevant regulations in the R.O.C. (Taiwan) government. Second, their scheme does not provide any long-term validation method of digital signatures. Therefore, we may fail to check the validity of the testator´s will after death. To solve these problems, we propose a novel e-will system based on Government Public Key Infrastructure (GPKI) that can be used in practice.