| Abstract [eng] |
As mobile phones and technology advance new opportunities for implementation of elektronic money systems become possible. Electronic money is one of the latest methods for paying for goods and there are just a few implementations. In this work implementation of Stefan Brands electronic money model was performed. Stefan Brands protocol was implemented using Java langauge in standard computer and in mobile phone. Efficiency of these implementations was estimated and it was found that implementation on mobile phone is approximetly 100 times slower using Java ME platform. A library for for doing arithmetic operations like addition, subraction, modulus, modular exponentiation, right shift, etc. was implemented using smart card enviroment. As it is not possible to use cryptographic processor directly, RSA encryption scheme was used to perform modular exponention. Results of implementation speed were given and it was concluded that whole client side implementation using Java Card enviroment was two slow so mixed model was suggested. This work also consist of technical and software analysis needed to perform electronic money implementation. Also a brief review of cryptographic ant mathematic methods used in Stefan Brands digital cash system was performed. |
