Abstract.A new algorithm is proposed for the software implementation of modular multiplication, which uses pre-computations with a constant module. The developed modular multiplication algorithm provides high performance in comparison with the already known algorithms, and is oriented at the variable value of the module, especially with the software implementation on micro controllers and smart cards with a small number of bits.

Abstract.A new algorithm is proposed for the software implementation of modular multiplication, which uses pre-computations with a constant module. The developed modular multiplication algorithm provides high performance in comparison with the already known algorithms, and is oriented at the variable value of the module, especially with the software implementation on micro controllers and smart cards with a small number of bits.

Abstract. In this paper a new approach to increase the effectiveness of the errors detection using check sum during the data transmission based on the optimization of coding with special differential Boolean transformations is proposed. A method for obtaining such transformations are developed and examples of coding for check sum functions is given.