Cryptographic algorithms are increasingly used in personal transaction through Internet network, smart card and telecommunication applications. Those algorithms are well known for their high complexity data computing. This paper focuses on Montgomery algorithm, which computes modular multiplication efficiently. This operation is the most time consuming part of public-key cryptosystems. A comparison among different implementations of the Montgomery algorithm in different architectures (GPP 1 , DSP, fine grain FPGA, coarse grain reconfigurable architecture [CGRA]) is presented. It is shown that coarse grain reconfigurable architecture might be good candidate to implement and to execute Montgomery multiplication. The paper also details the CGRA chosen to implement the referred algorithm.