Along with the rapid development in security technology, the efficient implementation of a large field-size elliptic curve cryptosystem (ECC) is becoming demanding in many critical applications as small-sized cryptosystems are gradually becoming obsolete. Based on this consideration, this paper proposes a series of novel coherent interdependence efforts to propose a novel implementation of ECC hardware cryptoprocessor: (i) We firstly propose a new Montgomery point multiplication (PM) algorithm to optimize and balance the signal flow and resource utilization efficiency; (ii) Then, we have efficiently constructed a new ECC processor over GF (2 m ) (with the support of a series of algorithm-architecture coimplementation techniques); (iii) Finally, we have given detailed comparison and performance analysis to show that the proposed cryptographic processor has superior performance than the competing designs, i.e., smaller area-delay product (ADP) than the competing designs. The proposed large field-size ECC processor (and the proposed design strategy) can be extended and applied in many security-demanding applications.INDEX TERMS Elliptic curve cryptography, FPGA, hardware design, large field-size, low-complexity, point multiplication.