Realizing arbitrary-precision modular multiplication with a fixed-precision multiplier datapath

Within the context of cryptographic hardware, the term scalability refers to the ability to process operands of any size, regardless of the precision of the underlying data path or registers. In this paper we present a simple yet effective technique for increasing the scalability of a fixed-precision Montgomery multiplier. Our idea is to extend the datapath of a Montgomery multiplier in such a way that it can also perform an ordinary multiplication of two n-bit operands (without modular reduction), yielding a 2n-bit result. This conventional (nxn->2n)-bit multiplication is then used as a “sub-routine” to realize arbitrary-precision Montgomery multiplication according to standard software algorithms such as Coarsely Integrated Operand Scanning (CIOS). We show that performing a 2n-bit modular multiplication on an n-bit multiplier can be done in 5n clock cycles, whereby we assume that the n-bit modular multiplication takes n cycles. Extending a Montgomery multiplier for this extra functionality requires just some minor modifications of the datapath and entails a slight increase in silicon area

An FPGA Implementation of a Montgomery Multiplier Over GF(2^m)

This paper describes an efficient FPGA implementation for modular multiplication in the finite field GF(2^m) that is suitable for implementing Elliptic Curve Cryptosystems. We have developed a systolic array implementation of a~Montgomery modular multiplication. Our solution is efficient for large finite fields (m=160-193), that offer a high security level, and it can be scaled easily to larger values of m. The clock frequency of the implementation is independent of the field size. In contrast to earlier work, the design is not restricted to field representations using irreducible trinomials, all one polynomials or equally spaced polynomials

Parametric, Secure and Compact Implementation of RSA on FPGA

We present a fast, efficient, and parameterized modular multiplier and a secure exponentiation circuit especially intended for FPGAs on the low end of the price range. The design utilizes dedicated block multipliers as the main functional unit and Block-RAM as storage unit for the operands. The adopted design methodology allows adjusting the number of multipliers, the radix used in the multipliers, and number of words to meet the system requirements such as available resources, precision and timing constraints. The architecture, based on the Montgomery modular multiplication algorithm, utilizes a pipelining technique that allows concurrent operation of hardwired multipliers. Our design completes 1020-bit and 2040-bit modular multiplications in 7.62 μs and 27.0 μs, respectively. The multiplier uses a moderate amount of system resources while achieving the best area-time product in literature. 2040-bit modular exponentiation engine can easily fit into Xilinx Spartan-3E 500; moreover the exponentiation circuit withstands known side channel attacks

A high-speed integrated circuit with applications to RSA Cryptography

Merged with duplicate record 10026.1/833 on 01.02.2017 by CS (TIS)The rapid growth in the use of computers and networks in government, commercial and private communications systems has led to an increasing need for these systems to be secure against unauthorised access and eavesdropping. To this end, modern computer security systems employ public-key ciphers, of which probably the most well known is the RSA ciphersystem, to provide both secrecy and authentication facilities. The basic RSA cryptographic operation is a modular exponentiation where the modulus and exponent are integers typically greater than 500 bits long. Therefore, to obtain reasonable encryption rates using the RSA cipher requires that it be implemented in hardware. This thesis presents the design of a high-performance VLSI device, called the WHiSpER chip, that can perform the modular exponentiations required by the RSA cryptosystem for moduli and exponents up to 506 bits long. The design has an expected throughput in excess of 64kbit/s making it attractive for use both as a general RSA processor within the security function provider of a security system, and for direct use on moderate-speed public communication networks such as ISDN. The thesis investigates the low-level techniques used for implementing high-speed arithmetic hardware in general, and reviews the methods used by designers of existing modular multiplication/exponentiation circuits with respect to circuit speed and efficiency. A new modular multiplication algorithm, MMDDAMMM, based on Montgomery arithmetic, together with an efficient multiplier architecture, are proposed that remove the speed bottleneck of previous designs. Finally, the implementation of the new algorithm and architecture within the WHiSpER chip is detailed, along with a discussion of the application of the chip to ciphering and key generation

Arithmetic Operations in Multi-Valued Logic

This paper presents arithmetic operations like addition, subtraction and multiplications in Modulo-4 arithmetic, and also addition, multiplication in Galois field, using multi-valued logic (MVL). Quaternary to binary and binary to quaternary converters are designed using down literal circuits. Negation in modular arithmetic is designed with only one gate. Logic design of each operation is achieved by reducing the terms using Karnaugh diagrams, keeping minimum number of gates and depth of net in to consideration. Quaternary multiplier circuit is proposed to achieve required optimization. Simulation result of each operation is shown separately using Hspice.Comment: 12 Pages, VLSICS Journal 201

Low Power and Improved Speed Montgomery Multiplier using Universal Building Blocks

This paper describes the arithmetic blocks based on Montgomery Multiplier (MM), which reduces complexity, gives lower power dissipation and higher operating frequency. The main objective in designing these arithmetic blocks is to use modified full adder structure and carry save adder structure that can be implemented in algorithm based MM circuit. The conventional full adder design acts as a benchmark for comparison, the second is the modified Boolean equation for full adder and third design is the design of full adder consisting of two XOR gate and a 2-to-1 Multiplexer. Besides Universal gates such as NOR gate and NAND gate, full adder circuits are used to further improve the speed of the circuit. The MM circuit is evaluated based on different parameters such as operating frequency, power dissipation and area of occupancy in FPGA board. The schematic designs of the arithmetic components along with the MM architecture are constructed using Quartus II tool, while the simulation is done using Model sim for verification of circuit functionality which has shown improvement on the full adder design with two XOR gate and one 2-to-1 Multiplexer implementation in terms of power dissipation, operating frequency and area

Maximizing the Efficiency using Montgomery Multipliers on FPGA in RSA Cryptography for Wireless Sensor Networks

The architecture and modeling of RSA public key encryption/decryption systems are presented in this work. Two different architectures are proposed, mMMM42 (modified Montgomery Modular Multiplier 4 to 2 Carry Save Architecture) and RSACIPHER128 to check the suitability for implementation in Wireless Sensor Nodes to utilize the same in Wireless Sensor Networks. It can easily be fitting into systems that require different levels of security by changing the key size. The processing time is increased and space utilization is reduced in FPGA due to its reusability. VHDL code is synthesized and simulated using Xilinx-ISE for both the architectures. Architectures are compared in terms of area and time. It is verified that this architecture support for a key size of 128bits. The implementation of RSA encryption/decryption algorithm on FPGA using 128 bits data and key size with RSACIPHER128 gives good result with 50% less utilization of hardware. This design is also implemented for ASIC using Mentor Graphics

Modular Exponentiation on Reconfigurable Hardware

It is widely recognized that security issues will play a crucial role in the majority of future computer and communication systems. A central tool for achieving system security are cryptographic algorithms. For performance as well as for physical security reasons, it is often advantageous to realize cryptographic algorithms in hardware. In order to overcome the well-known drawback of reduced flexibility that is associated with traditional ASIC solutions, this contribution proposes arithmetic architectures which are optimized for modern field programmable gate arrays (FPGAs). The proposed architectures perform modular exponentiation with very long integers. This operation is at the heart of many practical public-key algorithms such as RSA and discrete logarithm schemes. We combine two versions of Montgomery modular multiplication algorithm with new systolic array designs which are well suited for FPGA realizations. The first one is based on a radix of two and is capable of processing a variable number of bits per array cell leading to a low cost design. The second design uses a radix of sixteen, resulting in a speed-up of a factor three at the cost of more used resources. The designs are flexible, allowing any choice of operand and modulus. Unlike previous approaches, we systematically implement and compare several versions of our new architecture for different bit lengths. We provide absolute area and timing measures for each architecture on Xilinx XC4000 series FPGAs. As a first practical result we show that it is possible to implement modular exponentiation at secure bit lengths on a single commercially available FPGA. Secondly we present faster processing times than previously reported. The Diffie-Hellman key exchange scheme with a modulus of 1024 bits and an exponent of 160 bits is computed in 1.9 ms. Our fastest design computes a 1024 bit RSA decryption in 3.1 ms when the Chinese remainder theorem is applied. These times are more than ten times faster than any reported software implementation. They also outperform most of the hardware-implementations presented in technical literature