This paper presents a highly efficient multimode multiplier supporting prime field, namely, polynomial field, and matrix-vector multiplications based on an asymmetric word-based Montgomery multiplication (MM) algorithm. The proposed multimode 128 ?? 32 b multiplier provides throughput rates of 441 and 511 Mb/s for 256-b operands over GF(P) and GF(2n) at a clock rate of 100 MHz, respectively. With 21 930 additional gates for Advanced Encryption Standard (AES), the multiplier is extended to provide 1.28-, 1.06-, and 0.91-Gb/s throughput rates for 128-, 192-, and 256-b keys, respectively. The comparison result shows that the proposed integration architecture outperforms others in terms of performance and efficiency for both AES and MM that is essential in most public-key cryptosystems.