A High-Speed Elliptic Curve Cryptography Processor for Teleoperated Systems Security

Algorithm 4

Karatsuba–Ofman multiplication algorithm.

	Input: A: 256-bit integer, satisfy A = a1 × 2^128 + a0
	B: 256 bit integer, satisfy B = b1 × 2^128 + b0.
	Output: C: 512 bit product, satisfy C = A × B.
(1)	P00 = a0 × b0; asum = a0 + a1;
(2)	P11 = a1 × b1; bsum = b0 + b1;
(3)	Pss = asum × bsum, C = (P11, P00) – P00 × 2^128;
(4)	C = C – P11 × 2^128;
(5)	C = C + Pss × 2^128;
(6)	return C