The Montgomery inverse and its applications
Burton S. Kaliski · IEEE Transactions on Computers · 1995
The Montgomery inverse of b module a is b/sup -1/2/sup n/ mod a, where n is the number of bits in a. The right-shifting binary algorithm for modular inversion is shown naturally to compute the new inverse in fewer operations than the ordinary modular inverse. The new inverse facilitates recent work by Koc on modular exponentiation and has other applications in cryptography.>