It's from a programming language. "%' here is a modulo operation.
(a * 2^32 + b) % c = (((a % c) * (2^32 % c)) + b) % c
It's from a programming language. "%' here is a modulo operation.
(a * 2^32 + b) % c = (((a % c) * (2^32 % c)) + b) % c
In general, if you have two integers
a = j + kc
b = l + mc
Then
ab % c
= (j+kc)(l+mc) % c
= (jl + jmc + lkc + kmc^2) % c
= jl
= (a % c)(b % c)