powMod

fnBigInt powMod(BigInt base, BigInt exp, BigInt mod)

Computes modular exponentiation: base^exp mod mod.

Uses Montgomery multiplication for odd moduli and CRT decomposition for even moduli to achieve efficient computation.

Parameters

baseThe base value
expThe exponent (must be non-negative)
modThe modulus (must be positive)

Returns

base^exp mod mod

Throws

Exception if mod <= 0