Function mod_exp

tests/binary/rsa/src/main.rs:12–25

Modular exponentiation: (base^exp) % modulus

(mut base: u64, mut exp: u64, modulus: u64)

// Modular exponentiation: (base^exp) % modulus
fn mod_exp(mut base: u64, mut exp: u64, modulus: u64) -> u64 {
    let mut result = 1;
    base %= modulus;

    while exp > 0 {
        if exp % 2 == 1 {
            result = (result * base) % modulus;
        }
        exp >>= 1;
        base = (base * base) % modulus;
    }

    result
}

// Extended Euclidean Algorithm to find modular inverse
fn mod_inv(a: i64, m: i64) -> i64 {