1export function modPow(b, e, m) {
 2    let r = 1n;
 3    b = b % m;
 4    while (e > 0n) {
 5        if ((e & 1n) === 1n) {
 6            r = (r * b) % m;
 7        }
 8        e = e >> 1n;
 9        b = (b * b) % m;
10    }
11    return r;
12}
13
14export function bigIntToU8Array(bigint, padLength=0) {
15    let hex = bigint.toString(16);
16    if (padLength === 0) {
17        padLength = Math.ceil(hex.length / 2);
18    }
19    hex = hex.padStart(padLength * 2, '0');
20    const length = hex.length / 2;
21    const arr = new Uint8Array(length);
22    for (let i = 0; i < length; i++) {
23        arr[i] = parseInt(hex.slice(i * 2, i * 2 + 2), 16);
24    }
25    return arr;
26}
27
28export function u8ArrayToBigInt(arr) {
29    let hex = '0x';
30    for (let i = 0; i < arr.length; i++) {
31        hex += arr[i].toString(16).padStart(2, '0');
32    }
33    return BigInt(hex);
34}