@Christoph-Hart I think I succeeded, thanks
const d = BigInt('0x' + dHex);
const n = BigInt('0x' + nHex);
const modulusBits = n.toString(2).length;
const modulusBytes = Math.ceil(modulusBits / 8);
const requiredHexLength = modulusBytes * 2;
const messageBuffer = Buffer.from(machineCode);
const reversedBuffer = Buffer.from(messageBuffer).reverse();
let value = BigInt('0x' + reversedBuffer.toString('hex'));
let result = 0n;
const modulus = n;
while (value > 0n) {
const remainder = value % modulus;
value = value / modulus;
const encryptedChunk = modExp(remainder, d, modulus);
result = result * modulus + encryptedChunk;
}
let hexStr = result.toString(16).padStart(requiredHexLength, '0');
const finalBuffer = Buffer.from(hexStr, 'hex');
return { activationCode: finalBuffer.toString('hex') };
function modExp(base, exp, mod) {
let result = 1n;
base = base % mod;
while (exp > 0n) {
if (exp & 1n)
result = (result * base) % mod;
exp = exp >> 1n;
base = (base * base) % mod;
}
return result;
}
