derive function
Implementation
Set<Uint8List> derive(Uint8List parentKey, Uint8List parentChaincode, int i) {
// From the spec: Data = 0x00 || ser256(kpar) || ser32(i)
final data = Uint8List.fromList([0, ...parentKey, ...toBigEndianArray(i)]);
final hmacSha512 = Hmac(sha512, parentChaincode);
final h = hmacSha512.convert(data);
final slipSeed = Uint8List.fromList(h.bytes.sublist(0, 32));
final chainCode = Uint8List.fromList(h.bytes.sublist(32));
return {slipSeed, chainCode};
}