bits2int static method
RFC6979: ensure ECDSA msg is X bytes.
Implementation
static BigInt bits2int(Uint8List bytes) {
// RFC suggests optional truncating via bits2octets
final int delta = bytes.length * 8 - 256;
// FIPS 186-4 4.6 suggests the leftmost min(nBitLen, outLen) bits, which
final BigInt bigInt = bytesToBigInt(bytes);
// matches bits2int. bits2int can produce res>N.
return delta > 0 ? bigInt >> delta : bigInt;
}