docs: public static BigInteger fromUnsignedByteArray(byte[] buf, int off, int length) {
  		byte[] mag = buf;
  		if (off != 0 || length != buf.length) {
  			mag = new byte[length];
  			System.arraycopy(buf, off, mag, 0, length);
  		}
  		return new BigInteger(1, mag);
  	}