private static EInteger FuzzInteger( EInteger ei, int fuzzes, RandomGenerator r) { byte[] bytes = ei.ToBytes(true); int bits = ei.GetUnsignedBitLength(); for (var i = 0; i < fuzzes; ++i) { int bit = r.UniformInt(bits); bytes[bit / 8] ^= (byte)(1 << (bit & 0x07)); } return EInteger.FromBytes(bytes, true); }