feistel-py inconsistent number encryption

sample.ipynb

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     "text": [
      "Collecting feistel-py\n",
      "  Downloading feistel_py-0.2.0-py3-none-any.whl.metadata (9.2 kB)\n",
      "Collecting pycryptodome>=3.20.0 (from feistel-py)\n",
      "  Downloading pycryptodome-3.21.0-cp36-abi3-manylinux_2_17_x86_64.manylinux2014_x86_64.whl.metadata (3.4 kB)\n",
      "Collecting py-utls>=0.2.0 (from feistel-py)\n",
      "  Downloading py_utls-0.2.0-py3-none-any.whl.metadata (2.2 kB)\n",
      "Downloading feistel_py-0.2.0-py3-none-any.whl (14 kB)\n",
      "Downloading py_utls-0.2.0-py3-none-any.whl (3.6 kB)\n",
      "Downloading pycryptodome-3.21.0-cp36-abi3-manylinux_2_17_x86_64.manylinux2014_x86_64.whl (2.3 MB)\n",
      "\u001b[2K   \u001b[90m━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━\u001b[0m \u001b[32m2.3/2.3 MB\u001b[0m \u001b[31m5.9 MB/s\u001b[0m eta \u001b[36m0:00:00\u001b[0ma \u001b[36m0:00:01\u001b[0m\n",
      "\u001b[?25hInstalling collected packages: pycryptodome, py-utls, feistel-py\n",
      "Successfully installed feistel-py-0.2.0 py-utls-0.2.0 pycryptodome-3.21.0\n"
     ]
    }
   ],
   "source": [
    "! pip install feistel-py"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "id": "0c2cc26a-6f3a-4262-a856-c91b3c3fd7d2",
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "1403 22826 3451\n"
     ]
    }
   ],
   "source": [
    "from feistel import FPECipher, SHA_256\n",
    "\n",
    "cipher = FPECipher(SHA_256, \"some-32-byte-long-key-to-be-safe\", 128)\n",
    "\n",
    "number = 1403\n",
    "obfuscated = cipher.encrypt_number(number)\n",
    "deciphered = cipher.decrypt_number(obfuscated)\n",
    "print(number, obfuscated, deciphered)\n",
    "# 1403 22826 3451"
   ]
  }
 ],
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