kargaranamir/cispa-prof-pellegrino-challenge.ipynb

## cispa-prof-pellegrino-challenge.ipynb
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  "metadata": {
    "colab": {
      "name": "CISPA-Challenges.ipynb",
      "provenance": [],
      "collapsed_sections": [],
      "authorship_tag": "ABX9TyPMET+Cne/CUOLgQanzaTMW",
      "include_colab_link": true
    },
    "kernelspec": {
      "name": "python3",
      "display_name": "Python 3"
    },
    "language_info": {
      "name": "python"
    }
  },
  "cells": [
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "view-in-github",
        "colab_type": "text"
      },
      "source": [
        "<a href=\"https://colab.research.google.com/gist/kargaranamir/705e32e27bbd6393f330206bf7b76f73/cispa-prof-pellegrino-challenge.ipynb\" target=\"_parent\"><img src=\"https://colab.research.google.com/assets/colab-badge.svg\" alt=\"Open In Colab\"/></a>"
      ]
    },
    {
      "cell_type": "markdown",
      "source": [
        "## Challenge 1\n",
        "Base64 decode.\n"
      ],
      "metadata": {
        "id": "36UJkbyO1UGR"
      }
    },
    {
      "cell_type": "code",
      "source": [
        "import base64"
      ],
      "metadata": {
        "id": "onHMS29RDkBU"
      },
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "code",
      "execution_count": null,
      "metadata": {
        "id": "2j40X-mIwCg_"
      },
      "outputs": [],
      "source": [
        "string_ch1 = \"\"\"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\"\"\""
      ]
    },
    {
      "cell_type": "code",
      "source": [
        "encode_bytes_ch1 = string_ch1.encode('ascii')\n",
        "message_bytes_ch1 = base64.b64decode(encode_bytes_ch1)\n",
        "message_ch1 = message_bytes_ch1.decode('ascii')\n",
        "message_ch1"
      ],
      "metadata": {
        "colab": {
          "base_uri": "https://localhost:8080/",
          "height": 71
        },
        "id": "a8igdym_zxa_",
        "outputId": "d8eabec3-ab14-4afa-d344-8e60fff36aba"
      },
      "execution_count": null,
      "outputs": [
        {
          "output_type": "execute_result",
          "data": {
            "text/plain": [
              "'Congratulation! You solved the challenge number 1. After your have submitted your application documents through the CISPA portal, send an email to pellegrino@cispa.de. The subject of the email must be the string token PIECE-OF-CAKE followed by your name. For example, if you name is John Doe, the subject will be the string \"PIECE-OF-CAKE John Doe\". Then, you must add to the... see the next challenge ;)'"
            ],
            "application/vnd.google.colaboratory.intrinsic+json": {
              "type": "string"
            }
          },
          "metadata": {},
          "execution_count": 143
        }
      ]
    },
    {
      "cell_type": "markdown",
      "source": [
        "## Challenge 2\n",
        "Combination of Base32 and Base64 decodes."
      ],
      "metadata": {
        "id": "oHo1UJoi09eX"
      }
    },
    {
      "cell_type": "code",
      "source": [
        "import base64"
      ],
      "metadata": {
        "id": "9RShT9fIDi8M"
      },
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "code",
      "source": [
        "string_ch2 = \"\"\"MRQXIYJ2ORSXQ5BPNB2G23B3MJQXGZJWGQWFAR3IGBRFO5ZLKBDWQ3CZK5ISWUCDHFXVUV2GNNIGU6DJMIZFENKQNJ4G6TKUGVCGCR2GONREOVTVLIZFKZ2NNJ3XMYKEIUVVASCBFNITEOLVLIZUU2DEJBLHGWKYKJYGEMRUNBEUM3DWMRJUE6TCGJ4DEWSXKFTWIR3INREUOTTPLFLXQ422K42W4WSTIJ2WIVZRNFNFQSLHJVUTIZ2UNU4TGTCDII2WEM2VM5RFQVT2MRBUE2C2I5IWOZCHNBWESSCOGBRW23DVLJ4UEMDCGJ2GYYTJIJGVEVSRORKXSMKTKQYE4TCJI5DDASKIKJXVUU2CNRRG2ULHMIZFSZ3EI5UGYSKIJYYVS3LQNRMTGULVKBBTS52QNJ3XMWLNHFVWKVBUHBGDE2BQMJLXOKY=\"\"\""
      ],
      "metadata": {
        "id": "sjFbiDfj1gEY"
      },
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "code",
      "source": [
        "string_ch2.isupper()"
      ],
      "metadata": {
        "colab": {
          "base_uri": "https://localhost:8080/"
        },
        "id": "ZD-8yfkB6H7f",
        "outputId": "863ea0ab-da7e-4b9e-96d2-df1a6f6de257"
      },
      "execution_count": null,
      "outputs": [
        {
          "output_type": "execute_result",
          "data": {
            "text/plain": [
              "True"
            ]
          },
          "metadata": {},
          "execution_count": 146
        }
      ]
    },
    {
      "cell_type": "code",
      "source": [
        "for i in ['O', '0', 'I', '1']:\n",
        "    if i in string_ch2:\n",
        "      print(f\"{i} is in string\")"
      ],
      "metadata": {
        "colab": {
          "base_uri": "https://localhost:8080/"
        },
        "id": "SoN_zOv_6Li0",
        "outputId": "79e884a5-4371-463e-d8e6-19a00a449337"
      },
      "execution_count": null,
      "outputs": [
        {
          "output_type": "stream",
          "name": "stdout",
          "text": [
            "O is in string\n",
            "I is in string\n"
          ]
        }
      ]
    },
    {
      "cell_type": "code",
      "source": [
        "encode_bytes_ch2 = string_ch2.encode(\"UTF-8\")\n",
        "message_bytes_ch2 = base64.b32decode(string_ch2)\n",
        "message_ch2 = message_bytes_ch2.decode('ascii')\n",
        "message_ch2"
      ],
      "metadata": {
        "colab": {
          "base_uri": "https://localhost:8080/",
          "height": 53
        },
        "id": "itFM3MZO1qny",
        "outputId": "bcd73cf4-64e7-46de-a09e-f1b27ee8abd7"
      },
      "execution_count": null,
      "outputs": [
        {
          "output_type": "execute_result",
          "data": {
            "text/plain": [
              "'data:text/html;base64,PGh0bWw+PGhlYWQ+PC9oZWFkPjxib2R5PjxoMT5DaGFsbGVuZ2UgMjwvaDE+PHA+Q29uZ3JhdHVsYXRpb24hIFlvdSBzb2x2ZWQgdGhlIGNoYWxsZW5nZSBudW1iZXIgMi4gTm93LCB5b3UgbXVzdCBhZGQgdGhlIHN0cmluZyB0b2tlbiBMRVQtUy1ST0NLIGF0IHRoZSBlbmQgb2YgdGhlIHN1YmplY3QuPC9wPjwvYm9keT48L2h0bWw+'"
            ],
            "application/vnd.google.colaboratory.intrinsic+json": {
              "type": "string"
            }
          },
          "metadata": {},
          "execution_count": 148
        }
      ]
    },
    {
      "cell_type": "code",
      "source": [
        "string_ch2p2 = message_ch2.split(',')[-1]"
      ],
      "metadata": {
        "id": "-33Ylw8P3_1n"
      },
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "code",
      "source": [
        "encode_bytes_ch2p2 = string_ch2p2.encode('ascii')\n",
        "message_bytes_ch2p2 = base64.b64decode(encode_bytes_ch2p2)\n",
        "message_ch2p2 = message_bytes_ch2p2.decode('ascii')\n",
        "message_ch2p2"
      ],
      "metadata": {
        "colab": {
          "base_uri": "https://localhost:8080/",
          "height": 53
        },
        "id": "8i5hIsl12V_Z",
        "outputId": "5200df86-5518-45a2-bd49-e4eda44a88e1"
      },
      "execution_count": null,
      "outputs": [
        {
          "output_type": "execute_result",
          "data": {
            "text/plain": [
              "'<html><head></head><body><h1>Challenge 2</h1><p>Congratulation! You solved the challenge number 2. Now, you must add the string token LET-S-ROCK at the end of the subject.</p></body></html>'"
            ],
            "application/vnd.google.colaboratory.intrinsic+json": {
              "type": "string"
            }
          },
          "metadata": {},
          "execution_count": 150
        }
      ]
    },
    {
      "cell_type": "markdown",
      "source": [
        "## Challenge 3\n",
        "Combination Base32 + Reverse + Cessar + Finding `CONGRATULATION!`"
      ],
      "metadata": {
        "id": "WeH3cohJ2WSz"
      }
    },
    {
      "cell_type": "code",
      "source": [
        "import base64"
      ],
      "metadata": {
        "id": "iSNbLfmcDgaU"
      },
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "code",
      "source": [
        "string_ch3 = \"\"\"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==\"\"\""
      ],
      "metadata": {
        "id": "9BFm-pi94iu0"
      },
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "code",
      "source": [
        "string_ch3.isupper()"
      ],
      "metadata": {
        "colab": {
          "base_uri": "https://localhost:8080/"
        },
        "id": "g_DXNK_s5Zry",
        "outputId": "1ff2003c-241a-4a2b-f042-8ec933fe3b8f"
      },
      "execution_count": null,
      "outputs": [
        {
          "output_type": "execute_result",
          "data": {
            "text/plain": [
              "True"
            ]
          },
          "metadata": {},
          "execution_count": 153
        }
      ]
    },
    {
      "cell_type": "code",
      "source": [
        "for i in ['O', '0', 'I', '1']:\n",
        "    if i in string_ch3:\n",
        "      print(f\"{i} is in string\")"
      ],
      "metadata": {
        "colab": {
          "base_uri": "https://localhost:8080/"
        },
        "id": "knCj5TZs5axP",
        "outputId": "82759249-65ea-495a-ccb2-1520527b8663"
      },
      "execution_count": null,
      "outputs": [
        {
          "output_type": "stream",
          "name": "stdout",
          "text": [
            "O is in string\n",
            "I is in string\n"
          ]
        }
      ]
    },
    {
      "cell_type": "code",
      "source": [
        "# Base 32 Decode\n",
        "encode_bytes_ch3 = string_ch3.encode(\"UTF-8\")\n",
        "message_bytes_ch3 = base64.b32decode(encode_bytes_ch3)\n",
        "message_ch3 = message_bytes_ch3.decode('ascii')\n",
        "message_ch3"
      ],
      "metadata": {
        "colab": {
          "base_uri": "https://localhost:8080/",
          "height": 89
        },
        "id": "blSl8PTR6voA",
        "outputId": "e30bb2c2-2b25-4c36-cc28-f30155669eaf"
      },
      "execution_count": null,
      "outputs": [
        {
          "output_type": "execute_result",
          "data": {
            "text/plain": [
              "'.fgavbc ba av fgyhfre tavgnruP .ghcghb qenqangf rug av abvghybf rug aehgre bg qrgprckr fv gv qan ,lc.abvghybf_3rtaryynup abuglc ,.r.v ,)UFNO( ravy qanzzbp nvi qrghprkr ro yyvj gcvepf ruG .qrqbp-qenu ro anp tavegf ghcav qrqbpar ruG .)rtnffrz fvug ,.r.v( abvghybf rug arrepf ab gavec yyvj gcvepf ruG .3# rtaryynup sb arxbg tavegf rug rqbprq bg zugvebtyn rug fgarzryczv gcvepf ruG .lc.abvghybf_3rtaryynup qryynp ryvs gcvepf abuglC n yvnzr rug bg upnggn rfnryC .3 erozha rtaryynup rug qriybf hbL !abvgnyhgnetabP'"
            ],
            "application/vnd.google.colaboratory.intrinsic+json": {
              "type": "string"
            }
          },
          "metadata": {},
          "execution_count": 155
        }
      ]
    },
    {
      "cell_type": "code",
      "source": [
        "# Mirror\n",
        "message_ch3p2 = message_ch3[::-1]\n",
        "message_ch3p2"
      ],
      "metadata": {
        "colab": {
          "base_uri": "https://localhost:8080/",
          "height": 89
        },
        "id": "2yU--nEa7-SF",
        "outputId": "24f00f41-a5f9-4d51-9f13-0e9cb7c45eed"
      },
      "execution_count": null,
      "outputs": [
        {
          "output_type": "execute_result",
          "data": {
            "text/plain": [
              "'Pbatenghyngvba! Lbh fbyirq gur punyyratr ahzore 3. Cyrnfr nggnpu gb gur rznvy n Clguba fpevcg svyr pnyyrq punyyratr3_fbyhgvba.cl. Gur fpevcg vzcyrzragf gur nytbevguz gb qrpbqr gur fgevat gbxra bs punyyratr #3. Gur fpevcg jvyy cevag ba fperra gur fbyhgvba (v.r., guvf zrffntr). Gur rapbqrq vachg fgevat pna or uneq-pbqrq. Gur fpevcg jvyy or rkrphgrq ivn pbzznaq yvar (ONFU), v.r., clguba punyyratr3_fbyhgvba.cl, naq vg vf rkcrpgrq gb erghea gur fbyhgvba va gur fgnaqneq bhgchg. Purngvat erfhygf va ab cbvagf.'"
            ],
            "application/vnd.google.colaboratory.intrinsic+json": {
              "type": "string"
            }
          },
          "metadata": {},
          "execution_count": 158
        }
      ]
    },
    {
      "cell_type": "code",
      "source": [
        "# define alphabet \n",
        "l_alphabet = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ' #large case\n",
        "s_alphabet = l_alphabet.lower() #lower case\n",
        "\n",
        "length = len(l_alphabet) # len of alphabet\n",
        "\n",
        "\n",
        "# iterate on alphabet key possibles, i.e., 0 to 26 (26 is not included)\n",
        "for key in range(0, length):\n",
        "    decrypted_massage_ch3p3 = \"\"\n",
        "\n",
        "    # iterate on encrypted massage\n",
        "    for s in message_ch3p2:\n",
        "        # find out which alphabet it uses. switch to that.\n",
        "        alphabet = \"\"\n",
        "        num = -1\n",
        "        # find the appropiate alphabet\n",
        "        num_l = l_alphabet.find(s) \n",
        "        num_s = s_alphabet.find(s)\n",
        "\n",
        "        # override the apptpiate alphabet variables \n",
        "        if num_l != -1:\n",
        "            alphabet = l_alphabet\n",
        "            num = num_l\n",
        "        elif num_s != -1:\n",
        "            alphabet = s_alphabet\n",
        "            num = num_s\n",
        "\n",
        "        # do the cessar\n",
        "        if s in alphabet:\n",
        "            num = num - key\n",
        "            if num < 0:\n",
        "                num = num + length\n",
        "            decrypted_massage_ch3p3 = decrypted_massage_ch3p3 + alphabet[num]\n",
        "        # if the symbol is not in alphabet just leave it unchanged.\n",
        "        else:\n",
        "            decrypted_massage_ch3p3 = decrypted_massage_ch3p3 + s\n",
        "\n",
        "    # check if the CONGRATULATION! or any other type of it (upper, lower) is in the result.\n",
        "    if 'CONGRATULATION!' in decrypted_massage_ch3p3.upper():\n",
        "        print(decrypted_massage_ch3p3)"
      ],
      "metadata": {
        "colab": {
          "base_uri": "https://localhost:8080/"
        },
        "id": "Asbp2Rs97nRP",
        "outputId": "e878282f-bfe2-48b4-9d61-d38f4c9e413d"
      },
      "execution_count": null,
      "outputs": [
        {
          "output_type": "stream",
          "name": "stdout",
          "text": [
            "Congratulation! You solved the challenge number 3. Please attach to the email a Python script file called challenge3_solution.py. The script implements the algorithm to decode the string token of challenge #3. The script will print on screen the solution (i.e., this message). The encoded input string can be hard-coded. The script will be executed via command line (BASH), i.e., python challenge3_solution.py, and it is expected to return the solution in the standard output. Cheating results in no points.\n"
          ]
        }
      ]
    }
  ]
}

## info.md

      
    Raw
  

              info.md
            
          
    Prof. Pellegrino has dropped his challenge on the website and added another. So I think it's okay to publicize this solution.
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	"name": "CISPA-Challenges.ipynb",
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	"cell_type": "markdown",
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	"id": "view-in-github",
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	"<a href=\"https://colab.research.google.com/gist/kargaranamir/705e32e27bbd6393f330206bf7b76f73/cispa-prof-pellegrino-challenge.ipynb\" target=\"_parent\"><img src=\"https://colab.research.google.com/assets/colab-badge.svg\" alt=\"Open In Colab\"/></a>"
	]
	},
	{
	"cell_type": "markdown",
	"source": [
	"## Challenge 1\n",
	"Base64 decode.\n"
	],
	"metadata": {
	"id": "36UJkbyO1UGR"
	}
	},
	{
	"cell_type": "code",
	"source": [
	"import base64"
	],
	"metadata": {
	"id": "onHMS29RDkBU"
	},
	"execution_count": null,
	"outputs": []
	},
	{
	"cell_type": "code",
	"execution_count": null,
	"metadata": {
	"id": "2j40X-mIwCg_"
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	"outputs": [],
	"source": [
	"string_ch1 = \"\"\"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\"\"\""
	]
	},
	{
	"cell_type": "code",
	"source": [
	"encode_bytes_ch1 = string_ch1.encode('ascii')\n",
	"message_bytes_ch1 = base64.b64decode(encode_bytes_ch1)\n",
	"message_ch1 = message_bytes_ch1.decode('ascii')\n",
	"message_ch1"
	],
	"metadata": {
	"colab": {
	"base_uri": "https://localhost:8080/",
	"height": 71
	},
	"id": "a8igdym_zxa_",
	"outputId": "d8eabec3-ab14-4afa-d344-8e60fff36aba"
	},
	"execution_count": null,
	"outputs": [
	{
	"output_type": "execute_result",
	"data": {
	"text/plain": [
	"'Congratulation! You solved the challenge number 1. After your have submitted your application documents through the CISPA portal, send an email to pellegrino@cispa.de. The subject of the email must be the string token PIECE-OF-CAKE followed by your name. For example, if you name is John Doe, the subject will be the string \"PIECE-OF-CAKE John Doe\". Then, you must add to the... see the next challenge ;)'"
	],
	"application/vnd.google.colaboratory.intrinsic+json": {
	"type": "string"
	}
	},
	"metadata": {},
	"execution_count": 143
	}
	]
	},
	{
	"cell_type": "markdown",
	"source": [
	"## Challenge 2\n",
	"Combination of Base32 and Base64 decodes."
	],
	"metadata": {
	"id": "oHo1UJoi09eX"
	}
	},
	{
	"cell_type": "code",
	"source": [
	"import base64"
	],
	"metadata": {
	"id": "9RShT9fIDi8M"
	},
	"execution_count": null,
	"outputs": []
	},
	{
	"cell_type": "code",
	"source": [
	"string_ch2 = \"\"\"MRQXIYJ2ORSXQ5BPNB2G23B3MJQXGZJWGQWFAR3IGBRFO5ZLKBDWQ3CZK5ISWUCDHFXVUV2GNNIGU6DJMIZFENKQNJ4G6TKUGVCGCR2GONREOVTVLIZFKZ2NNJ3XMYKEIUVVASCBFNITEOLVLIZUU2DEJBLHGWKYKJYGEMRUNBEUM3DWMRJUE6TCGJ4DEWSXKFTWIR3INREUOTTPLFLXQ422K42W4WSTIJ2WIVZRNFNFQSLHJVUTIZ2UNU4TGTCDII2WEM2VM5RFQVT2MRBUE2C2I5IWOZCHNBWESSCOGBRW23DVLJ4UEMDCGJ2GYYTJIJGVEVSRORKXSMKTKQYE4TCJI5DDASKIKJXVUU2CNRRG2ULHMIZFSZ3EI5UGYSKIJYYVS3LQNRMTGULVKBBTS52QNJ3XMWLNHFVWKVBUHBGDE2BQMJLXOKY=\"\"\""
	],
	"metadata": {
	"id": "sjFbiDfj1gEY"
	},
	"execution_count": null,
	"outputs": []
	},
	{
	"cell_type": "code",
	"source": [
	"string_ch2.isupper()"
	],
	"metadata": {
	"colab": {
	"base_uri": "https://localhost:8080/"
	},
	"id": "ZD-8yfkB6H7f",
	"outputId": "863ea0ab-da7e-4b9e-96d2-df1a6f6de257"
	},
	"execution_count": null,
	"outputs": [
	{
	"output_type": "execute_result",
	"data": {
	"text/plain": [
	"True"
	]
	},
	"metadata": {},
	"execution_count": 146
	}
	]
	},
	{
	"cell_type": "code",
	"source": [
	"for i in ['O', '0', 'I', '1']:\n",
	" if i in string_ch2:\n",
	" print(f\"{i} is in string\")"
	],
	"metadata": {
	"colab": {
	"base_uri": "https://localhost:8080/"
	},
	"id": "SoN_zOv_6Li0",
	"outputId": "79e884a5-4371-463e-d8e6-19a00a449337"
	},
	"execution_count": null,
	"outputs": [
	{
	"output_type": "stream",
	"name": "stdout",
	"text": [
	"O is in string\n",
	"I is in string\n"
	]
	}
	]
	},
	{
	"cell_type": "code",
	"source": [
	"encode_bytes_ch2 = string_ch2.encode(\"UTF-8\")\n",
	"message_bytes_ch2 = base64.b32decode(string_ch2)\n",
	"message_ch2 = message_bytes_ch2.decode('ascii')\n",
	"message_ch2"
	],
	"metadata": {
	"colab": {
	"base_uri": "https://localhost:8080/",
	"height": 53
	},
	"id": "itFM3MZO1qny",
	"outputId": "bcd73cf4-64e7-46de-a09e-f1b27ee8abd7"
	},
	"execution_count": null,
	"outputs": [
	{
	"output_type": "execute_result",
	"data": {
	"text/plain": [
	"'data:text/html;base64,PGh0bWw+PGhlYWQ+PC9oZWFkPjxib2R5PjxoMT5DaGFsbGVuZ2UgMjwvaDE+PHA+Q29uZ3JhdHVsYXRpb24hIFlvdSBzb2x2ZWQgdGhlIGNoYWxsZW5nZSBudW1iZXIgMi4gTm93LCB5b3UgbXVzdCBhZGQgdGhlIHN0cmluZyB0b2tlbiBMRVQtUy1ST0NLIGF0IHRoZSBlbmQgb2YgdGhlIHN1YmplY3QuPC9wPjwvYm9keT48L2h0bWw+'"
	],
	"application/vnd.google.colaboratory.intrinsic+json": {
	"type": "string"
	}
	},
	"metadata": {},
	"execution_count": 148
	}
	]
	},
	{
	"cell_type": "code",
	"source": [
	"string_ch2p2 = message_ch2.split(',')[-1]"
	],
	"metadata": {
	"id": "-33Ylw8P3_1n"
	},
	"execution_count": null,
	"outputs": []
	},
	{
	"cell_type": "code",
	"source": [
	"encode_bytes_ch2p2 = string_ch2p2.encode('ascii')\n",
	"message_bytes_ch2p2 = base64.b64decode(encode_bytes_ch2p2)\n",
	"message_ch2p2 = message_bytes_ch2p2.decode('ascii')\n",
	"message_ch2p2"
	],
	"metadata": {
	"colab": {
	"base_uri": "https://localhost:8080/",
	"height": 53
	},
	"id": "8i5hIsl12V_Z",
	"outputId": "5200df86-5518-45a2-bd49-e4eda44a88e1"
	},
	"execution_count": null,
	"outputs": [
	{
	"output_type": "execute_result",
	"data": {
	"text/plain": [
	"'<html><head></head><body><h1>Challenge 2</h1><p>Congratulation! You solved the challenge number 2. Now, you must add the string token LET-S-ROCK at the end of the subject.</p></body></html>'"
	],
	"application/vnd.google.colaboratory.intrinsic+json": {
	"type": "string"
	}
	},
	"metadata": {},
	"execution_count": 150
	}
	]
	},
	{
	"cell_type": "markdown",
	"source": [
	"## Challenge 3\n",
	"Combination Base32 + Reverse + Cessar + Finding `CONGRATULATION!`"
	],
	"metadata": {
	"id": "WeH3cohJ2WSz"
	}
	},
	{
	"cell_type": "code",
	"source": [
	"import base64"
	],
	"metadata": {
	"id": "iSNbLfmcDgaU"
	},
	"execution_count": null,
	"outputs": []
	},
	{
	"cell_type": "code",
	"source": [
	"string_ch3 = \"\"\"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==\"\"\""
	],
	"metadata": {
	"id": "9BFm-pi94iu0"
	},
	"execution_count": null,
	"outputs": []
	},
	{
	"cell_type": "code",
	"source": [
	"string_ch3.isupper()"
	],
	"metadata": {
	"colab": {
	"base_uri": "https://localhost:8080/"
	},
	"id": "g_DXNK_s5Zry",
	"outputId": "1ff2003c-241a-4a2b-f042-8ec933fe3b8f"
	},
	"execution_count": null,
	"outputs": [
	{
	"output_type": "execute_result",
	"data": {
	"text/plain": [
	"True"
	]
	},
	"metadata": {},
	"execution_count": 153
	}
	]
	},
	{
	"cell_type": "code",
	"source": [
	"for i in ['O', '0', 'I', '1']:\n",
	" if i in string_ch3:\n",
	" print(f\"{i} is in string\")"
	],
	"metadata": {
	"colab": {
	"base_uri": "https://localhost:8080/"
	},
	"id": "knCj5TZs5axP",
	"outputId": "82759249-65ea-495a-ccb2-1520527b8663"
	},
	"execution_count": null,
	"outputs": [
	{
	"output_type": "stream",
	"name": "stdout",
	"text": [
	"O is in string\n",
	"I is in string\n"
	]
	}
	]
	},
	{
	"cell_type": "code",
	"source": [
	"# Base 32 Decode\n",
	"encode_bytes_ch3 = string_ch3.encode(\"UTF-8\")\n",
	"message_bytes_ch3 = base64.b32decode(encode_bytes_ch3)\n",
	"message_ch3 = message_bytes_ch3.decode('ascii')\n",
	"message_ch3"
	],
	"metadata": {
	"colab": {
	"base_uri": "https://localhost:8080/",
	"height": 89
	},
	"id": "blSl8PTR6voA",
	"outputId": "e30bb2c2-2b25-4c36-cc28-f30155669eaf"
	},
	"execution_count": null,
	"outputs": [
	{
	"output_type": "execute_result",
	"data": {
	"text/plain": [
	"'.fgavbc ba av fgyhfre tavgnruP .ghcghb qenqangf rug av abvghybf rug aehgre bg qrgprckr fv gv qan ,lc.abvghybf_3rtaryynup abuglc ,.r.v ,)UFNO( ravy qanzzbp nvi qrghprkr ro yyvj gcvepf ruG .qrqbp-qenu ro anp tavegf ghcav qrqbpar ruG .)rtnffrz fvug ,.r.v( abvghybf rug arrepf ab gavec yyvj gcvepf ruG .3# rtaryynup sb arxbg tavegf rug rqbprq bg zugvebtyn rug fgarzryczv gcvepf ruG .lc.abvghybf_3rtaryynup qryynp ryvs gcvepf abuglC n yvnzr rug bg upnggn rfnryC .3 erozha rtaryynup rug qriybf hbL !abvgnyhgnetabP'"
	],
	"application/vnd.google.colaboratory.intrinsic+json": {
	"type": "string"
	}
	},
	"metadata": {},
	"execution_count": 155
	}
	]
	},
	{
	"cell_type": "code",
	"source": [
	"# Mirror\n",
	"message_ch3p2 = message_ch3[::-1]\n",
	"message_ch3p2"
	],
	"metadata": {
	"colab": {
	"base_uri": "https://localhost:8080/",
	"height": 89
	},
	"id": "2yU--nEa7-SF",
	"outputId": "24f00f41-a5f9-4d51-9f13-0e9cb7c45eed"
	},
	"execution_count": null,
	"outputs": [
	{
	"output_type": "execute_result",
	"data": {
	"text/plain": [
	"'Pbatenghyngvba! Lbh fbyirq gur punyyratr ahzore 3. Cyrnfr nggnpu gb gur rznvy n Clguba fpevcg svyr pnyyrq punyyratr3_fbyhgvba.cl. Gur fpevcg vzcyrzragf gur nytbevguz gb qrpbqr gur fgevat gbxra bs punyyratr #3. Gur fpevcg jvyy cevag ba fperra gur fbyhgvba (v.r., guvf zrffntr). Gur rapbqrq vachg fgevat pna or uneq-pbqrq. Gur fpevcg jvyy or rkrphgrq ivn pbzznaq yvar (ONFU), v.r., clguba punyyratr3_fbyhgvba.cl, naq vg vf rkcrpgrq gb erghea gur fbyhgvba va gur fgnaqneq bhgchg. Purngvat erfhygf va ab cbvagf.'"
	],
	"application/vnd.google.colaboratory.intrinsic+json": {
	"type": "string"
	}
	},
	"metadata": {},
	"execution_count": 158
	}
	]
	},
	{
	"cell_type": "code",
	"source": [
	"# define alphabet \n",
	"l_alphabet = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ' #large case\n",
	"s_alphabet = l_alphabet.lower() #lower case\n",
	"\n",
	"length = len(l_alphabet) # len of alphabet\n",
	"\n",
	"\n",
	"# iterate on alphabet key possibles, i.e., 0 to 26 (26 is not included)\n",
	"for key in range(0, length):\n",
	" decrypted_massage_ch3p3 = \"\"\n",
	"\n",
	" # iterate on encrypted massage\n",
	" for s in message_ch3p2:\n",
	" # find out which alphabet it uses. switch to that.\n",
	" alphabet = \"\"\n",
	" num = -1\n",
	" # find the appropiate alphabet\n",
	" num_l = l_alphabet.find(s) \n",
	" num_s = s_alphabet.find(s)\n",
	"\n",
	" # override the apptpiate alphabet variables \n",
	" if num_l != -1:\n",
	" alphabet = l_alphabet\n",
	" num = num_l\n",
	" elif num_s != -1:\n",
	" alphabet = s_alphabet\n",
	" num = num_s\n",
	"\n",
	" # do the cessar\n",
	" if s in alphabet:\n",
	" num = num - key\n",
	" if num < 0:\n",
	" num = num + length\n",
	" decrypted_massage_ch3p3 = decrypted_massage_ch3p3 + alphabet[num]\n",
	" # if the symbol is not in alphabet just leave it unchanged.\n",
	" else:\n",
	" decrypted_massage_ch3p3 = decrypted_massage_ch3p3 + s\n",
	"\n",
	" # check if the CONGRATULATION! or any other type of it (upper, lower) is in the result.\n",
	" if 'CONGRATULATION!' in decrypted_massage_ch3p3.upper():\n",
	" print(decrypted_massage_ch3p3)"
	],
	"metadata": {
	"colab": {
	"base_uri": "https://localhost:8080/"
	},
	"id": "Asbp2Rs97nRP",
	"outputId": "e878282f-bfe2-48b4-9d61-d38f4c9e413d"
	},
	"execution_count": null,
	"outputs": [
	{
	"output_type": "stream",
	"name": "stdout",
	"text": [
	"Congratulation! You solved the challenge number 3. Please attach to the email a Python script file called challenge3_solution.py. The script implements the algorithm to decode the string token of challenge #3. The script will print on screen the solution (i.e., this message). The encoded input string can be hard-coded. The script will be executed via command line (BASH), i.e., python challenge3_solution.py, and it is expected to return the solution in the standard output. Cheating results in no points.\n"
	]
	}
	]
	}
	]
	}