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+{
+ "cells": [
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "# Message Encryption & Decryption\n",
+    "\n",
+    "## Yidi Chi\n",
+    "## POL-team, Ironhack, 22/10/2020\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "Encryption is the process of encoding information in such a way that only authorized parties can access it. It allows us to securely protect data which we don’t want just anyone to see or access.\n",
+    "\n",
+    "#### What is meant By Encryption?\n",
+    "\n",
+    "Encryption is a process which transforms the original information into an unrecognizable form. This new form of the message is entirely different from the original message.Encryption is usually done using key algorithms.\n",
+    "\n",
+    "#### What is meant by Decryption?\n",
+    "\n",
+    "Decryption is a process of converting encoded/encrypted data in a form that is readable and understood by a human or a computer. This method is performed by un-encrypting the text manually or by using keys used to encrypt the original data.\n",
+    "\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "#### About DEMO :\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "- First, create encrypt function which accepts the string I'm going to encrypt along with key as a 2nd argument with which we are going to do encryption.\n",
+    "\n",
+    "This function encrypt the string message based on the key you suggest.\n",
+    "\n",
+    "- Second create a decrypt function after the encrypt function which will then decode our encrypted message back to its original message.\n",
+    "\n",
+    "\n",
+    "\n"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 2,
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Enter your message:hello\n",
+      "Enter your key:4\n"
+     ]
+    }
+   ],
+   "source": [
+    "messages = input('Enter your message:')\n",
+    "\n",
+    "key = int(input('Enter your key:'))\n",
+    "\n",
+    "letters1 ='abcdefghijklmnopqrstuvwxyz'\n",
+    "letters2 =letters1.upper()\n",
+    "letters= letters1+letters2\n",
+    "\n",
+    "def encrypt(message, key):\n",
+    "    encrypted=''\n",
+    "    for i in message:\n",
+    "        text=letters.find(i)\n",
+    "        newtext=(text+key)%26\n",
+    "        encrypted+=letters[newtext]\n",
+    "    return encrypted\n",
+    "\n",
+    "\n",
+    "\n",
+    "def decrypt(message, key):\n",
+    "    decrypted=''\n",
+    "    for i in message:\n",
+    "        text1=letters.find(i)\n",
+    "        newtext1=(text1-key)%26\n",
+    "        decrypted+=letters[newtext1]\n",
+    "    return decrypted\n",
+    "\n",
+    "\n",
+    "message=messages\n",
+    "\n",
+    "\n"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 3,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "'lipps'"
+      ]
+     },
+     "execution_count": 3,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "\n",
+    "encrypt(message, key)\n",
+    "\n"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 4,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "#print(encrypt(message, key))"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 5,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "encrypted_message=encrypt(messages, key)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 6,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "'hello'"
+      ]
+     },
+     "execution_count": 6,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "decrypt(encrypted_message, key)\n",
+    "\n"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": []
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Python 3",
+   "language": "python",
+   "name": "python3"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 3
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython3",
+   "version": "3.7.6"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 4
+}