[hunt3r972]

This is a variant of the Cesar Code. It works the same way, but the coding step if made with a word instead of a uniq letter

Code:

#!/usr/bin/env python3.3 #RUN WITH python codevigenere.py #YOU CAN USE SPECIAL CHARS import sys choixmenu=raw_input("Do you want to crypt or decrypt ? type 1 to crypt or 2 to decrypt: ") while (choixmenu != "1") and (choixmenu != "2"): #On verifie que 1 ou 2 est demande sinon on demande a nouveau choixmenu=raw_input("You must type 1 or 2 ? type 1 to crypt or 2 to decrypt: ") if choixmenu == "1": #On veut encoder choixcle=raw_input("Type the word you want to use to crypt your message: ") choixcle=choixcle.upper() message=raw_input("Type your message: ") message=message.upper() #On passe le message en majuscule savecle=[] savemess=[] k=0 l=0 for i in choixcle: valchiffre1=ord(i) #On recupere la valeur ascii de chaque lettre #On initialiste le dictionnaire qui fait la correspondance valeure ascii->chiffre normal dichiffre = {65:0, 66:1, 67:2, 68:3, 69:4, 70:5, 71:6, 72:7, 73:8, 74:9, 75:10, 76:11, 77:12, 78:13, 79:14, 80:15, 81:16, 82:17, 83:18, 84:19, 85:20, 86:21, 87:22, 88:23, 89:24, 90:25} clechiffre=dichiffre[valchiffre1] savecle.append(clechiffre) for j in message: valchiffre2=ord(j) #On recupere la valeur ascii de chaque lettre if (valchiffre2 >= 65) and (valchiffre2 <= 90): #On initialiste le dictionnaire qui fait la correspondance valeure ascii->chiffre normal dichiffre = {65:0, 66:1, 67:2, 68:3, 69:4, 70:5, 71:6, 72:7, 73:8, 74:9, 75:10, 76:11, 77:12, 78:13, 79:14, 80:15, 81:16, 82:17, 83:18, 84:19, 85:20, 86:21, 87:22, 88:23, 89:24, 90:25} messagechiffre=dichiffre[valchiffre2] savemess.append(messagechiffre) else: messagechiffre=valchiffre2 savemess.append(messagechiffre) while k < len(message): x=savemess[k] if (x >= 32) and (x <= 64) or (x >= 91) and (x <= 96) or (x >= 123) and (x <= 126): convertion=x valascii=convertion else: if l == len(choixcle): l=0 y=savecle[l] l += 1 else: y=savecle[l] l += 1 convertion=(x+y)%26 #On initialiste le dictionnaire qui fait la correspondance valeure chiffre normal->ascii dicascii = {0:65, 1:66, 2:67, 3:68, 4:69, 5:70, 6:71, 7:72, 8:73, 9:74, 10:75, 11:76, 12:77, 13:78, 14:79, 15:80, 16:81, 17:82, 18:83, 19:84, 20:85, 21:86, 22:87, 23:88, 24:89, 25:90} valascii=dicascii[convertion]; resultat=chr(valascii) #On transforme le code ascii en caractere lisible sys.stdout.softspace=0 print resultat, k += 1 elif choixmenu == "2": #On veut decoder choixcle=raw_input("Type the word you want to use to decrypt your message: ") choixcle=choixcle.upper() message=raw_input("Type your message: ") message=message.upper() #On passe le message en majuscule savecle=[] savemess=[] k=0 l=0 for i in choixcle: valchiffre1=ord(i) #On recupere la valeur ascii de chaque lettre #On initialiste le dictionnaire qui fait la correspondance valeure ascii->chiffre normal dichiffre = {65:0, 66:1, 67:2, 68:3, 69:4, 70:5, 71:6, 72:7, 73:8, 74:9, 75:10, 76:11, 77:12, 78:13, 79:14, 80:15, 81:16, 82:17, 83:18, 84:19, 85:20, 86:21, 87:22, 88:23, 89:24, 90:25} clechiffre=dichiffre[valchiffre1] savecle.append(clechiffre) for j in message: valchiffre2=ord(j) #On recupere la valeur ascii de chaque lettre if (valchiffre2 >= 65) and (valchiffre2 <= 90): #On initialiste le dictionnaire qui fait la correspondance valeure ascii->chiffre normal dichiffre = {65:0, 66:1, 67:2, 68:3, 69:4, 70:5, 71:6, 72:7, 73:8, 74:9, 75:10, 76:11, 77:12, 78:13, 79:14, 80:15, 81:16, 82:17, 83:18, 84:19, 85:20, 86:21, 87:22, 88:23, 89:24, 90:25} messagechiffre=dichiffre[valchiffre2] savemess.append(messagechiffre) else: messagechiffre=valchiffre2 savemess.append(messagechiffre) while k < len(message): x=savemess[k] if (x >= 32) and (x <= 64) or (x >= 91) and (x <= 96) or (x >= 123) and (x <= 126): convertion=x valascii=convertion else: if l == len(choixcle): l=0 y=savecle[l] l += 1 else: y=savecle[l] l += 1 convertion=(x-y)%26 #On initialiste le dictionnaire qui fait la correspondance valeure chiffre normal->ascii dicascii = {0:65, 1:66, 2:67, 3:68, 4:69, 5:70, 6:71, 7:72, 8:73, 9:74, 10:75, 11:76, 12:77, 13:78, 14:79, 15:80, 16:81, 17:82, 18:83, 19:84, 20:85, 21:86, 22:87, 23:88, 24:89, 25:90} valascii=dicascii[convertion]; resultat=chr(valascii) #On transforme le code ascii en caractere lisible resultat=resultat.lower() sys.stdout.softspace=0 print resultat, k += 1

Choose 1 to crypt and 2 to decrypt
Type the word used for coding
Type the message

It is harder to decryot than Cesar cipher because it uses a polyaphabetic algorithm. The sentence is not coded with a letter but with a word. If you want to understand it better, visite this link:

http://en.wikipedia.org/wiki/Vigen%C3%A8re_cipher