Szyfr ROT13 (czytaj: obróć o 13 miejsc) jest szczególnym przypadkiem szyfru Ceasera, w którym przesunięcie wynosi zawsze 13.
Zatem każda litera jest przesuwana o 13 miejsc w celu zaszyfrowania lub odszyfrowania wiadomości.
Musisz myśleć, że to tylko kolejny szyfr Cezara co jest innego tym razem? Cóż, różnica polega na jego implementacji. Podejście polega na użyciu dwóch oddzielnych słowników Pythona.
- Pierwszy, który wyszuka różne litery według ich miejsca w alfabecie angielskim, aby uzyskać przesuniętą liczbę
- Drugi, aby uzyskać litery odpowiadające przesuniętym cyfrom.
Realizacja:
C++
// CPP program to implement> // ROT13 Caesar Cipher> #include> using> namespace> std;> // Map to lookup the index of alphabets> map <>char>,>int>>dykt1;> // Map to lookup alphabets corresponding> // to the index after shift> map <>int>,>char>>dykt2;> // Function to create map to lookup> void> create_dict()> {> >for>(>int> i = 1; i <27; i++)> >dict1[>char>(64 + i)] = i;> > >dict2[0] =>'Z'>;> > >for>(>int> i = 1; i <26; i++)> >dict2[i] =>char>(64 + i);> > >return>;> }> // Function to encrypt the string> // according to the shift provided> string encrypt(string message,>int> shift)> {> >string cipher =>''>;> >for>(>int> i = 0; i { // Checking for namespace if(message[i] != ' ') { // looks up the map and // adds the shift to the index int num = (dict1[message[i]] + shift) % 26; // looks up the second map for the // shifted alphabets and adds them cipher += dict2[num]; } else { // adds space cipher += ' '; } } return cipher; } // Function to decrypt the string // according to the shift provided string decrypt(string message, int shift) { string decipher = ''; for(int i = 0; i { // checks for space if(message[i] != ' ') { // looks up the map and // subtracts the shift to the index int num = (dict1[message[i]] - shift + 26) % 26; // looks up the second map for the // shifted alphabets and adds them decipher += dict2[num]; } else { // adds space decipher += ' '; } } return decipher; } // Driver code int main() { create_dict(); string message = 'GEEKS FOR GEEKS'; int shift = 13; cout << encrypt(message, shift) << '
'; message = 'TRRXF SBE TRRXF'; shift = 13; cout << decrypt(message, shift) << '
'; return 0; } // This code is contributed by Sachin Bisht> |
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Jawa
// java program for the above approach> import> java.util.*;> public> class> Main {> >// Map to lookup the index of alphabets> >static> Map dict1 =>new> HashMap();> >// Map to lookup alphabets corresponding> >// to the index after shift> >static> Map dict2 =>new> HashMap();> >// Function to create map to lookup> >static> void> create_dict() {> >for>(>int> i =>1>; i <>27>; i++)> >dict1.put((>char>)(>64> + i), i);> >dict2.put(>0>,>'Z'>);> >for>(>int> i =>1>; i <>26>; i++)> >dict2.put(i, (>char>)(>64> + i));> >}> >// Function to encrypt the string> >// according to the shift provided> >static> String encrypt(String message,>int> shift) {> >String cipher =>''>;> >for>(>int> i =>0>; i // Checking for namespace if(message.charAt(i) != ' ') { // looks up the map and // adds the shift to the index int num = (dict1.get(message.charAt(i)) + shift) % 26; // looks up the second map for the // shifted alphabets and adds them cipher += dict2.get(num); } else { // adds space cipher += ' '; } } return cipher; } // Function to decrypt the string // according to the shift provided static String decrypt(String message, int shift) { String decipher = ''; for(int i = 0; i // checks for space if(message.charAt(i) != ' ') { // looks up the map and // subtracts the shift to the index int num = (dict1.get(message.charAt(i)) - shift + 26) % 26; // looks up the second map for the // shifted alphabets and adds them decipher += dict2.get(num); } else { // adds space decipher += ' '; } } return decipher; } // Driver code public static void main(String[] args) { create_dict(); String message = 'GEEKS FOR GEEKS'; int shift = 13; System.out.println(encrypt(message, shift)); message = 'TRRXF SBE TRRXF'; shift = 13; System.out.println(decrypt(message, shift)); } } // This code is contributed by prince> |
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Python3
# Python program to implement> # ROT13 Caesar cipher> '''This script uses dictionaries instead of 'chr()' & 'ord()' function'''> # Dictionary to lookup the index of alphabets> dict1>=> {>'A'> :>1>,>'B'> :>2>,>'C'> :>3>,>'D'> :>4>,>'E'> :>5>,> >'F'> :>6>,>'G'> :>7>,>'H'> :>8>,>'I'> :>9>,>'J'> :>10>,> >'K'> :>11>,>'L'> :>12>,>'M'> :>13>,>'N'> :>14>,>'O'> :>15>,> >'P'> :>16>,>'Q'> :>17>,>'R'> :>18>,>'S'> :>19>,>'T'> :>20>,> >'U'> :>21>,>'V'> :>22>,>'W'> :>23>,>'X'> :>24>,>'Y'> :>25>,>'Z'> :>26>}> # Dictionary to lookup alphabets> # corresponding to the index after shift> dict2>=> {>0> :>'Z'>,>1> :>'A'>,>2> :>'B'>,>3> :>'C'>,>4> :>'D'>,>5> :>'E'>,> >6> :>'F'>,>7> :>'G'>,>8> :>'H'>,>9> :>'I'>,>10> :>'J'>,> >11> :>'K'>,>12> :>'L'>,>13> :>'M'>,>14> :>'N'>,>15> :>'O'>,> >16> :>'P'>,>17> :>'Q'>,>18> :>'R'>,>19> :>'S'>,>20> :>'T'>,> >21> :>'U'>,>22> :>'V'>,>23> :>'W'>,>24> :>'X'>,>25> :>'Y'>}> # Function to encrypt the string> # according to the shift provided> def> encrypt(message, shift):> >cipher>=> ''> >for> letter>in> message:> ># checking for space> >if>(letter !>=> ' '>):> ># looks up the dictionary and> ># adds the shift to the index> >num>=> ( dict1[letter]>+> shift )>%> 26> ># looks up the second dictionary for> ># the shifted alphabets and adds them> >cipher>+>=> dict2[num]> >else>:> ># adds space> >cipher>+>=> ' '> >return> cipher> # Function to decrypt the string> # according to the shift provided> def> decrypt(message, shift):> >decipher>=> ''> >for> letter>in> message:> ># checks for space> >if>(letter !>=> ' '>):> ># looks up the dictionary and> ># subtracts the shift to the index> >num>=> ( dict1[letter]>-> shift>+> 26>)>%> 26> ># looks up the second dictionary for the> ># shifted alphabets and adds them> >decipher>+>=> dict2[num]> >else>:> ># adds space> >decipher>+>=> ' '> >return> decipher> # driver function to run the program> def> main():> ># use 'upper()' function to convert any lowercase characters to uppercase> >message>=> 'GEEKS FOR GEEKS'> >shift>=> 13> >result>=> encrypt(message.upper(), shift)> >print> (result)> >message>=> 'TRRXF SBE TRRXF'> >shift>=> 13> >result>=> decrypt(message.upper(), shift)> >print> (result)> # Executes the main function> if> __name__>=>=> '__main__'>:> >main()> |
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C#
using> System;> using> System.Collections;> using> System.Collections.Generic;> using> System.Linq;> // C# program for the above approach> class> HelloWorld {> > >// Map to lookup the index of alphabets> >public> static> Dictionary<>char>,>int>>dykt1 =>new> Dictionary<>char>,>int>>();> >// Map to lookup alphabets corresponding> >// to the index after shift> >public> static> Dictionary<>int>,>char>>dykt2 =>new> Dictionary<>int>,>char>>();> >// Function to create map to lookup> >public> static> void> create_dict() {> >for>(>int> i = 1; i <27; i++)> >dict1.Add((>char>)(64 + i), i);> >dict2.Add(0,>'Z'>);> >for>(>int> i = 1; i <26; i++)> >dict2.Add(i, (>char>)(64 + i));> >}> >// Function to encrypt the string> >// according to the shift provided> >public> static> string> encrypt(>string> message,>int> shift) {> >string> cipher =>''>;> >for>(>int> i = 0; i // Checking for namespace if(message[i] != ' ') { // looks up the map and // adds the shift to the index int num = (dict1[message[i]] + shift) % 26; // looks up the second map for the // shifted alphabets and adds them cipher += dict2[num]; } else { // adds space cipher += ' '; } } return cipher; } // Function to decrypt the string // according to the shift provided public static string decrypt(string message, int shift) { string decipher = ''; for(int i = 0; i // checks for space if(message[i] != ' ') { // looks up the map and // subtracts the shift to the index int num = (dict1[message[i]]- shift + 26) % 26; // looks up the second map for the // shifted alphabets and adds them decipher += dict2[num]; } else { // adds space decipher += ' '; } } return decipher; } static void Main() { create_dict(); string message = 'GEEKS FOR GEEKS'; int shift = 13; Console.WriteLine(encrypt(message, shift)); message = 'TRRXF SBE TRRXF'; shift = 13; Console.WriteLine(decrypt(message, shift)); } } // The code is contributed by Nidhi goel.> |
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JavaScript
ciąg int
// Dictionary to lookup the index of alphabets> const dict1 = {>'A'>: 1,>'B'>: 2,>'C'>: 3,>'D'>: 4,>'E'>: 5,> >'F'>: 6,>'G'>: 7,>'H'>: 8,>'I'>: 9,>'J'>: 10,> >'K'>: 11,>'L'>: 12,>'M'>: 13,>'N'>: 14,>'O'>: 15,> >'P'>: 16,>'Q'>: 17,>'R'>: 18,>'S'>: 19,>'T'>: 20,> >'U'>: 21,>'V'>: 22,>'W'>: 23,>'X'>: 24,>'Y'>: 25,>'Z'>: 26};> // Dictionary to lookup alphabets> // corresponding to the index after shift> const dict2 = {0:>'Z'>, 1:>'A'>, 2:>'B'>, 3:>'C'>, 4:>'D'>, 5:>'E'>,> >6:>'F'>, 7:>'G'>, 8:>'H'>, 9:>'I'>, 10:>'J'>,> >11:>'K'>, 12:>'L'>, 13:>'M'>, 14:>'N'>, 15:>'O'>,> >16:>'P'>, 17:>'Q'>, 18:>'R'>, 19:>'S'>, 20:>'T'>,> >21:>'U'>, 22:>'V'>, 23:>'W'>, 24:>'X'>, 25:>'Y'>};> // Function to encrypt the string> // according to the shift provided> function> encrypt(message, shift) {> >let cipher =>''>;> >for> (let i = 0; i const letter = message[i]; // checking for space if (letter !== ' ') { // looks up the dictionary and // adds the shift to the index const num = (dict1[letter] + shift) % 26; // looks up the second dictionary for // the shifted alphabets and adds them cipher += dict2[num]; } else { // adds space cipher += ' '; } } return cipher; } // Function to decrypt the string // according to the shift provided function decrypt(message, shift) { let decipher = ''; for (let i = 0; i const letter = message[i]; // checks for space if (letter !== ' ') { // looks up the dictionary and // subtracts the shift to the index const num = (dict1[letter] - shift + 26) % 26; // looks up the second dictionary for the // shifted alphabets and adds them decipher += dict2[num]; } else { // adds space decipher += ' '; } } return decipher; } // driver function to run the program function main() { // use 'toUpperCase()' function to convert any lowercase characters to uppercase let message = 'GEEKS FOR GEEKS'; let shift = 13; let result = encrypt(message.toUpperCase(), shift); console.log(result); message = 'TRRXF SBE TRRXF'; shift = 13; result = decrypt(message.toUpperCase(), shift); console.log(result); } main(); // This code is contributed by adityashatmfh> |
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>Wyjście
TRRXF SBE TRRXF GEEKS FOR GEEKS>
Analiza: Szyfr ROT13 nie jest zbyt bezpieczny, ponieważ jest to tylko szczególny przypadek szyfru Cezara. Szyfr Cezara można złamać albo poprzez analizę częstotliwości, albo po prostu wypróbowując wszystkie 25 kluczy, podczas gdy szyfr ROT13 można złamać, po prostu przesuwając litery o 13 miejsc. Dlatego nie ma praktycznego zastosowania.
Aplikacja: ROT13 był używany w grupie dyskusyjnej net.jokes na początku lat 80-tych.