ROT13-CHIFFER - TECHCODEVIEW.COM - IT-PROBLEM OCH LÖSNINGAR

ROT13-chiffer (läs som – rotera med 13 platser) är ett specialfall av Ceaser-chifferet där skiftet alltid är 13.
Så varje bokstav flyttas 13 platser för att kryptera eller dekryptera meddelandet.

Du måste tro att det bara är ännu ett caesarchiffer så vad är annorlunda den här gången? Skillnaden är väl i dess genomförande. Tillvägagångssättet är att använda två separata python-ordböcker.

Den första att slå upp de olika bokstäverna efter deras plats i de engelska alfabeten för att få det förskjutna numret
Den andra för att få bokstäverna som motsvarar de förskjutna siffrorna.

Genomförande:

C++

// CPP program to implement> // ROT13 Caesar Cipher> #include> using> namespace> std;> // Map to lookup the index of alphabets> map <>char>,>int>>dict1;> // Map to lookup alphabets corresponding> // to the index after shift> map <>int>,>char>>dict2;> // 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>

c struktur i struktur

Java

// 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>

Python3

heapify sortera

# 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()>

C#

java konvertera sträng till int

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>>dict1 =>new> Dictionary<>char>,>int>>();> >// Map to lookup alphabets corresponding> >// to the index after shift> >public> static> Dictionary<>int>,>char>>dict2 =>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.>

Javascript

// 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>

Produktion

TRRXF SBE TRRXF GEEKS FOR GEEKS>

Analys: ROT13-chifferet är inte särskilt säkert eftersom det bara är ett specialfall av Caesar-chifferet. Caesar-chifferet kan brytas antingen genom frekvensanalys eller genom att bara prova alla 25 nycklar, medan ROT13-chifferet kan brytas genom att bara flytta bokstäverna 13 platser. Därför har den ingen praktisk användning.

Ansökan: ROT13 användes i nyhetsgruppen net.jokes i början av 1980-talet.