ROT13 ŠIFRAS – TECHCODEVIEW.COM - IT PROBLEMOS IR SPRENDIMAI

ROT13 šifras (skaityti kaip – pasukti 13 vietų) yra ypatingas Ceaser šifro atvejis, kai poslinkis visada yra 13.
Taigi kiekviena raidė perkeliama 13 vietų, kad būtų galima užšifruoti arba iššifruoti pranešimą.

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Turite galvoti, kad tai tik dar vienas Cezario šifras kas šįkart kitaip? Na, skirtumas yra jo įgyvendinime. Metodas yra naudoti du atskirus python žodynus.

Pirmiausia reikia ieškoti įvairių raidžių pagal jų vietą anglų kalbos abėcėlėse, kad gautumėte perkeltą skaičių
Antrasis, kad gautumėte raides, atitinkančias tuos pasislinkusius skaičius.

Įgyvendinimas:

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>

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>

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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()>

C#

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

pakeisti iš eilutės java

Išvestis

TRRXF SBE TRRXF GEEKS FOR GEEKS>

Analizė: ROT13 šifras nėra labai saugus, nes tai tik ypatingas Cezario šifro atvejis. Cezario šifrą galima sugadinti atliekant dažnio analizę arba tiesiog išbandant visus 25 klavišus, o ROT13 šifrą galima sugadinti tiesiog perkeliant raides 13 vietų. Todėl jis neturi praktinės naudos.

Taikymas: ROT13 buvo naudojamas net.jokes naujienų grupėje devintojo dešimtmečio pradžioje.