FilesExpand file tree

 master

/

CaesarBreaker.java

Copy path

Blame

More file actions

Blame

More file actions

Latest commit

 

History

History

History

60 lines (60 loc) · 2.06 KB

 master

/

CaesarBreaker.java

Copy path

Top

File metadata and controls

• Code
• Blame

60 lines (60 loc) · 2.06 KB

Raw

Copy raw file

Download raw file

Open symbols panel

Edit and raw actions

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

32

33

34

35

36

37

38

39

40

41

42

43

44

45

46

47

48

49

50

51

52

53

54

55

56

57

58

59

60

class CaesarBreaker{

public static String decryptTwoKeys(String encrypted){

String one = halfOfString(encrypted, 0);

String two = halfOfString(encrypted, 1);

int keyOne = getKey(one);

int keyTwo = getKey(two);

one = decrypt(one, keyOne);

two = decrypt(two, keyTwo);

StringBuilder sb = new StringBuilder();

int i = 0,j = 0;

System.out.println(one);

System.out.println(two);

while(i < one.length() || j < two.length()){

if(i < one.length()) sb.append(one.charAt(i++));

if(j < two.length()) sb.append(two.charAt(j++));

}

return sb.toString();

}

private static String decrypt(String str, int key){

key = 26 - key;

return new CaesarCipher().encrypt(str, key, key);

}

private static int getKey(String s){

int bias = maxIndex(countLetters(s));

return bias >= 4?bias-4:bias+26-4;

}

private static int maxIndex(int[] value){

int max = Integer.MIN_VALUE;

int index = -1;

for(int i = 0; i < value.length; ++i){

if(value[i] > max){

max = value[i];

index = i;

}

}

return index;

}

private static int[] countLetters(String str){

int[] count = new int[26];

str = str.toLowerCase();

for(int i = 0; i < str.length(); ++i){

if(!Character.isLetter(str.charAt(i))) continue;

count[(str.charAt(i)-'a')]++;

}

return count;

}

private static String halfOfString(String message, int start){

StringBuilder sb = new StringBuilder();

for(int i = start; i < message.length(); i+=2){

sb.append(message.charAt(i));

}

return sb.toString();

}

public static void main(String[] args){

//String message = "Akag tjw Xibhr awoa aoee xakex znxag xwko";

FileResource resource = new FileResource("lotsOfWords.txt");

String input = resource.asString();

System.out.println(decryptTwoKeys(message));

}

}