1    a = 'Wkh_Txlfn_Eurzq_Ira_Mxpsv_Ryhu_Wkh_Odcb_Grj'
2    import string
3    def rotn(n):
4        from string import ascii_lowercase as lc, ascii_uppercase as uc
5        mapping = string.maketrans(lc + uc, lc[n:] + lc[:n] + uc[n:] + uc[:n])
6        return mapping
7    for n in xrange(26):
8       a.translate(rotn(n))

 1 use 5.010;
 2 use warnings;
 3 
 4 my $original = lc "Ceterum censeo Carthaginem esse delendam";
 5 
 6 my $cyphered = $original;
 7 $cyphered =~ tr/a-z/k-za-j/;
 8 say $cyphered;
 9 
10 my $decyphered = $cyphered;
11 $decyphered =~ tr/k-za-j/a-z/;
12 say $decyphered;

 1 class Caesar
 2   def initialize(shift, alphabet = ('a'..'z').to_a.join)
 3     i = shift % alphabet.size #I like this
 4     @decrypt = alphabet
 5     @encrypt = alphabet[i..-1] + alphabet[0...i]
 6   end
 7 
 8   def encrypt(string)
 9     string.tr(@decrypt, @encrypt)
10   end
11 
12   def decrypt(string)
13     string.tr(@encrypt, @decrypt)
14   end
15 end

 1  private final String ALPHABET = "abcdefghijklmnopqrstuvwxyz";
 2  public String encrypt(String plainText,int shiftKey)
 3  {
 4        plainText = plainText.toLowerCase();
 5        String cipherText="";
 6        for(int i=0;i<plainText.length();i++)
 7        {
 8             int charPosition = ALPHABET.indexOf(plainText.charAt(i));
 9             int keyVal = (shiftKey+charPosition)%26;
10             char replaceVal = this.ALPHABET.charAt(keyVal);
11             cipherText += replaceVal;
12        }
13        return cipherText;
14  }
15  public String decrypt(String cipherText, int shiftKey)
16  {
17        cipherText = cipherText.toLowerCase();
18        String plainText="";
19 }