Merge pull request #22 from murugan-k-0204/main

Bacon Cipher and ROT13 Cipher python implementation

Author: itspyguru

decrypto/bacon_cipher.py

@@ -0,0 +1,49 @@
+class  BaconCipher:
+    def __init__(self) -> None:
+        self.baco_dict = { 
+                            'A':'aaaaa', 'B':'aaaab', 'C':'aaaba',
+                            'D':'aaabb', 'E':'aabaa', 'F':'aabab', 
+                            'G':'aabba', 'H':'aabbb', 'I':'abaaa', 
+                            'J':'abaab', 'K':'ababa', 'L':'ababb', 
+                            'M':'abbaa', 'N':'abbab', 'O':'abbba',
+                            'P':'abbbb', 'Q':'baaaa', 'R':'baaab', 
+                            'S':'baaba', 'T':'baabb', 'U':'babaa', 
+                            'V':'babab', 'W':'babba', 'X':'babbb', 
+                            'Y':'bbaaa', 'Z':'bbaab'
+        }
+        self.reverse_baco = { 
+            self.baco_dict[key] : key for key in self.baco_dict }
+
+    def encrypt(self, message : str) -> str:
+        cipher = ''
+        for letter in message.upper():
+            # checks for space
+            if(letter != ' '):
+                # adds the ciphertext corresponding to the 
+                # plaintext from the dictionary
+                cipher += self.baco_dict[letter]
+            else:
+                # adds space
+                cipher += ' '
+        return cipher
+
+    def decrypt(self,message):
+        decipher = ''
+        i = 0
+        while True :
+            if(i < len(message)-4):
+                # extracting a set of ciphertext
+                # from the message which is of size 5
+                substr = message[i:i + 5]
+                # checking for space as the first 
+                # character of the substring
+                if(substr[0] != ' '):
+                    decipher += self.reverse_baco[substr]
+                    i += 5 # to get the next set of ciphertext
+                else:
+                    # adds space
+                    decipher += ' '
+                    i += 1 # index next to the space
+            else:
+                break
+        return decipher

decrypto/rot13_cipher.py

@@ -0,0 +1,27 @@
+class ROT13Cipher:
+    def __init__(self) -> None:
+        pass
+
+    def encrypt(self, message):
+        cipher = ''
+        for letter in message.upper():
+            # checking for space
+            if(letter != ' '):
+                num = chr((ord(letter) - ord('A') + 13 ) % 26 + ord('A'))
+                cipher += num
+            else:
+                # adds space
+                cipher += ' '
+        return cipher
+
+    def decrypt(self, message):
+        decipher = ''
+        for letter in message.upper():
+            # checks for space
+            if(letter != ' '):
+                num = chr(((ord(letter) - ord('A') - 13 + 26) % 26) + ord('A'))
+                decipher += num
+            else:
+                # adds space
+                decipher += ' '
+        return decipher