Fixed Caesar Cipher Implementation

Caesar_Cipher/Caesar_cipher.py

@@ -1,45 +1,43 @@
-class main: 
-    def __init__(self,key:dict) -> None:
+class Cipher:
+    def __init__(self, key: dict) -> None:
         self.key = key
-
-    def get_input(self) -> None: 
+        self.rev_key = {v: k for k, v in key.items()}  # reverse mapping
+
+    def get_input(self) -> None:
         while True:
-            blank_string = str(input("Enter string to decrypt: "))
-            if blank_string.isalpha():
-                blank_string = blank_string.lower()
-                self.blank_string = blank_string
+            text = input("Enter string to encrypt: ").strip()
+            if text.isalpha():
+                self.blank_string = text.lower()
                 break
             else:
-                print("Input is not valid")
-                continue
-
+                print("Input is not valid! Only alphabets allowed.")
+
     def encrypt_string(self) -> str:
         output = ""
         for c in self.blank_string:
-            for k,v in self.key.items():
-                if k == c:
-                    output += v
-                else:
-                    continue
-        self.decrypted_string = output
-        return(output)
-
+            output += self.key.get(c, c)
+        return output
+
     def decrypt_string(self, string: str) -> str:
-        output = "" 
-        string = string.lower()
-        string = string.strip()
+        string = string.strip().lower()
         if string == "":
-            return(self.blank_string)
-        else: 
-            for c in string:
-                for k,v in self.key.items():
-                    if v == c:
-                        output += k
-
-        return(output)
+            return self.blank_string
+        output = ""
+        for c in string:
+            output += self.rev_key.get(c, c)
+        return output
 
 if __name__ == "__main__":
-    key ={"a": "d", "b": "e", "c": "f", "d": "g", "e": "h", "f": "i", "g": "j", "h": "k", "i": "l", "j": "m", "k": "n", "l": "o", "m": "p", "n": "q", "o": "r", "p": "s", "q": "t", "r": "u", "s": "v", "t": "w", "u": "x", "v": "y", "w": "z", "x": "a", "y": "b", "z": "c"}
-    main = main(key=key)
-    main.get_input()
-    print(main.encrypt_string())
+    # Fixed: Caesar cipher with shift of 3 (properly wrapping around)
+    key = {
+        "a": "d", "b": "e", "c": "f", "d": "g", "e": "h", "f": "i", "g": "j",
+        "h": "k", "i": "l", "j": "m", "k": "n", "l": "o", "m": "p", "n": "q",
+        "o": "r", "p": "s", "q": "t", "r": "u", "s": "v", "t": "w", "u": "x",
+        "v": "y", "w": "z", "x": "a", "y": "b", "z": "c"
+    }
+
+    cipher = Cipher(key)
+    cipher.get_input()
+    encrypted = cipher.encrypt_string()
+    print("Encrypted:", encrypted)
+    print("Decrypted:", cipher.decrypt_string(encrypted))

Caesar_Cipher/README.md

@@ -26,8 +26,12 @@ The script was created with Python3 and the built-in functions in it
 <!--Remove the below lines and add yours -->
 ```bash
 python3 caesarcypher.py 
-Enter string to decrypt: hello
+Enter string to encrypt: hello
 khoor
+
+Enter string to decrypt: khoor
+hello
+
 ```
 ## 📺 Demo
 <p align="center">