Initial commit

Author: ppeuchin

caesar_cipher.py

@@ -0,0 +1,45 @@
+#Caeser Cipher Algorithm for encryption and decryption
+
+def caesar_encryption(plaintext, key):
+    encrypted_str = ""
+    for i in plaintext:
+        if i.isupper():
+            uni_value = 65 + ((ord(i) - 65 + key) % 26)
+            encrypted_str = encrypted_str + chr(uni_value)
+        elif i.islower():
+            uni_value = 97 + ((ord(i) - 97 + key) % 26)
+            encrypted_str = encrypted_str + chr(uni_value)
+        else:
+            encrypted_str = encrypted_str + i
+    
+    print("The encrypted text is:", encrypted_str)
+
+plaintext = input("Enter the text: ")
+key = int(input("Enter the key: "))
+caesar_encryption(plaintext, key)
+
+def caesar_decryption(ciphertext, key):
+    decrypted_str = ""
+    for i in ciphertext:
+        if i.isupper():
+            if (ord(i) - 65 - key) < 0:
+                uni_value = 65 + ((ord(i) - 65 - key) + 26) % 26
+                decrypted_str = decrypted_str + chr(uni_value)
+            else:
+                uni_value = 65 + (ord(i) - 65 - key) % 26
+                decrypted_str = decrypted_str + chr(uni_value)
+        elif i.islower():
+            if (ord(i) - 97 - key) < 0:
+                uni_value = 97 + ((ord(i) - 97 - key) + 26) % 26
+                decrypted_str = decrypted_str + chr(uni_value)
+            else:
+                uni_value = 97 + (ord(i) - 97 - key) % 26
+                decrypted_str = decrypted_str + chr(uni_value)
+        else:
+            decrypted_str = decrypted_str + i
+
+    print("The decrypted text is:", decrypted_str)       
+
+ciphertext = input("Enter the encrypted text: ")
+key = int(input("Enter the key:"))
+caesar_decryption(ciphertext, key)