Code for Caesarcipher in Python

Security Algorithms/Cryptography/RSA Algortihm/CaesarCipher/Python/Caesarcipher.py

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+"""
+A Caesar Cipher function for both, encryption and decryption.
+After giving the string that you want, encryption will take place by shifting
+characters to the right and the decrypted string can be obtained by shifting
+the encrypted string to the left.
+The cipher is ready for Capital Letters only
+"""
+
+def encrypt(message,key):
+  ascii_vals_enc=[ord(c) for c in message]               #To get a list of ASCII Values of each character in string
+  for i in range(0,len(ascii_vals_enc)):
+    if(ascii_vals_enc[i]>=65 and ascii_vals_enc[i]<=90):
+	ascii_vals_enc[i] = 65 + (ascii_vals_enc[i] + key - 91)%26  #If the values in the list are greater than 65 and 90, we get it back b/w 65 and 90
+  encrypt_string = ''.join(chr(i) for i in ascii_vals_enc) # To get the encrypted string using the list of manipulated ASCII vals
+  return encrypt_string
+
+def decrypt(message,key):
+  ascii_vals_dec=[ord(c) for c in message]
+  for i in range(0,len(ascii_vals_dec)):
+    if(ascii_vals_dec[i]>=65 and ascii_vals_dec[i]<=90):
+	ascii_vals_dec[i] = 90 - (90 - ascii_vals_dec[i] + key )%26
+  decrypt_string = ''.join(chr(i) for i in ascii_vals_dec) # To get the decrypted string using the list of manipulated ASCII vals
+  return decrypt_string
+
+def caesar_cipher():
+  #message_enc = raw_input("Enter text to be encrypted:")	#Can be used to give custom strings
+  message_enc ="CODING IS FUN"	#string to be encrypted
+  encrypt_string = encrypt(message_enc,key)		#Calling the function to encrypt the string
+  print "The string to be encrypted is: ",message_enc
+  print "THe encrypted string is: ",encrypt_string
+  print "----------------------------------------"
+  #message_dec = raw_input("Enter text to be encrypted:")	#Can be used to give custom strings
+  message_dec ="M PSZI GSHMRK"	#string to be decrypted
+  decrypt_string = decrypt(message_dec,key)		#Calling the function to decrypt the string
+  print "The string to be decrypted is: ",message_dec
+  print "THe decrypted string is: ",decrypt_string
+
+if __name__=="__main__":
+  #key = int(raw_input("By what value do you want to shift?"))	#Can be used to give custom key values
+  key = 4
+  caesar_cipher()