def ascii_encrypt(plaintext):
    return ''.join(chr(ord(x)+i) for i,x in enumerate(plaintext))
    
def ascii_decrypt(plaintext):
    return ''.join(chr(ord(x)-i) for i,x in enumerate(plaintext))

'''
Ascii Shift Encryption/Decryption

The goal of this kata is to create a very simple ASCII encryption and decryption.
 The encryption algorithm should change each character relative to its location in the string.
 
Example:

  P | A | S | S | W | O | R | D # Plaintext
+ 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 # Shift (add)
  P | B | U | V | [ | T | X | K # Ciphertext

The decryption should reverse this:

  P | B | U | V | [ | T | X | K # Ciphertext
- 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 # Shift (subtract)
  P | A | S | S | W | O | R | D # Plaintext

You may assume input string will be :

    uppercase letters only
    length < 26


'''