chars = ["a","b","c","d","e","f","g","h","i","j","k","l","m","n","o","p","q","r","s","t","u","v","w","x","y","z","A","B","C","D","E","F","G","H","I","J", "K","L","M","N","O","P","Q","R","S","T","U","V","W","X","Y","Z","0","1","2","3","4","5","6","7","8","9"]

class CipherShell:
    def __init__(self):
    	"""Initializes the cipher."""
        raise NotImplementedError

    def encrypt(self,msg):
    	"""Encrypts the given message."""
        raise NotImplementedError
    
    def decrypt(self,msg):
    	"""Decrypts the given encrypted message."""
        raise NotImplementedError
    
    def get_state(self):
    	"""Returns the state of the cipher."""
        raise NotImplementedError
    
    def set_state(self,state):
    	"""Sets the state of the cipher."""
        raise NotImplementedError