Problem set 4: the Caesar Cipher

Problem 3. Multi-level Encryption & Decryption 

Clearly the basic Caesar cipher is not terribly secure. To make things a little harder to crack, you 

will now implement a multi-level Caesar cipher. Instead of shifting the entire string by a single 

value, you will perform additional shifts at specified locations throughout the string. This 

function takes a string text and a list of tuples shifts. The tuples in shifts represent the location of 

the shift, and the shift itself. For example a tuple of (0,2) means that the shift starts are position 0 

in the string and is a Caesar shift of 2. Additionally, the shifts are layered. This means that a set 

of shifts [(0,2), (5, 3)] will first apply a Caesar shift of 2 to the entire string, and then apply a 

Caesar shift of 3 starting at the 6th letter in the string. 

To do this, implement the following function according to the specification. 

def apply_shifts(text, shifts): 

    """ 

    Applies a sequence of shifts to an input text. 

 

    text: A string to apply the Ceasar shifts to 

    shifts: A list of tuples containing the location each shift should 

    begin and the shift offset. Each tuple is of the form (location, 

    shift) The shifts are layered: each one is applied from its 

    starting position all the way through the end of the string. 

    returns: text after applying the shifts to the appropriate 

    positions 

 

    Example: 

    >>> apply_shifts("Do Androids Dream of Electric Sheep?", [(0,6), (3, 18), 

(12, 16)]) 

    'JufYkaolfapxQdrnzmasmRyrpfdvpmEurrb?' 

    """ 

    ### TODO.