#!/usr/bin/env python

# Written against python 3.3.1

# Matasano Problem 8

# Implement PKCS#7 padding

def addPKCS7Padding(data, blocksize):

numBytes = blocksize - (len(data) % blocksize);

for i in range(numBytes):

data += bytes(chr(numBytes), 'UTF-8');

return data

def test9():

input1 = b'abcd';

expected1 = b'abcd\x04\x04\x04\x04'

result1 = addPKCS7Padding(input1, 8);

if (expected1 != result1):

return False;

input2 = b'I am a little teapot short and stout';

expected2 = b'I am a little teapot short and stout\x0c\x0c\x0c\x0c\x0c\x0c\x0c\x0c\x0c\x0c\x0c\x0c'

result2 = addPKCS7Padding(input2, 16);

if (expected2 != result2):

return False;

input3 = b'Yellow Submarine'

expected3 = b'Yellow Submarine\x10\x10\x10\x10\x10\x10\x10\x10\x10\x10\x10\x10\x10\x10\x10\x10'

result3 = addPKCS7Padding(input3, 16);

if (expected3 != result3):

return False;

return True;

if __name__ == "__main__":

if (test9()):

print("Program 9 success");

else:

print("Failure");