[Python-Dev] Conversion of a standard unicode string to a bit string in Python

Hi All, I'm currently programming a set of crypto challenges in order to get a deeper understanding of python and crypto. The problem is to break a repeating key xor data (in a file). In order to do that I need a function to calculate the hamming distance between two strings. To find that one needs to find the differing number of *bits* in a string. Any ideas on how to manipulate the string at bit level? This is my first time in writing a question to the mailing list so please let me know anything that I need to keep in mind while asking questions. Thanks in advance. Gracias Nemo