Python Programming in Context, 4th Edition

8.5 Summary

In this chapter, we explored cryptanalysis by implementing techniques for reading encrypted text. We utilized many previously introduced features of Python, including lists and dictionaries, but we extended these ideas by using lists and dictionaries as containers for other lists and dictionaries. We used a brute-force solution to systematically solve a challenging problem. Part of that solution used a pattern called “minmax” for systematically finding a “better” answer given a “best” answer so far. Finally, we introduced the notion of a regular expression and showed how this powerful pattern-matching tool can help us locate missing letters in partially decrypted text.