Cracking Codes with Python

8DECRYPTING WITH THE TRANSPOSITION CIPHER

“Weakening encryption or creating backdoors to encrypted devices and data for use by the good guys would actually create vulnerabilities to be exploited by the bad guys.”—Tim Cook, CEO of Apple, 2015

Unlike the Caesar cipher, the decryption process for the transposition cipher is different from the encryption process. In this chapter, you’ll create a separate program named transpositionDecrypt.py to handle decryption.

TOPICS COVERED IN THIS CHAPTER

• Decrypting with the transposition cipher

• The round(), math.ceil(), and math.floor() functions

• The and and or Boolean operators

• Truth tables

How to Decrypt ...