Cracking Codes with Python: An Introduction to Building and Breaking Ciphers
by Al Sweigart (Author)
Booktalk: Learn how to program in Python while making and breaking ciphers–algorithms used to create and send secret messages! You’ll begin with simple programs for the reverse and Caesar ciphers and then work your way up to public key cryptography, the type of encryption used to secure today’s online transactions, including digital signatures, email, and Bitcoin.
Snippet: Imagine you know someone on the other side of the world who wants to communicate with you. You both know that spy agencies are monitoring all emails, letters, texts, and phone calls. To send a secret message to that person, you both must agree on a secret key to use. But if one of you emails the secret key to the other, the spy agency will intercept this key and then decrypt any future messages using that key. Secretly meeting in person to exchange the key is impossible. You can try encrypting the key, but this requires sending that secret key to the other person, which will also be intercepted.
Public key cryptography solves this encryption problem by using two keys, one for encryption and one for decryption, and is an example of an asymmetric cipher.
It’s STEM Friday! (STEM is Science, Technology, Engineering, and Mathematics)
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