1. CS2910 Week 10, Class 1 Today Modular Arithmetic RSA Week 10, Monday Quiz: Potential topics TCP window size & header format Public/private key encryption (Is covered in afternoon section) Sharing symmetric keys Applying a stream cipher Known-plaintext attack Unicode, UTF-8 encoding, and quoted-printable May include some questions requiring you to interpret or create raw data SE-2811 Slide design: Dr. Mark L. Hornick Content: Dr. Hornick Errors: Dr. Yoder 1

2. Final Exam (Morning) CS 2910 001 Yoder Wednesday 11:00 AM - 1:00 PM L304 (Morning) CS 2910 002 Yoder Wednesday 11:00 AM - 1:00 PM L305 SE-2811 Dr.Yoder 2

3. WWII Encryption: The Enigma Machine A story of a known- plaintext attack http://www.cnet.com/pi ctures/breaking-the- nazis-enigma-codes- at-bletchley-park- photos/2/ SE-2811 Dr.Yoder 3

4. WWII Encryption: The Enigma and the Bomb Mavis Batey SE-2811 Dr.Yoder 4

5. Video Questions: TODO UPDATE So if a key is only shared between two people, that means there must be a unique key for every pair? Also, when keys are generated, how are they shared securely over networks?? Are there standard encryption/decryption algorithms or do companies create and adopt their own? Would a company have different algorithms for each program or would they have a standard? How are modern day encryption keys generated and how do those work? Is there any way to tell whether a message has been manipulated/accessed in transmission due to a cryptographic attack? SE-2811 Dr.Yoder 5

6. SE-2811 Dr. Josiah Yoder 6