Basics of Cryptology – Part 19 (Cryptanalysis – Unicity Distance & Check and Proof Cipher Solutions)

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In this video, we show the basics of cryptology (cryptology = cryptography and cryptanalysis).

This video here gives an introduction to the unicity distance. Unicity distance is the minimum length of ciphertext needed of a given cipher, that if we would perform a brute-force search over all possible keys, there would be only one meaningful solution. Also, we discuss how to check and "proof" if a given solution (plaintext and/or key) to a ciphertext is the correct one.

First, we discuss the unicitiy distance and compute it for the simple monoalphabetic substitution cipher. Then, we discuss how to check ciphertext solutions. After that, we have a look at unicity distance in CrypTool 2 as well as check the solution of the Zodiac Killer's Z-408 cipher using the Homophonic Substitution Analyzer in CrypTool 2.

To see all videos in the "Basics of Cryptology" series, use this playlist: https://www.youtube.com/playlist?list=PLMuvAbyIl0PT6zaRVpK0FCSNMgwAOckTt

If you are interested in details about CrypTool 2, you may have a look at this video here, which gives a short introduction: https://www.youtube.com/watch?v=dELT2-Vgsr8

Finally, you may download the latest version of CrypTool 2 here: https://www.cryptool.org/en/ct2/downloads

Видео Basics of Cryptology – Part 19 (Cryptanalysis – Unicity Distance & Check and Proof Cipher Solutions) канала Cryptography for Everybody