https://www.khanacademy.org/computing/computer-science/cryptography/crypt/v/intro-to-cryptography 2023-04-18T21:42:29.768102862Z What is cryptography? Cryptography has a rich history and plays a crucial role in modern communication networks. Learn about data encryption techniques through an example where Alice and Bob use secret codes (ciphers) to communicate privately. We'll learn about how encryption (locking messages) and decryption (unlocking messages) protect information from eavesdroppers like Eve.    Brit Cruise video https://cdn.kastatic.org/googleusercontent/CqAWCCyaRxvj3GfcWsDS_P-esRIiyL72aotktFxSohpP5eSdLsawhbPlIQlc5NYe1Q-qfoFA4BUWCI-F4oFlaX6PRg What is cryptography? Cryptography has a rich history and plays a crucial role in modern communication networks. Learn about data encryption techniques through an example where Alice and Bob use secret codes (ciphers) to communicate privately. We'll learn about how encryption (locking messages) and decryption (unlocking messages) protect information from eavesdroppers like Eve.    https://cdn.kastatic.org/ka-youtube-converted/Kf9KjCKmDcU.mp4/Kf9KjCKmDcU.mp4 91 Cryptography https://www.khanacademy.org/computing/computer-science/cryptography/crypt/v/caesar-cipher 2023-04-18T21:42:29.768102862Z The Caesar cipher The Caesar Cipher, used by Julius Caesar around 58 BC, is a substitution cipher that shifts letters in a message to make it unreadable if intercepted. To decrypt, the receiver reverses the shift. Arab mathematician Al-Kindi broke the Caesar Cipher using frequency analysis, which exploits patterns in letter frequencies. Brit Cruise video https://cdn.kastatic.org/googleusercontent/zYGRCWh5dppsV3Yr43IOtOp2U_JhdqgNmSXWbLXjXzuvA3EVzY6WAh8uOPqyK1lr11czN_tks3lGmSGdtlJWup8 The Caesar cipher The Caesar Cipher, used by Julius Caesar around 58 BC, is a substitution cipher that shifts letters in a message to make it unreadable if intercepted. To decrypt, the receiver reverses the shift. Arab mathematician Al-Kindi broke the Caesar Cipher using frequency analysis, which exploits patterns in letter frequencies. https://cdn.kastatic.org/ka-youtube-converted/sMOZf4GN3oc.mp4/sMOZf4GN3oc.mp4 157 Cryptography https://www.khanacademy.org/computing/computer-science/cryptography/crypt/pi/caesar-cipher-exploration 2022-09-10T01:34:41.474092194Z Caesar Cipher Exploration Type a message in the top box, then click and turn the wheel to encrypt it. interactive https://www.khanacademy.org/computing/computer-science/cryptography/crypt/pi/frequency-fingerprint-exploration 2022-09-10T01:34:41.474092194Z Frequency Fingerprint Exploration Did you know that when you communicate you are following a pattern without realizing it? <br> Questions: <br> 1. Why do we follow this pattern without thinking? <br> 2. Would it be different for different languages? <br> 3. How could we avoid this? interactive https://www.khanacademy.org/computing/computer-science/cryptography/crypt/v/polyalphabetic-cipher 2021-06-03T19:35:40Z Polyalphabetic cipher Brit introduces the polyalphabetic cipher, which creates a lighter fingerprint than the Caesar cipher. Brit Cruise video https://cdn.kastatic.org/googleusercontent/m1kwjAgwJ66x-39_i_Y4xauEIf8BE_sGlrOzUWsmf4I1wwiDRjIJo2ooEwRDK_-jT2vJdG_1DHtbdqJk7DbyBVKvSQ Polyalphabetic cipher Brit introduces the polyalphabetic cipher, which creates a lighter fingerprint than the Caesar cipher. https://cdn.kastatic.org/ka-youtube-converted/BgFJD7oCmDE.mp4/BgFJD7oCmDE.mp4 147 Cryptography https://www.khanacademy.org/computing/computer-science/cryptography/crypt/pi/polyalphabetic-exploration 2022-09-10T01:34:41.474092194Z Polyalphabetic Exploration Try out a polyalphabetic cipher interactive https://www.khanacademy.org/computing/computer-science/cryptography/crypt/v/perfect-secrecy 2021-03-22T14:52:38Z Perfect secrecy Claude Shannon's idea of perfect secrecy: no amount of computational power can help improve your ability to break the one-time pad Brit Cruise video https://cdn.kastatic.org/googleusercontent/oR19T86tK6rHScQUQvuYfV7wJdM2PO7TzvfZeQp5r5sO4TV95MhsvSTqgr7TvDHX-uaMMtHa5Od7xZ4xCN95psRppA Perfect secrecy Claude Shannon's idea of perfect secrecy: no amount of computational power can help improve your ability to break the one-time pad https://cdn.kastatic.org/ka-youtube-converted/vKRMWewGE9A.mp4/vKRMWewGE9A.mp4 253 Cryptography https://www.khanacademy.org/computing/computer-science/cryptography/crypt/pi/perfect-secrecy-exploration 2022-09-10T01:34:41.474092194Z Perfect Secrecy Exploration Explore how random shifts flatten your frequency fingerprint interactive https://www.khanacademy.org/computing/computer-science/cryptography/crypt/v/random-vs-pseudorandom-number-generators 2021-03-22T14:52:38Z Pseudorandom number generators Random vs. Pseudorandom Number Generators Brit Cruise video https://cdn.kastatic.org/googleusercontent/po8iWJVkEdYDt7gnDAF68_aJean5Fv-aWTf7A4vxRQ8oIkBiUQ1cGiSnvGNY2EpkqvQjb0tZX8cSvqgdwiA-NCZf Pseudorandom number generators Random vs. Pseudorandom Number Generators https://cdn.kastatic.org/ka-youtube-converted/GtOt7EBNEwQ.mp4/GtOt7EBNEwQ.mp4 401 Cryptography https://www.khanacademy.org/computing/computer-science/cryptography/crypt/pi/random-walk-exploration 2022-09-10T01:34:41.474092194Z Random Walk Exploration generate pseudorandom vs. random walks interactive