Vigenere Cypher THE VIGENERE CYPHER IS AN EXAMPLE OF A SIMPLE ENCRYPTION SCHEME WITH A LARGE SET OF KEY POSSIBILITIES. IN THE VIGENERE CYPHER, A WORD (OR PHRASE) IS USED AS THE KEY. COPIES OF THE KEY ARE MATCHED UP WITH THE LETTERS OF THE PLAINTEXT MESSAGE. FOR EXAMPLE, WITH KEY = "CAT", AND MESSAGE = "MEET ME AT" WE GET THE MATCHING = M E E T M E A T C A T C A T C A T C EACH CHARACTER IN THE KEY IS TREATED AS THE KEY FOR A SHIFT CYPHER.

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This page is part of a section of lecture slides related to " Traditional Cryptography " within the topic "Privacy Issues and Encryption". Other slides within this section and other sections of slides for the topic "Privacy Issues and Encryption" can be accessed using the links below. Electronic Privacy Threats Internet Eavesdropping Who can you Trust? Secure Web Communications Traditional Cryptography Encryption Basics Cryptographic Notation The Caesar Cipher Key-based Encryption Schemes Generalizing the Caesar Cipher More Notation Key Properties Vigenere Cypher Vigenere Cypher (cont.) The Key Distribution Problem Public Key Cryptography Public Key Cryptography Public Key Distribution The RSA Cryptosystem Some Details of the RSA Cryptosystem Some Details of the RSA Cryptosystem (cont.) Properties of the RSA Cryptosystem Authentication Authentication Authentication and the Internet Authentication and Cryptography Digital Signatures? Digital Signatures (cont.) Authenticity with Secrecy Certifying Authorities Certifying Authorities (cont.) Data Gathering vs. Privacy "Passive" Privacy Threats HTTP Protocol Headers Server Response Headers Web Browser Headers What are "Magic Cookies"? Magic Cookies Data Mining Passive Privacy and Encryption Techniques Digital Cash Anonymous Internet Financial Transactions Commutative Encryption Blank Bills Withdrawal Symptoms Making Money A Spending Spree