Lecture 2_Cryptography

Lecture 2_Cryptography - Conventional Encryption Message...

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Comp 6370 – Lecture 2 – Conventional Encryption 1 Conventional Encryption Message Confidentiality Slides modified from Henric Johnson Blekinge Institute of Technology, Sweden
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Comp 6370 – Lecture 2 – Conventional Encryption 2 This course is important Computer and Network Security is the antithesis of information warfare. “War is a matter of vital importance to the State; the province of life or death; the road to survival or ruin. It is mandatory that it be thoroughly studied.” Sun-Tzu
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Comp 6370 – Lecture 2 – Conventional Encryption 3 Administrative Comments Honor Unless otherwise specified, all work is an individual effort. Documentation of Written Work Late Penalties Project Suggestions Other questions Cumulative Exams? Sharing Notes? Pacing the course
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Comp 6370 – Lecture 2 – Conventional Encryption 4 Permissions Permissions Work is not turned in until the permissions are correct. You can ensure your permissions are correct by executing the following command: chmod 777 /class/comp6370/<directory>/<filename> rwx = 4+2+1 Verify permissions by executing: ls -al /class/comp6370/hw2/taylorb_hw2.txt.pgp
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Comp 6370 – Lecture 2 – Conventional Encryption 5 Factoring Primes Homework 3 Key Generation/Public Key Systems Factoring means finding a number’s prime factors Product of 2 primes – 5 * 7 = 35 35 factors into 5 * 7. 10 = 2 * 5 60 = 2 * 5 * 2 * 3 Keep this in mind for our discussion of public key systems next week.
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Comp 6370 – Lecture 2 – Conventional Encryption 6 Outline Outline Conventional Encryption Principles Conventional Encryption Algorithms Cipher Block Modes of Operation Location of Encryption Devices Key Distribution
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Comp 6370 – Lecture 2 – Conventional Encryption 7 Snake-Oil Cryptography (Matt Curtin) Check out: http://www.interhack.net/people/cmcurtin/snake-oil-faq.html “Trust Us, We Know What We're Doing” Techno-babble Secret Algorithms Revolutionary Breakthroughs Experienced Security Experts, Rave Reviews, and Other Useless Certificates Unbreakability One-Time-Pads Algorithm or product X is insecure Recoverable Keys Exportable from the USA “Military Grade”
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Comp 6370 – Lecture 2 – Conventional Encryption 8 One-Time Pads and “Venona” One-time pad: a randomly-generated, non-repeating key (length of the key at least equal to length of the message) is used only once. Perfect secrecy is achieved only with a perfect RNG. Quantum events, such as those measured by a geiger counter are believed to be the only source of truly random information. VENONA was the codename used for the U.S. Signals Intelligence effort to collect and decrypt the text of Soviet KGB and GRU messages from the 1940's.
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Lecture 2_Cryptography - Conventional Encryption Message...

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