Search Lesson Outline 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. Searching Lesson Outline How to Find a Value in an Array? Linear Search Linear Search Code Linear Search Example #1 Linear Search Example #2 Linear Search Example #3 Linear Search Example #4 Linear Search Example #5 Linear Search Example #6 How Long Does Linear Search Take? Linear Search: Best Case Linear Search: Worst Case Linear Search: Average Case Why Do We Care About Search Time? 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27. 28. 29. 30. 31. 32. 33. 34. “Big-O” Notation #1 “Big-O” Notation #2 “Big-O” Notation #4 “Big-O” Notation #5 “Big-O” Notation #6 Linear Search Code, Again Linear Search is O(n) in the Average Case A Better Search? Faster Search Requires Sorted Data Binary Search Binary Search Code Binary Search Code Binary Search Example #1 Binary Search Example #2 Binary Search Example #3 Time Complexity of Binary Search #1 Time Complexity of Binary Search #2 Time Complexity of Binary Search #3 Need to Sort Array Search Lesson CS1313 Fall 2018 1
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Multiple Encryption & DES  clearly a replacement for DES was needed   Vulnerable to brute-force key search attacks Can DES be patched and saved?
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Summary • Confidentiality with symmetric encryption  Symmetric encryption  Symmetric block encryption algorithms  Stream ciphers • Message authentication and hash functions  Authentication using symmetric encryption  Message authentication without message encryption  Secure hash functions  Other applications of hash functions • Random and pseudorandom numbers  The use of random numbers  Random versus pseudorandom • Public-key encryption     Structure Applications for public-key cryptosystems Requirements for public-key cryptography Asymmetric encryption algorithms • Digital signatures and key management     Digital signature Public-key certificates Symmetric key exchange using public-key encryption Digital envelopes • Practical Application: Encryption of Stored Data
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  EVALUATION RUBRIC DEVELOPED Below Expectations (1-2 Pts) Meets Expectations (3-4 Pts) Exceeds Expectations (5-6 Pts) POINTS Aspects of background or relevant external environment variables not discussed. Research is not thorough or is missing completely. Identified target market(s) do not follow clearly from any research presented. Provides analysis of all relevant background including competition and external environment. Some research undertaken to support analysis. Target market(s) identified. Could be clearer how research led to target market. Background is comprehensively examined and assessed. Competition, external environment, and any other relevant issues thoroughly researched and discussed. Research clearly supports target market(s) choice.   Objectives Communication objectives do not flow clearly from situation analysis. One or more objective may be difficult to measure, vague, and/or not clearly distinct from Marketing objectives. Complete communication objectives presented and follow reasonably well from situation analysis. Comm objectives are generally measurable and are distinguished from Marketing objectives. Communication objectives are clearly stated and flow fully and naturally from results of situation analysis. Objectives are specific, distinct from Marketing objectives, and measurable.   Message Strategy Basis of positioning is either missing or not presented clearly. If positioning is discussed, not clear what the connection between it and message strategy are. Message strategy is presented and positioning discussed but relationship between positioning platform and message strategy may not be totally clear. Message strategy is clearly presented and positions the product effectively. Positioning platform well-thought through and relationship between positioning and message are clear.   Media Strategy Important elements of media strategy may be missing. No clear connection between media & message strategies. Media strategy is presented and explained. Media strategy is reasonably consistent with message strategy. Media strategy is clearly presented. Media strategy supports and enhances message.   Other Plan Elements IMC plan omits one or more additional element that would contribute effectively. Appropriate public relations, direct marketing, Internet, sales promotion or support media are missing. IMC plan includes some additional elements that are appropriate. May include public relations, direct marketing, Internet, sales promotion or support media. IMC plan includes all additional elements that are appropriate (public relations, direct marketing, Internet, sales promotion, support media). Additional elements are clearly blended into positioning/message strategy.   Integration Lack of consistent message across two or more elements causes understanding of IMC to be questioned. Elements of IMC plan illustrate reasonable consistency and demonstrate understanding of the concept of IMC. The concept of IMC is clearly promoted and demonstrated through the consistent message woven throughout plan elements.   Budget Budget fails to clearly account for all plan items, does not support objectives, or is missing altogether. Full budget is presented and appears to support the plan’s objectives. All plan items accounted for in budget. Budget carefully and fully details each plan element. Supports stated objectives and is reasonable given any existing constraints.   Effectiveness Plan for measuring effectiveness of IMC plan is weak. Method choice questionable or plan is missing altogether. Plan for measuring effectiveness is presented. Choice of methods is reasonable. Measurement of all elements of IMC plan is clearly accounted for. Measurement methods are chosen/designed to produce clear results.   Situation Analysis
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Summary • • • • Denial-of-service attacks • • • • The nature of denial-of-service attacks Classic denial-of-service attacks Source address spoofing SYN spoofing Flooding attacks • • • ICMP flood UDP flood TCP SYN flood Defenses against denialof-service attacks Responding to a denialof-service attack • • • Distributed denialof-service attacks Application-based bandwidth attacks • • SIP flood HTTP-based attacks Reflector and amplifier attacks • • • Reflection attacks Amplification attacks DNS amplification attacks
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Public-key Encryption  Public-key encryption uses two different keys at once -- a private key and a public key.  The private key is known only to one computer, the public key is available to all.  Use the receiver’s public key to encrypt your message. Only the possessor of the private key can decrypt the message.  A message encrypted with a private key, can be decrypted with the corresponding public key.  The key pair is based on prime numbers (numbers that only have divisors of itself and one, such as 2, 3, 5, 7, 11 and so on) of long length.  The encryption is computationally intensive.  Used together with symmetric-key encryption. Succeeding with Technology – 3rd Edition
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Asymmetric Encryption Algorithms Key length Algorithm Diffie-Hellman (DH) (in bits) 512, 1024, 2048 Digital Signature Standard (DSS) and Digital Signature Algorithm (DSA) Description Public key algorithm invented in 1976 by Whitfield Diffie and Martin Hellman that allows two parties to agree on a key that they can use to encrypt messages. Security depends on the assumption that it is easy to raise a number to a certain power, but difficult to compute which power was used given the number and the outcome. Created by NIST and specifies DSA as the algorithm for digital signatures. 512 - 1024 DSA is a public key algorithm based on the ElGamal signature scheme. Signature creation speed is similar with RSA, but is 10 to 40 times as slow for verification. Developed by Ron Rivest, Adi Shamir, and Leonard Adleman at MIT in 1977. RSA encryption algorithms It is an algorithm for public-key cryptography based on the difficulty of factoring very large numbers. 512 to 2048 It is the first algorithm known to be suitable for signing as well as encryption, and one of the first great advances in public key cryptography. Widely used in electronic commerce protocols, and is believed to be secure given sufficiently long keys and the use of up-to-date implementations. An asymmetric key encryption algorithm for public-key cryptography which is based on the DiffieHellman key agreement. EIGamal 512 - 1024 Developed in 1984 and used in GNU Privacy Guard software, PGP, and other cryptosystems. A disadvantage is that the encrypted message becomes very big, about twice the size of the original message and for this reason it is only used for small messages such as secret keys. Elliptical curve techniques © 2012 Cisco and/or its affiliates. All rights reserved. Elliptic curve cryptography was invented by Neil Koblitz in 1987 and by Victor Miller in 1986. 160 Can be used to adapt many cryptographic algorithms, such as Diffie-Hellman or ElGamal. The main advantage of elliptic curve cryptography is that the keys can be much smaller. 126
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