data security and service reliability

... to detect, prevent, or recover from a security attack.  Trang 64Aspects of Security• Security service: A processing or  communication service that enhances the  security of the data processing systems and the information transfers of an organization.  ... Reading and Web Sites 2.7 Key Terms and Review Questions Trang 13Course OutlineChapter 3 Block Ciphers and the Data Encryption Standard 3.1 Block Cipher Principles 3.2 The Data Encryption Standard ... Security Architecture 1.3 Security Attacks 1.4 Security Services 1.5 Security Mechanisms 1.6 A Model for Network Security 1.7 Recommended Reading and Web Sites 1.8 Key Terms and Review Questions

Ngày tải lên: 20/09/2020, 13:56

... to detect, prevent, or recover from a security attack.  29 Trang 30Aspects of Security• Security service: A processing or  communication service that enhances the  security of the data processing systems and the information transfers of an organization.  ... system 26 Trang 28Aspects of Security• Security attack: Any action that compromises the security of information owned by an  organization.  28 Trang 29Aspects of Security• Security mechanism: A process (or a device incorporating such a process) that is designed  ... 37Security Service– enhance security of data processing systems and  information transfers of an organization – intended to counter security attacks – using one or more security mechanisms  – often replicates functions normally associated with 

Ngày tải lên: 20/09/2020, 13:56

... 1(CSE348) Trang 2Lecture # 3Trang 3• Security concepts: – confidentiality, integrity, availability • Security attacks, services, mechanisms • Models for network (access) security • Classical Encryption ... attack, for various common key sizes Trang 8brute-Brute Force Search• Data Encryption Standard(DES) is 56 • Advanced Encryption Standard (AES) is 128 • Triple-DES is 168 Trang 9Brute Force Search• ... million keys per microsecond • And this performance level, DES can no longer be considered computationally secure. Trang 14Classical Substitution Ciphers• In this section and the next, we examine

Ngày tải lên: 20/09/2020, 13:57

... frequency data of the original alphabet 13 Trang 14• count relative letter frequencies (see text)• guess P & Z are e and t • guess ZW is th and hence ZWP is the • proceeding with trial and error ... each letter is replaced by the letter in the same row and in the column of the other letter of the pair 17 Trang 18Security of Playfair Cipher security much improved over monoalphabetic  since ... arbitrarily • each plaintext letter maps to a different random ciphertext letter • hence key is 26 letters long Trang 7Monoalphabetic Cipher Security• with so many keys, might think is secure •

Ngày tải lên: 20/09/2020, 13:57

... complete security but, in practice, has two fundamental difficulties: • There is the practical problem of making large quantities of random keys • And the problem of key distribution and protection ... needed by both sender and receiver • Because of these difficulties, the one-time pad is of limited utility, and is useful primarily for low-bandwidth channels requiring very high security • The one-time ... shown, cryptanalysis is fairly straightforward  and involves laying out the ciphertext in a matrix and playing around with column positions  Digram and trigram frequency tables can be useful 33

Ngày tải lên: 20/09/2020, 13:57

... techniques and terminology – monoalphabetic substitution ciphers – cryptanalysis using letter frequencies Trang 4Chapter 3 Block Ciphers and the Data Encryption Standard Trang 5Block Ciphers and the Data ... length 2w bits and a key K Trang 34Feistel Cipher Structure• The plaintext block is divided into two halves, L0 and R0 • The two halves of the data pass through n rounds of processing and then ... Trang 17Claude Shannon and Trang 18Claude Shannon and Substitution-Permutation Ciphers  In particular, Feistel proposed the use of a cipher that alternates substitutions and permutations  as

Ngày tải lên: 20/09/2020, 13:58

... structure Trang 4Data Encryption Standard (DES)• most widely used block cipher in world • adopted in 1977 by (National Bureau of Standards) NBS (now NIST) – as FIPS PUB 46 • encrypts 64-bit data using ... commercial cipher with input from NSA and others • In 1973 NBS issued request for proposals for a national cipher standard Trang 6DES Design Controversy• although DES standard is public • was considerable ... illustrated in Stallings Figure • which takes as input 64-bits of data and of key • The left side shows the basic process for enciphering a 64-bit data block which consists of: • an initial permutation

Ngày tải lên: 20/09/2020, 13:58

... Cryptanalysis Each round of DES maps the right-hand input into the left-hand output  Sets the right-hand output to be a function of the left-hand input and the subkey for this round  which means ... to result in random-looking changes to the output • The relationship should be nonlinear and difficult to approximate with linear functions • A final area of block cipher design, and one that ... function f  In differential cryptanalysis, we start with two messages, m and m', with a known XOR difference dm = m xor m',  and consider the difference between the intermediate message halves:

Ngày tải lên: 20/09/2020, 13:58

... Encryption Standard (AES) • Published by NIST (National Institute of Standards and Technology) in 2001 • AES is a symmetric block cipher • That is intended to replace DES as the approved standard for ... using a left circular shift and a permutation of the two 28-bit halves Trang 7Initial Permutation IP• The initial permutation and its inverse are defined by Tables 3.2a and 3.2b • The tables are ... illustrated in Stallings Figure • which takes as input 64-bits of data and of key • The left side shows the basic process for enciphering a 64-bit data block which consists of: • an initial permutation

Ngày tải lên: 20/09/2020, 13:59

... current block with a portion of the expanded key  This is the only step which makes use of the key and obscures the result, hence MUST be used at start and end of each round  Since otherwise ... of the matrix  which has larger coefficients, and is thus potentially a little harder & slower to implement  The designers & the AES standard provide an alternate characterization of ...  designed to be as simple as possible a form of Vernam cipher on expanded key requires other stages for complexity / security Trang 23Add Round Key23 Trang 24AES RoundTrang 25AES Key Expansion

Ngày tải lên: 20/09/2020, 13:59

... divisor of a and b Trang 17Greatest Common Divisor (GCD)• Positive integer c is said to be the greatest common divisor of a and b if c is a divisor of a and of b • and any divisor of a and b is a ... proceed to n, 2n, up to qn such that qn <= a and (q + 1)n > a • The distance from qn to a is r, and we have found the unique values of q and r Trang 16Greatest Common Divisor (GCD)• One ... and in encryption algorithms such as RSA • For given integers a and b, the extended Euclidean algorithm not only calculate the greatest common divisor d • but also two additional integers x and

Ngày tải lên: 20/09/2020, 13:59

... generator of the group Trang 10• and multiplication without leaving the set• and which obeys the associative and distributive laws Trang 11• With respect to addition and multiplication • The set ... of operator – example: a-3 = a.a.a • and let identity be: e=a0 • a group is cyclic if every element is a power of some fixed element – ie b = ak for some a and every b in group • a is said to ... with Extended Euclidean algorithm • Hence arithmetic is “well-behaved” and can do addition, subtraction, multiplication, and division without leaving the field GF(p) Trang 25• As can be seen,

Ngày tải lên: 20/09/2020, 13:59

... encrypted and transmitted immediately using a character-oriented stream cipher 39 Trang 40Stream Modes of Operation Block cipher as a pseudo-random number, and to combine these "random" ... blocks, Oi , depends only on the key and the IV, and does not depend on the plaintext 52 Trang 53Advantages and Limitations of OFB  Therefore, for a given key and IV, the stream of output bits ... is wasteful though, and slows the encryption down as more encryptions are needed  To generate a block of "random" bits, consume them as message bits/bytes arrive, and when they're used

Ngày tải lên: 20/09/2020, 13:59

... sequence and unpredictable  True random numbers are seldom used  Rather, sequences of numbers that appear to be random are generated by some algorithm Trang 10Random Numbers Many uses of random ... “randomness”  Known as “pseudorandom numbers”  Created by “Pseudorandom Number Generators (PRNGs)” Trang 12Random & Pseudorandom Number Generators  A true random number generator (TRNG) ... Trang 11Pseudorandom Number Generators (PRNGs) Often use deterministic algorithmic techniques to create “random numbers”  although are not truly random  can pass many tests of “randomness” 

Ngày tải lên: 20/09/2020, 14:00

... 1(CSE348) Trang 2Lecture # 15Trang 3 Pseudorandom number generation  True random numbers  Stream ciphers  RC4 Trang 4Chapter 9 – Public Key Cryptography and RSA Trang 5Every Egyptian received two ... received two names, which were known respectively as the true name and the good name, or the great name and the little name; and while the good or little name was made public, the true or great ... classical, and modern block and stream ciphers are of this form Trang 8Private-Key Cryptography Traditional private/secret/single key cryptography uses one key  Shared by both sender and receiver

Ngày tải lên: 20/09/2020, 14:00

... constraints on p and q: 1 p and q should differ in length by only a few digits Thus, for a 1024-bit key (309 decimal digits), both p and q should be on order of 1075 to 10100 2 Both (p – 1) and (q – ... primes at random - p, q – select either e or d and compute the other • Primes p,q must not be easily derived from modulus n=p.q – means must be sufficiently large – typically guess and use probabilistic ... finding primes and computing inverses • Both the prime generation and the derivation of a suitable pair of inverse exponents may involve Trang 30RSA Key Generation• Typically make random guesses

Ngày tải lên: 20/09/2020, 14:00

... fundamental and enabling service to achieve other aspects of data security within or beyond organizational boundaries Discussions in this part thus lays a foundation for solving other data security and ... data security and individual privacy in an ever more vulnerable state This thus motivates the need for protection of health data We next discuss the significance in maintaining data security and ... emergency access of health data From a technical perspective, data protection should be enforced upon data in storage, data in transmission, data in business transactions, and data in sharing As such,...

Ngày tải lên: 12/09/2015, 10:37

... accomplished? Overview of Security Policies The following is a list of standard common core security policies Data ownership, classification, and security Trans-border data flow Data and resource access ... users and vendors about their obligation for protection all data assets To establish the baseline data security stance and classification schema Data Security Policy - Structure and Guidelines ... Data Security Policy Data is considered a primary asset and as such must be protected in a manner commensurate to its value Data security is necessary in today's environment because data...

Ngày tải lên: 17/09/2012, 09:40

... for Voting System Security and Reliability 63 Summary of Selected Guidance on Information Technology Security and Reliability 78 Resolutions Related to Voting System Security and Reliability 84 ... Initiatives to Improve Voting System Security and Reliability Table 4: EAC Security and Reliability Practices for All Types of Voting Systems Table 5: EAC Security and Reliability Practices for Optical ... Election Reform Security and Reliability Practices for Voting Systems Table 11: Caltech/MIT Security and Reliability Practices for Voting Systems Table 12: Caltech/MIT Security and Reliability Practices...

Ngày tải lên: 23/03/2014, 03:20

... in data collection, storage, dissemination, and analysis " Data is everywhere, and with it are the clues to anticipate, prevent, and solve crimes; enhance security; and discover, detect, and ... techniques and tools to stem the flow of crime and terror and enhance security against individuals, property, companies, and civilized countries 1.12Criminal Analysis and Data Mining Data mining ... voicemail, and e-mail Coupled with data mining techniques, this expanded ability to access multiple and diverse databases will allow the expanded ability to predict crime Security and risk involving...

Ngày tải lên: 04/06/2014, 13:16