Cryptography and Computer Network Security

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  BASIC CONCEPTS
KEY MANAGEMENT
  CLASSICAL CRYPTOALGORITHMS
  PUBLIC KEY CRYPTOALGORITHMS
  SECURITY SERVICES
  CRYPTOGRAPHIC STANDARDS AND SECURE INTERNET PROTOCOLS

 


BASIC CONCEPTS

 

  1. The need for security services in today's computer networks

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    Threats to computer security
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    Security services in computer networks and relationships among them:
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    confidentiality, integrity, authentication, non-repudiation
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    identification, access control, auditing
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    Electronic commerce and other applications of security services in today's computer networks
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    Survey of domestic and foreign cryptographic products


  3. Basic concepts of cryptology

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    Cryptosystem, plaintext, ciphertext, key
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    Examples of simple cryptosystems
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    To publish or not to publish?
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    Secret and open research in cryptology
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    Software vs. hardware implementations of cryptography
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    Evolution of cryptography and cryptanalysis.


  5. Types of cryptosystems. Implementation of security services

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    Classical (symmetric) vs. public key (asymmetric) cryptosystems
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    Trapdoor one-way functions - main components of public key cryptosystems
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    Features required from today's ciphers
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    Implementing security services using cryptographic transformations
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    Block vs. stream ciphers
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    Measures of the cipher strength


KEY MANAGEMENT


  1. Key Management

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    Session keys and key encrypting keys
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    Exchange of keys using Key Distribution Center
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    The Diffie-Hellman key exchange protocol
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    Exchange of symmetric keys using public key cryptosystems
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    Generation and registration of the public key pair
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    Concept of a public key certificate
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    Formats of certificates
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    Hierarchy of Certification Authorities - Public Key Infrastructure
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    Certificate revocation


  3. Pretty Good Privacy

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    E-mail Security
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    Implementation of Basic Security Services in PGP
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    General Format of PGP Messages
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    Key Rings
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    PGP Trust Model

     

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CLASSICAL CRYPTOALGORITHMS
  1. Mathematical Background

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    Motivation
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    Basic definitions
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    Laws of modular arithmetic
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    Euclid's algorithm
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    Extended Euclid's algorithm
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    Solving linear congruences

  3. Historical ciphers

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    Substitution ciphers
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    monoalphabetic
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    polyalphabetic
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    running-key
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    polygram
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    homophonic
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    Transposition ciphers
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    Breaking substitution ciphers using frequency analysis
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    Breaking polyalphabetic ciphers using Kasiski's method and method of the index of coincidance
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    Shannon's theory of perfect secrecy and its practical implications. One-time pad.
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    Product ciphers


  5. Data Encryption Standard - first attempt to standardize protection of information in public computer networks

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    History of the cryptosystem - the NBS-NSA-IBM roles
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    Acceptance by government and commercial sectors
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    Main features of the algorithm
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    Design criteria
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    Differential and linear cryptanalysis
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    Vulnerability to the exhaustive key search attack
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    Extensions of DES: Triple DES, DESX
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    Modes of operation
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    Security of different operational modes


  7. Modes of operation of block ciphers

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    Block ciphers vs. stream ciphers
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    CTR, OFB, CFB, CBC
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    Comparison of existing modes of operation
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    Evaluation criteria for new modes of operation
     
     
     
     
  8. Other symmetric-key block ciphers

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    IDEA
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    RC5
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    Fast software encryption cryptoalgorithms
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    Minimal key lengths for symmetric-key ciphers


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PUBLIC KEY CRYPTOALGORITHMS
  1. RSA – Genesis, operation & security. Factorization records.

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    Genesis of RSA
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    RSA as a trapdoor one-way function
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    Factorization as a basis of the RSA security
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    factorization records
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    factoring big numbers using a distributed network of computers
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    RSA challenge
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    Recommended key sizes for the RSA cryptosystem


  3. RSA Implementation: Efficient encryption, decryption & key generation

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    Basic exponentiation algorithm
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    Using Chinese Remainder Theorem for fast exponentiation
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    Basic algorithms for multiplication and modular reduction in software
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    Basic architectures for multiplication and modular reduction in hardware
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    Dependence between the key size and the times of cryptographic transformation
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    Probabilistic tests for primality
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    Deterministic tests for primality
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    Constructing a random prime
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    Optimal Assymetric Encryption Padding

     

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SECURITY SERVICES
  1. Data integrity and authentication - two faces of the same problem. Hash functions and MACs

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    Requirements for secure hash functions.
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    Classification of hash functions.
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    Attacks against hash functions.
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    Standard and non-standard applications of hash functions.
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    digital signatures and authentication codes
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    virus detection
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    password storage
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    fast encryption
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    Families of hash function algorithms and their security
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    Requirements for Message Authentication Code (MAC).
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    Families of MACs and their security.
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    Authentication combined with confidentiality.


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CRYPTOGRAPHIC STANDARDS AND SECURE INTERNET PROTOCOLS

  1. American and international cryptographic standards

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    Standard organizations
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    Main groups of cryptographic standards:
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    federal standards
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    ANSI standards
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    informal industry standards
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    IEEE standards
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    ISO standards
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    Classical cryptography standards
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    Public-key cryptography standards


  3. Secure Internet Protocols

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    Secure electronic mail
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    S/MIME
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    Open PGP
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    Secure WWW
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    SSL
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    Secure payment card protocols
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    Secure virtual private networks
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    IPSec


  5. Export and import control of cryptographic devices

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    Evolution of the U.S. policy
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    Current U.S. regulations

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