Cryptography

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Detailed Presentation about password security

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Cryptography

  1. 1. ‘’ The Science of encrypTion ’’
  2. 2. • What is cryptography ?• Why cryptography is important ?
  3. 3. Contents• The purpose of cryptography• History of cryptography and cryptanalysis• Modern cryptography(Types of Algorithms) - Secret Key Cryptography - Hash Functions - Public Key Cryptography - Why Three Encryption Techniques? - The Significance of Passwords & Password Security• Conclusion
  4. 4. THE PURPOSE OF CRYPTOGRAPHYSpecific security requirements for communication: Data transfer and telecommunication Science of communications code Computer writing in secret Authentication: Privacy/confidentiality: Integrity: Non-repudiation:
  5. 5. HISTORY OF CRYPTOGRAPHYThe history of cryptography can be divided into twoparts:(1) From ancient civilizations to the 19th century and thefirst part of the 20th century,(2) Use of encrypting electro-mechanicalmachines, around the period of the WW II.
  6. 6. HISTORY OF CRYPTOGRAPHYCryptography was used in three kinds of contexts inCryptography::ancient times Private communicationsGreek κρυπτός, kryptos, Art and religion"hidden, secret" Military and diplomatic use
  7. 7. MODERN CRYPTOGHRAPHYHere we have three types of algorithms that we cantalk about: Secret Key Cryptography Hash Functions Public Key Cryptography
  8. 8. MODERN CRYPTOGHRAPHY
  9. 9. SECRET KEY CRYPTOGHRAPHY Secret Key(Symmetric) Cryptography uses a single key for both encryption and decryption.
  10. 10. SECRET KEY CRYPTOGHRAPHY A single key is used Sender uses the key to encrypt Receiver uses the same key to decrypt Key must be known to both the sender and the receiver The difficulty is the distribution of the key
  11. 11. SECRET KEY CRYPTOGHRAPHYSecret key cryptography algorithms that are in usetoday : Data Encryption Standard (DES): Advanced Encryption Standard (AES): International Data Encryption Algorithm (IDEA):
  12. 12. SECRET KEY SUMMARY
  13. 13. HASH FUNCTIONS Hash functions(One-way cryptography) have no key since plaintext cannot be recovered from the ciphertext.
  14. 14. HASH FUNCTIONS Called message compiler and one-way encryption No key is used Digital fingerprint Provide the integrity
  15. 15. HASH FUNCTIONSHash algorithms that are in common use today: Message Digest (MD) algorithms: HAVAL (Hash of Variable Length): Tiger:
  16. 16. PUBLIC KEY CRYPTOGHRAPHY Public Key(Asymmetric) Cryptography. Two keys are used. One for encryption, one for decryption.
  17. 17. PUBLIC KEY CRYPTOGHRAPHY Developed in the last 300-400 years. Martin Hellman and graduate student Whitfield Diffie A two-key crypto system Mathematical functions
  18. 18. PUBLIC KEY CRYPTOGHRAPHYMathematical Functions : Multiplication vs. factorization: Exponentiation vs. logarithms:
  19. 19. PUBLIC KEY CRYPTOGHRAPHY
  20. 20. PUBLIC KEY SUMMARY
  21. 21. Why Three Encryption Techniques? Why are there so many different types of cryptographic schemes? Why cant we do everything we need with just one ?
  22. 22. THE SIGNIFICANCE OF PASSWORDS Every password can be decyrpted. In cryptography, size does matter.
  23. 23. How to create & use strong Passwords
  24. 24. How to create & use strong Passwords Use lengthy passwords. THANK YOU symbols. Combine letters, numbers, and FOR LISTENING TO US (: Use words and phrases.

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