Cryptography
- 1. ‘’ The Science of encrypTion ’’
- 2. • What is cryptography ? • Why cryptography is important ?
- 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. 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. HISTORY OF CRYPTOGRAPHY The history of cryptography can be divided into two parts: (1) From ancient civilizations to the 19th century and the first part of the 20th century, (2) Use of encrypting electro-mechanical machines, around the period of the WW II.
- 6. HISTORY OF CRYPTOGRAPHY Cryptography was used in three kinds of contexts in Cryptography:: ancient times Private communications Greek κρυπτός, kryptos, Art and religion "hidden, secret" Military and diplomatic use
- 7. MODERN CRYPTOGHRAPHY Here we have three types of algorithms that we can talk about: Secret Key Cryptography Hash Functions Public Key Cryptography
- 9. SECRET KEY CRYPTOGHRAPHY Secret Key(Symmetric) Cryptography uses a single key for both encryption and decryption.
- 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. SECRET KEY CRYPTOGHRAPHY Secret key cryptography algorithms that are in use today : Data Encryption Standard (DES): Advanced Encryption Standard (AES): International Data Encryption Algorithm (IDEA):
- 13. HASH FUNCTIONS Hash functions(One-way cryptography) have no key since plaintext cannot be recovered from the ciphertext.
- 14. HASH FUNCTIONS Called message compiler and one-way encryption No key is used Digital fingerprint Provide the integrity
- 15. HASH FUNCTIONS Hash algorithms that are in common use today: Message Digest (MD) algorithms: HAVAL (Hash of Variable Length): Tiger:
- 16. PUBLIC KEY CRYPTOGHRAPHY Public Key(Asymmetric) Cryptography. Two keys are used. One for encryption, one for decryption.
- 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. PUBLIC KEY CRYPTOGHRAPHY Mathematical Functions : Multiplication vs. factorization: Exponentiation vs. logarithms:
- 21. Why Three Encryption Techniques? Why are there so many different types of cryptographic schemes? Why can't we do everything we need with just one ?
- 22. THE SIGNIFICANCE OF PASSWORDS Every password can be decyrpted. In cryptography, size does matter.
- 23. How to create & use strong Passwords
- 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.