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Diffie_Hellman_Presentation

Diffie_Hellman_Ppt

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Diffie_Hellman_Presentation

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  1. Diffie-Hellman Key Exchange Algorithm A 20-Slide Presentation

  2. Introduction • The Diffie-Hellman key exchange is a method of securely exchanging cryptographic keys over a public channel.

  3. Historical Background • Proposed by Whitfield Diffie and Martin Hellman in 1976, it was one of the first public-key protocols.

  4. Purpose • Allows two parties to establish a shared secret key that can be used for secure communication.

  5. Basic Idea • Two parties exchange values over a public channel to compute a common secret without directly transmitting it.

  6. Mathematical Foundation • Relies on modular arithmetic and the difficulty of solving discrete logarithm problems.

  7. Prime Number and Generator • A large prime number (p) and a generator (g) are chosen publicly.

  8. Private Keys • Each party chooses a private key: Alice chooses 'a' and Bob chooses 'b'.

  9. Public Keys • Alice computes g^a mod p, Bob computes g^b mod p, and they exchange these values.

  10. Shared Secret • Alice computes (g^b mod p)^a mod p, Bob computes (g^a mod p)^b mod p; both results are the same shared secret.

  11. Security Basis • The security relies on the difficulty of computing discrete logarithms in modular arithmetic.

  12. Step-by-Step Example • 1. p=23, g=5 • 2. Alice chooses a=6, computes 5^6 mod 23=8 • 3. Bob chooses b=15, computes 5^15 mod 23=19 • 4. Exchange values, shared secret=2.

  13. Man-in-the-Middle Attack • Without authentication, attackers can intercept and modify keys, leading to security risks.

  14. Use of Authentication • Digital signatures or certificates are often added to prevent man-in-the-middle attacks.

  15. Advantages • Provides secure key exchange without transmitting the secret directly.

  16. Limitations • Vulnerable without authentication, requires large primes for strong security.

  17. Applications • Used in TLS, VPNs, and other secure communication protocols.

  18. Variants • Elliptic Curve Diffie-Hellman (ECDH) offers similar security with smaller keys.

  19. Performance Considerations • Key size affects performance; ECDH is faster with smaller keys.

  20. Real-World Impact • Diffie-Hellman laid the foundation for modern public-key cryptography.

  21. Conclusion • The Diffie-Hellman algorithm remains a cornerstone of secure communications, enabling encrypted connections worldwide.

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