![Step 1: Global Public Elements:
P: Any prime number [1024 to 4096 bits]
Step 3: User A Key Generation
G: Primitive Root of P
Step 2: Select private values for each user
Step 4: User B Key Generation
Step 5: Exchange of user keys from both sides
Step 6: Calculation of secret key by A
Step 7: Calculation of secret key by B
Step 8: The result is same secret key by using their own private keys
Algorithm](https://image.slidesharecdn.com/awsppt1-200304142607/85/Diffie-Hellman-Key-Exchange-20-320.jpg)
Diffie Hellman Key Exchange
- 1. Bansilal Ramnath Agarwal Charitable Trust's Vishwakarma Institute of Technology (An Autonomous Institute affiliated to Savitribai Phule Pune University) Contributed by, Saurabh Dhage(17C013) Balaji Channawar(17C017) Under Guidance of Prof. Ranjana Jadhav Masters in Computer Application (Second Year), IT-MCA Department Presentation on,
- 3. History Ralph Merkle, Martin Hellman, Whitefield Diffie (1977) • The Diffie-Hellman key exchange traces its roots back to the 1970s. • The two gatherings were working autonomously on the same issue - Diffie and Hellman on public key cryptography and Merkle on public key distribution - when they got to know about one another’s work and acknowledged there was collaboration in their methodologies • Whitfield Diffie and Martin Hellman published their paper, ’New Directions in Cryptography’. The collaboration outlined the mechanisms behind a new system, which would come to be known as the Diffie-Hellman key exchange. Diffie-Hellman key exchange
- 4. What is the Diffie-Hellman key exchange? • Diffie–Hellman key exchange is a method of securely exchanging cryptographic keys over a public channel • The Diffie-Hellman key exchange was the first widely used method of safely developing and exchanging keys over an insecure channel. • As one of the most common methods for safely distributing keys, the Diffie-Hellman key exchange is frequently implemented in security protocols such as TLS, IPsec, SSH, PGP, and many others.
- 5. How does the Diffie- Hellman key exchange work? Let’s take a example….
- 19. Algorithm
- 20. Step 1: Global Public Elements: P: Any prime number [1024 to 4096 bits] Step 3: User A Key Generation G: Primitive Root of P Step 2: Select private values for each user Step 4: User B Key Generation Step 5: Exchange of user keys from both sides Step 6: Calculation of secret key by A Step 7: Calculation of secret key by B Step 8: The result is same secret key by using their own private keys Algorithm
- 21. Advantages of the Diffie Hellman Algorithm The secret key is never itself transmitted over the channel Once the keys are exchanged, the communication of data can be done through an insecure channel. The sharing of the secret key is safe.
- 22. Cryptanalysis
- 23. • No Authentication : Algorithm does not provide authentication, which leaves users vulnerable to man- in-the-middle attacks • Parameters for number selection: If a real-world implementation of the Diffie-Hellman key exchange used numbers as small as those in our example, it would make the exchange process trivial for an attacker to crack. But it’s not just the size of the numbers that matter – the numbers also need to be sufficiently random. • Number of multiplications: All of the public information of a Diffie-Hellman key exchange was intercepted over an open channel including the number of multiplications (n) needed to calculate (g**b)**a mod p where `a` is Alice's private key and `b` is Bob's private key. This information should be enough to determine Alice's private key and then decrypt the message. Cryptanalysis
- 24. Applications of Diffie-Hellman Algorithm • Diffie Hellman is currently used in many protocols, namely: - Secure Sockets Layer(SSL)/Transport Layer Security (TLS) - Secure Shell(SSH) - Internet Protocol Security (IPsec) - Public Key Infrastructure (PKI)
- 25. Conclusion • Due to its advantages, the Diffie Hellman key Exchange has proved to be a useful key exchange system. • While it is really tough for someone snooping the network to decrypt the data and get the keys, it is still possible if the numbers generated are not entirely random or large. • Also, the key exchange system makes it possible to do a man in the middle attack, to avoid it, both parties should be very careful at the beginning of the exchange.
- 26. Thank you..