Podcast
Questions and Answers
What is the key used in symmetric encryption called?
What is the key used in symmetric encryption called?
What is the relationship between the sender and receiver in public-key cryptography?
What is the relationship between the sender and receiver in public-key cryptography?
Which of the following is not a common application of public-key cryptography?
Which of the following is not a common application of public-key cryptography?
What is the main purpose of using public-key cryptography for digital signatures?
What is the main purpose of using public-key cryptography for digital signatures?
Signup and view all the answers
Which of the following algorithms is an example of a public-key cryptography algorithm?
Which of the following algorithms is an example of a public-key cryptography algorithm?
Signup and view all the answers
What is the primary difference between symmetric and asymmetric cryptography?
What is the primary difference between symmetric and asymmetric cryptography?
Signup and view all the answers
What is the purpose of using public-key cryptography for key exchange?
What is the purpose of using public-key cryptography for key exchange?
Signup and view all the answers
Which of the following statements about symmetric and asymmetric cryptography is true?
Which of the following statements about symmetric and asymmetric cryptography is true?
Signup and view all the answers
What is the primary advantage of using public-key cryptography over symmetric cryptography?
What is the primary advantage of using public-key cryptography over symmetric cryptography?
Signup and view all the answers
Which of the following statements about the DES and RSA algorithms is correct?
Which of the following statements about the DES and RSA algorithms is correct?
Signup and view all the answers
Study Notes
Diffie-Hellman Key Exchange
- Diffie-Hellman (DH) key exchange technique was first defined in 1976 by Diffie and Hellman.
- DH key exchange is a method of exchanging public information to obtain a shared secret.
- DH is not an encryption algorithm.
- DH key exchange has three important properties:
- The resulting shared secret cannot be computed by either of the parties without the cooperation of the other.
- A third party observing all the messages transmitted during DH key exchange cannot deduce the resulting shared secret.
- The shared secret is symmetric, meaning both parties have the same key.
Diffie-Hellman Key Exchange Process
- System parameters are public and include a large prime number p and a primitive root g.
- Alice and Bob exchange public keys, each computed using their private random values and the system parameters.
- Alice and Bob calculate the shared secret key using their private random values and the public keys exchanged.
Diffie-Hellman Mathematical Analysis
- Alice and Bob agree on public parameters p and g.
- Alice generates a private random value a and computes a public key ga mod p.
- Bob generates a private random value b and computes a public key gb mod p.
- Alice and Bob exchange public keys and compute the shared secret key.
Man-in-the-Middle Attack
- An attacker, Fred, can intercept public keys and compute a fake public key.
- Alice and Bob will compute a shared secret key with the attacker, but not with each other.
Public Key Cryptography
- Public-key cryptography is a radical departure from symmetric cryptography.
- Each user has a public key and a private key.
- Public-key cryptography provides confidentiality, authentication, and key distribution.
Properties of Public Key Cryptography
- The encryption key is not the same as the decryption key.
- Public-key cryptography is asymmetric, using two separate keys.
- Public-key cryptography provides a solution to key distribution and authentication problems.
History of Public Key Cryptography
- 1976: Diffie and Hellman published an article on public-key cryptography and introduced the concept of key exchange.
- 1977: Rivest, Shamir, and Adleman invented the RSA scheme.
- Later: Many other public-key cryptography methods were developed, including El Gamal, DSS, and DH.
Symmetric vs Public-Key Cryptography
- Symmetric cryptography uses the same algorithm with the same key for encryption and decryption.
- Public-key cryptography uses a pair of keys, one for encryption and one for decryption.
- Symmetric cryptography is also known as private-key cryptography, while public-key cryptography is asymmetric.
Applications of Public-Key Cryptosystems
- Encryption/decryption: using the recipient's public key to encrypt a message.
- Digital signature: using the sender's private key to sign a message.
- Key exchange: exchanging a session key between two parties.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
Test your knowledge about the Diffie-Hellman (DH) key exchange technique, which allows for secure communication over an insecure channel. Learn about the properties and significance of DH key exchange in cryptography.
