Public Key Crptography (week 10) Flashcards
(40 cards)
What principle did William Stanley Jevons illustrate with his factorisation example?
The difficulty of reversing factorisation underpins RSA security.
Who invented the RSA algorithm?
Ron Rivest, Adi Shamir, and Leonard Adleman.
What are the key components required for RSA key generation?
Two large prime numbers (p, q) and a public/private key pair.
How does public key encryption ensure confidentiality?
The sender encrypts data with the recipient’s public key; only the recipient can decrypt it using their private key.
What is non-repudiation in public key cryptography?
Proof that a message was sent by the claimed sender.
Why is encrypting the entire document often unnecessary in practice?
Encrypting a hash is faster and provides equivalent authenticity.
What are the two processes combined for confidentiality and authentication?
Encrypting with the recipient’s public key and signing with the sender’s private key.
How can Bob verify Linda’s identity using public key cryptography?
Using Linda’s public key to decrypt her signed message.
What is a Certificate Authority (CA)?
An entity that issues digital certificates to verify identities.
What role does a Registration Authority (RA) play in public key infrastructure?
It verifies user requests before certificates are issued.
What is the Web of Trust model?
A decentralized method where users vouch for each other’s keys.
Why is the Web of Trust difficult to manage in practice?
Trust chains can be complex and difficult to maintain.
What is the primary role of Pretty Good Privacy (PGP)?
Encrypting and signing emails for privacy and authentication.
How does the Estonian ID-Card model ensure public key verification?
Through government-backed digital certificates.
What are the key properties of cryptographic hash functions?
Deterministic, fast, irreversible, and collision-resistant.
Why is MD5 considered flawed for modern security purposes?
It is vulnerable to collision attacks.
What hash algorithm is recommended for modern applications?
SHA-256 or SHA-3.
How does Linux secure passwords using hashing and salts?
By combining a password with a unique salt before hashing.
What is the purpose of a Message Authentication Code (MAC)?
To ensure data integrity and authenticity.
How does a Digital Signature ensure message authenticity?
By signing the message with the sender’s private key.
What is the Diffie-Hellman key exchange?
A method for securely exchanging cryptographic keys.
Why is public key cryptography not used for real-time encryption?
It is slower than symmetric encryption methods.
What vulnerability exists in the Diffie-Hellman exchange?
Man-in-the-middle attacks if authentication isn’t applied.
How can you mitigate a man-in-the-middle (MITM) attack in Diffie-Hellman?
Use digital certificates to verify identity.
