Section 8.71 Asymmetric Algorithms

Question 1

Asymmetric Algorithms

Answer 1

Does not require a shared secret key, often referred to as public key cryptograpy since their key is considered to be freely and openly available to the public

Uses a key pair

● Public key for encryption
● Private key for decryption

■ Provides confidentiality, integrity, authentication, and non-repudiation

Question 2

Confidentiality with Public Key

Answer 2

■ Encrypt data using the receiver’s public key

■ Only the recipient with the corresponding private key can decrypt it

Question 3

Non-Repudiation with Private Key

Answer 3

■ Encrypt data using the sender’s private key

■ Anyone with access to the sender’s public key can verify the sender’s identity

Question 4

Integrity and Authentication with Digital Signature

Answer 4

■ Create a hash digest of the message and Encrypt the hash digest with the sender’s private key to create a Digital Signature

■ Encrypt the message with the receiver’s public key

■ Reciever decrypts the message with their own Private Key and fetches the senders Public Key to decrypt the Hash Digest. Reciever then runs the message/data through a hashing algorithm to verify its an identical Hash Digest

■ Ensures message integrity, non-repudiation, and confidentiality

Digital Signature: A hash digest of a message encrypted with the sender’s private key to let the recipient know the document was created and sent by the person claiming to have sent it

Question 5

Common Asymmetric Algorithms

Diffie-Hellman

Answer 5

● Used for key exchange and secure key distribution. It is commonly used in VPN tunnel establishment (IPSec)

● Vulnerable to man-in-the-middle attacks, requires authentication

Question 6

Common Asymmetric Algorithms

RSA (Ron Rivest, Adi Shamir, Leonard Adleman)

Answer 6

Asymmetric algorithm that relies on the mathematical difficulty of factoring large prime numbers

● Supports key sizes from 1024 to 4096 bits

● Widely used in organizations and multi-factor authentication

Question 7

Common Asymmetric Algorithms

Elliptic Curve Cryptography (ECC)

Answer 7

Heavily used in MOBILE devices and LESS POWERFUL DEVICES and it’s based on the algebraic structure of elliptical curves over finite fields to define its keys

● Six times more efficient than RSA for equivalent security

ECC witrh a 256-bit key is just as secure as a RSA with a 2048-bit key

● Variants include:

○ ECDH (Elliptic Curve Diffie-Hellman)
○ ECDHE (Elliptic Curve Diffie-Hellman Ephemeral)
○ ECDSA (Elliptic Curve Digital Signature Algorithm)