Basics Of Crypto Flashcards
What are the drawbacks of using a symmetric key cipher?
Requires a secure method of key transfer
Must be stored securely
What is a random number generator?
A secure pseudorandom number generator used for algorithms
Explain DES?
- block cipher with 64-bit blocks
- no longer considered secure
- short key length
- brute force attacks easy
Explain 3DES?
- replacement for DES
- applies DES 3 times to each block
Explain IDEA?
International data encryption algorithm
- 128-bit block cipher
- intended as replacement for DES
Explain AES?
- designed as replacement for DES
- a different number of rounds for each key length
- key schedule allows weakness
Explain RC4?
- generates pseudo-random keystream
- keystream XORed with plaintext to create cipher
Explain asymmetric key encryption?
- uses two mathematically related keys
- one to encrypt, one to decrypt
- public key can be freely sent over insecure network
- private key must be private
Weakness of asymmetric cipher?
- Easy one way, difficult the other
- Security if private key must be maintained
Explain man in the middle attacks?
- pure victim to fill in authentication over a supposedly secure link
- att lets intercepts
Explain RSA?
- generates asymmetric key pairs
- often used to secure transfer of symmetric keys
- superseded by elliptic curve
What is modular arithmetic?
- underlies many public-key algorithms
- Uses extremely large modulus
Explain RSA key generation?
- two prime numbers
- n = p x q
Weaknesses of RSA algorithm?
- security rests on two mathematical problems
- quantum computers can break RSA
Explain diffie-hellman?
Two parties establish a shared secret key
