Dion Cryptography - pg86 Flashcards
What is cryptogrpahy?
A way to hide the true meaning of information.
What is encryption?
Process of converting ordinary information into an unintelligible form.
What is Data at Rest?
Inactive data that is stored on a hard drive or other storage device.
What is Data in Transit?
Data that is moving between devices - on the internet, crossing the network, or data in a computer’s memory.
What is Data in Use?
Data that is currently being processed - in the CPU.
What is ROT13
A rotation cypher that moves the letters of the alphabet 13 times.
What is plain text?
The initial message that has not yet been encrypted.
What is ciphertext?
The message once it has been encrypted.
What is more important when strengthening encryption? The key or the algorithm?
The Key!!
What is an encryption key?
The essential piece of info that determines the output of a cipher.
What is symmetric encryption?
Uses an encryption algorithm, where the sender and receives must have the same key.
Confidentiality is assured.
What is symmetric encryption also known as?
Private Key
How can you distribute the key for symmetric encryption?
By using asymmetric encryption!
What are the 9 symmetric algorithms?
- DES
- 3DES
- IDEA
- AES
- Blowfish
- Twofish
- RC4
- RC5
- RC6
What is asymmetric encryption?
Use two keys - public and private, to encrypt and decrypt data
Name the 3 asymmetric algorithms
- Diffie-Hellman
- RSA
- ECC
Which is faster - symmetric or Asymmetric? By how much?
Symmetric by 100-1000x faster!
What is hybrid Implementation?
Uses asymmetric encryption to transfer a private key to be used with symmetric encyrption
What is a Stream Cipher?
Uses a keystream generator to encrypt bit by bit using XOR function to create ciphertext.
What is a Block Cipher?
Breaks up data into fixed length blocks, which are then encrypted.
Easy to use with software.
What is DES?
Data Encryption Standard
16 round
64 bit blocks
Uses a 56 bit encryption key
What is 3DES?
Triple DES
Uses 3 symmetric keys, one after another
What is IDEA?
International Data Encryption Algorithm
Symmetric Block Cipher
64-bit block
What is AES?
What are the 3 bit block lengths that can be used
Advanced Encryption Standard
Symmetric Block Cipher
128, 192, 256 bit blocks and MATCHing key size.
Standard for US Gov
What is Blowfish?
Symmetric Block Cipher
64 bit block
Variable length key
Replaced by Twofish!
What is Twofish?
Symmetric Block Cipher
128 bit blocks
128, 192, 256 bit keys
Replaced blowfish
What is RC4?
Rivest Cipher 4
Symmetric STREAM cipher (the only one on the exam!!!)
Variable key size from 40 bits to 2048 bits.
Used in SSL and WEP
What is RC5?
Rivest Cipher 5
Symmetric Block Cipher
Key size up to 2040 bits
What is RC6?
Rivest Cipher 6
Symmetric Block Cipher developed to replace DES but AES won!
What is asymmetric cryptography also know as?
What 4 things does it provide?
Public Key Cryptography
- Confidentiality
- Integrity
- Authentication
- Non-repudiation
What is a digital signature?
A hash digest of a message encrypted with the sender’s private key, which is sent and then decrypted with your public key and checked to see if it is the same.
What is PKI?
Public Key Infrastructure
What is DH?
Diffie Hellman Algorithm
Asymmetric
Used to conduct key exchanges
Used to establish VPN tunnels using IPSec
What is RSA?
Rivest, Shamir and Adleman
- Asymmetric
- Uses prime numbers
- Used widely for key exchange, encryption and digital signatures
Key size from 1024 - 4096bits!
What is ECC?
Elliptic Curve Cryptography
- Asymmetric
- Uses algebraic structure of elliptic curves over finite fields to make keys
- Used for low-power computing (mobiles)
Which ECC key length is the same secure level as an RSA 2048-bit key?
256 bit key!
What are the 3 sub types of ECC?
ECDH - Elliptic Curve Diffie-Hellman
ECDHE - Elliptic Curve Diffie-Hellman Ephemeral
ECDSA - Elliptic Curve Digital Signature Algo
