Chp 2 Flashcards
Secret Key Encryption (Symmetric)
Makes use of a secret key for both encryption and decryption.
What is the challenge with secret keys?
How to securely transport them.
Diffie-Hellman
Widely used key exchange algorithm used for secret key transport in symmetric cryptography.
What are the two types of symmetric encryption?
Block and Stream
What is the difference between symmetric Block and Stream encryption?
Symmetric Block encryption groups data into a block and encrypts the individual block. Symmetric Stream encryption encrypts one bit at a time.
Where is symmetric stream encryption typically applied and why?
In real-time applications, it is much faster.
What is padding?
Filling the block to operating size, before encryption, when the data does not fit perfectly.
What do symmetric block ciphers manage?
How blocks of data are processed through block cipher mode implementations.
S-Box
Uses input and look-up tables to perform substitutions for ciphers.
Work Factor
The amount of time it takes to crack a cipher with the given computational power.
SALT
Adding an IV to the ciphering process to change its operation and ensure that the ciphertext does not give the plaintext when played back.
What is the function of the Block Cipher Mode?
To outline how the blocks will be handled.
Electronic Code Book (ECB)
Weak and insecure, each block is processed separately, and no SALT/IV is added so the ciphertext output will be the same every time the same plaintext is used as input.
Cipher Block Chaining (CBC)
Similar to ECB with the implementation of an IV. Results from the previous block are XOR’d with plaintext of the current block. That result is input to the encryption of the current block.
Cipher Feedback (CFB)
Converts the block cipher into a self-synchronizing stream cipher. The current block takes the output of the XOR process.
