Encryption Flashcards
What is encryption
Using an algorithm to change data so it can only be read by the intended receiver
What is decryption
Turning the encrypted data back into data that can be understood
What is a cipher
The algorithm which is used to encrypt or decrypt
What is plaintext
The unencrypted message
What is ciphertext
The encrypted message
What is the key(encryption)
Data which define how the plaintext was encrypted and how to decrypt it
What is symmetric encryption
The same key is used for encryption and decryption
What is Asymmetric encryption
Different keys are used for encryption and decryption
What is a Caesar cipher
Type of substitution cipher
Replaces plaintext letters with a different one a fixed number of places down the alphabet
Uses symmetric encryption
Name a disadvantage of using the Ceasar cipher for encryption
Word Structure is preserved
Letter frequency is unchanged - making it easier to find the cipher
quick to crack using brute force
What is the Vernam Cipher
Uses randomly generated one time binary key that is
- Same length as plaintext
- XORed with plaintext to produce ciphertext
- Decrypted in the same way with the same key
Name an advantage and disadvantage of using the Vernam Cipher for encryption
Adv
- No two bites are encoded with the same mapping
- Mathematically secure
Dis
- Keys are very large
What is Computation Security/Hardness
Refers to how difficult a cipher is to crack
What is perfect security
The cipher is impossible to crack in a reasonable amount of time
