Encryption Flashcards
Encryption
Using algorithm to change data so that it can only be read by the intended recipient
Decryption
Process of turning the encrypted data back into data that can be understood
Cipher
The algorithm which is used to encrypt or decrypt
Plaintext
Unencrypted message
Ciphertext
The encrypted message
Key
Data which defines how the plaintext was encrypted or how to decrypt it
Symmetric Wncryption
Same key is used for both encryption and decryption algorithms
Asymmetric Encryption
Different keys used for encryption and decryption
Caesar Cipher
Substitution cipher - symmetric encryption
Word structure preserved
Letter frequency big clue
Very quick to crack using brute force
Vernam Cipher
Uses randomly generated one time binary key
Same length as plain text
XORed with plaintext to produce ciphertext
Decrypted in same way using same key
~~~~~
No 2 bits encoded with same mapping
Mathematically secure
Keys are very large , secure distribution hard to achieve
Computational security
How difficult a cipher is to crack
Perfect security
Impossible to crack within a reasonable amount of time
