Created by Jörg Schwartz
almost 4 years ago


Question  Answer 
Define \[\textit{plaintext}\]\[\textit{ciphertext}\]  \(\textit{plaintext}\) is the original message in readable form \(\textit{ciphertext}\) is the encrypted message 
Method of cryptography Caesar employed?  \(\textit{shiftcipher}\), since every letter in the alphabet is shifted up or down 
Define \[\textit{simple substitution cipher}\]  A cipher in which each symbol is replaced by another symbol 
Convenient way to describe the encryption and decryption function of a simple substitution cipher  Create a table by writing the plaintext resp. ciphertext alphabet in the top row and putting the ciphertext resp. plaintext letter below by correspondence 
How many simple substitution ciphers exist for the alphabet?  \[25!\] 
Define \[\textit{key}\] for a simple substitution cipher  The associated encryption table 
Define \[\texit{cryptanalysis}\]  The process of decrypting a message without knowing the underlying key 
Define \[\textit{symmetric ciphers}\]  Alice and Bob both share the knowledge of the secret key \(k\) 