QUIZ BANK WITH EDITED AND TESTED ANSWERS C839 - INTRODUCTION TO CRYPTOGRAPHY QUESTIONS WITH 2026-2027 20pages

Block Size: 128 bits Key Size: 128, 192, or 256 bits Rounds: 32 Network: Substitution-Permutation Tiny Encryption Algorithm (TEA) : Symmetric Block Cipher Block Size: 64 bits Key Size: 128 bits Cryptography : Deciphering secret writings, kryptos means hidden and grafo means write. Must not be readable by interlopers over secure/hidden communications. Readable by intended recipients only. Mono-Alphabet Substitution Algorithms : Include Ceasar, Atbash, Affine and ROT13 Caeser Cipher : Is one of the oldest methods, was used by ancient Romans. Shift of letter. Easy to crack to common words like "A" and "The". Single Substitution Weakness : Using common words (A, THE, OO, EE) in English Lang to brute force single substitution ciphers. Null Cipher : Hidden message in unrelated text • The sender and recipient have prearranged to use some pattern, taking certain letters from the message. Book Cipher : Parties agree on a particular book. Simplest implementation to send coordinates for words Rail Fence Cipher : Widely known Transposition cipher. Plaintext written in columns and transposed in rows. Recipient reconstructs the original message Symmetric Key Cryptography uses two processes : Substitution (XOR the PT with key) and transposition (swapping blocks of text) DES (Data Encryption Standard) : Symmetric Block Cipher Block Size: 64 bit Key Size: 56 bit Rounds: 16 rounds