The parts of a symmetric block cipher's hardware can be summed up as follows. How does it work, and what are the key distinctions between its two primary varieties?

To what extent may and why are keys shared across block and stream ciphers?

What is the difference between a block cipher and a stream cipher? What is the difference between an unconditionally secure cipher and a computationally secure cipher?   What is the difference between a monoalphabetic cipher and a polyalphabetic cipher?  Why is it important to study Feistel ciphers?

Comparing cypher block chaining to cypher feedback mode in terms of the number of encryption operations necessary to transport a large file, cypher block chaining is more efficient than cypher feedback mode. Which one is more efficient, and how much more so?

Describe the steps involved in mounting a statistical attack on a monoalphabetic substitution cipher. (please do not explain it with pictures) Explain why this approach would fail on a polyalphabetic substitution cipher?

How may block and stream ciphers exchange keys, and why should they be different?

How may block and stream ciphers exchange keys, and why should they be different?

Describe the process of how to solve the substitution cipher below and solve it: ZFSZB YESUK SQYDJ SQGVK SGZBJ WBSWG IZXWF UVDYZ TZVKW JJSUQ JJTDQ KCSPI QKQFP FZYBW FPWFU QYWIC SYZFW Y

As one may have anticipated, the Feistel cypher design is, in fact, a cypher. It's worth looking at current block ciphers based on the Feistel network?

Note: The notation from this problem is from Understanding Cryptography by Paar and Pelzi. Suppose you have an LFSR with 6 state bits. The first 12 bits of output produced by this LFSR are 101011100010 = 80818283848586878889810811- The first bit produced is the leftmost bit and the bit most recently produced is the rightmost bit. a) What is the initial state of the LFSR? Please enter your answer as unspaced binary digits (e.g. 010101 to represent 85 = 0, $4 = 1, 83 = 0, 82 = 1, 81 = 0, 80 = 1). b) What are the tap bits of the LFSR? Please enter your answer as unspaced binary digits (e.g. 010101 to represent p = 0, P₁ = 1, P3 = 0, P2 = 1, P₁ = 0, Po = 1).