Cipher Question - Computer/Electrical Engineering

Using the extremely simplified ECB example of a substitution and transposition cipher given in the lecture on ciphers week 8, complete the following cipher rounds (be sure to use XOR, not OR). Supposing we begin with the plaintext byte: lower case s = 01110011 in ASCII binary as follows:

1. Show the next full substitution and transposition round using the information above if the next subkey is 1110:

3. Now, ignoring the previous round, say we are on the 16th round and we have the following plaintext byte in binary:

And if you have the following subkey 1010, complete the round:

4. What ASCII character does the above round finally represent: ______ 5. Briefly describe in a few paragraphs what DES is, and how it works (include S-boxes):

L1 L2 L3 L4 R1 R2 R3 R4 PlainText 0 1 1 1 0 0 1 1 L1 L2 L3 L4 R1 R2 R3 R4 PlainText 0 1 1 1 0 0 1 1