DES uses a key schedule that generates $16$ round keys from a $56-$bit key. Certain weak keys are known

to result in security vulnerabilities.

Question:

$1.$ Describe the key scheduling process in DES. How are the $16$ subkeys generated from the

original key?

$2.$ Given the following $56-$bit key in hexadecimal:

$0123456789$ABCDEF

Perform the key scheduling process and generate all $16$ round keys.

$3.$ Research and identify weak keys in DES. Explain why these weak keys are problematic for DES

security. Provide an example of a weak key and demonstrate how it compromises the encryption process.