Cryptography

1) Suppose you have the following 64-bit block: {1, 1, 0, 0, 0, 1, 1, 1, 0, 0, 0, 1, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 0, 0, 0, 1, 1, 0, 0, 1, 0, 0, 1, 0, 1, 1, 0, 1, 0, 0, 1, 0, 1, 1, 1, 0, 0, 0, 0, 1, 0, 0, 1, 0, 1, 1, 0, 1, 0, 1}. This 64-bit block is the input of the first round in DES, that is (L0,R0). What are the first 32 bits of the output of the first

round?

2) Suppose you have the following 64-bit block: {0, 1, 1, 0, 0, 1, 0, 0, 1, 0, 1, 1, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 0, 1, 1, 0, 0, 1, 1, 1, 0, 0, 1, 0, 0, 1, 0, 0, 0, 0, 1, 1, 1, 0, 1, 0, 0, 1, 1, 1, 0, 0, 0, 1, 1, 0, 0, 0, 0, 1, 0, 1, 0, 1}. This 64-bit block is the input of the second round in DES, that is (L1,R1). What are the first 32 bits of the output of the second round?

3) Suppose you have the following 64-bit block: {0, 0, 0, 1, 0, 1, 1, 1, 1, 0, 0, 1, 0, 0, 0, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 1, 0, 1, 0, 1, 0, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1, 1, 1, 0, 1, 1, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 0, 0, 1, 1, 1, 1, 0, 1}. This 64-bit block is the input of the first round in DES, that is (L0,R0). Suppose also that the output of the function "f" is the following 32-bit block: {0, 1, 0, 0, 1, 0, 0, 1, 0, 1, 0, 1, 0, 0, 0, 0, 1, 1, 1, 0, 1, 1, 1, 1, 1, 0, 0, 1, 1, 1, 0, 0} What is the output of the first round?

4) Suppose you have the following 64-bit block: {1, 1, 1, 1, 0, 1, 0, 0, 1, 1, 1, 1, 0, 1, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1, 1, 1, 0, 1, 0, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 0, 1, 0, 0, 1, 0, 1, 1, 0, 1, 0, 1, 0, 1, 1}. This 64-bit block is the input of the first round in DES, that is (L0,R0). Suppose also that the output of the function "f" is the following 32-bit block: {1, 1, 0, 1, 1, 1, 0, 1, 0, 0, 0, 1, 0, 1, 1, 1, 0, 1, 0, 1, 0, 0, 0, 0, 1, 0, 1, 1, 1, 1, 0, 0} What is the output of the first round?

6) What are the inputs of the "f" function?

Question 6 options:

a. The first 32 bits of the 64-bit block and a sub-key of 48 bits.

b. The first 48 bits of the 64-bit block and a sub-key of 32 bits.

c. The last 48 bits of the 64-bit block and a sub-key of 32 bits.

d. The last 32 bits of the 64-bit block and a sub-key of 48 bits.

e. The last 32 bits of the 64-bit block and a sub-key of 56 bits.

7) What is the output of the "f" function?

Question 7 options:

a. 32 bits

b. 48 bits

c. 56 bits

d. 16 bits

e. L0 bits

f. R0 bits

8) How many sub-keys are generated from the original key k?

Question 8 options:

a. 32

b. 16

c. 48

d. 64

e. 128

f. L0,R0

Question 4

 Consider the 32-bit block: {1, 1, 1, 0, 0, 1, 1, 1, 1, 0, 1, 0, 1, 1, 0, 1, 1, 1, 0, 1, 1, 0, 1, 0, 1, 0, 1, 0, 1, 1, 1, 1}.

Apply the permutation of the f-function to this 32-bit block.

Write the numbers separated with commas, leave one space after every comma. Do NOT use "{" or "}" in the answer.

 

Question 5

Consider the 32-bit block: {1, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 0, 0, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0}.

Apply the permutation of the f-function to this 32-bit block.

Write the numbers separated with commas, leave one space after every comma. Do NOT use "{" or "}" in the answer.