Denote the des encryption of the plain text

Assignment Help Computer Network Security

Reference no: EM13186358

a) Let DES_k(P) denote the DES encryption of the plain text P by the key K.

i) If we set K to be the key consisting of all zeroes, explain why encrypting twice with this key for DES has the same effect as encrypting then decrypting. Equivalently, account for the following property when using the all-zero key

DES_k(DES_k(P) = P

ii) Find another key that also has this property, and explain the structure of the DES key schedule that permit such keys to exist.

b) Let b' denote the complement of a sequence of bits, so that for 780_DES encryption.png example. Then considering the round structure of DES, show that

In other words, complementing the key, plaintext and ciphertext produces the same ciphertext as when none of these values is complemented.Hint: Use the following property of the XOR function x + x = 0.

Reference no: EM13186358

Questions Cloud

Find the volume of the solid whose base is the region : Find the volume of the solid whose base is the region bounded by y=x^{6}, y=1, and the y-axis and whose cross-sections perpendicular to the y axis are equilateral triangles.

How many players were there : After winning the championships, all Detroit Pistons teammates exchanged "high-fives."Altogether there were 66 high-fives. How many players were there?

What happens to the price of u.s. goods in mexico : Why would a country (for example, China) choose to keep their currency relatively pegged to the U.S. dollar. If the U.S. dollar were to appreciate considerably against most currencies, what would be the effect on Chinese exports to countries othe..

What are the dimensions and maximum area : A rectangular is to be fenced off and divide in two by another fence parallel to one side of the playground. 720 feet of fencing is used. what are the dimensions and maximum area.

Denote the des encryption of the plain text : Find another key that also has this property, and explain the structure of the DES key schedule that permit such keys to exist.

Real gdp rose by what percent : Suppose nominal GDP in 2005 was $15 trillion, and in 2006 it was $16 trillion. The general price index in 2005 was 100, and in 2006 it was 103. Between 2005 and 2006, real GDP rose by what percent

What is the maximum voltage produced by the system : The electrical signal created by a piece of test equipment at a specific point in time is described by the function Vinst(t) = 12 × sin(360 × 60 × 6.3 + 79). What is the maximum voltage produced by the system.

What is the standard deviations : A factory employs several thousand workers, of whom 20% are Hispanic. If the 20 members of the union executive committee were chosen from the workers at random, the number of Hispanics on the committee would have the binomial distribution with n =..

A textile manufacturer concerned : A textile manufacturer concerned about its survival in the world marketplace has set as its goal, "To increase training and educational opportunities for its employees during the next twenty-four months." Why is this corporate objective ineffective

User Account

All Pages