Encryption algorithm

1. It is possible to use a hash function to construct a block cipher with a structure similar to DES. Because a hash function is one way and a block cipher must be reversible (to decrypt), how is it possible?

2. Now consider the opposite problem: Use an encryption algorithm to construct a oneway hash function. Consider using RSA with a known key. Then process a message consisting of a sequence of blocks as follows: Encrypt the first block, XOR the result with the second block and encrypt again, and so on. Show that this scheme is not secure by solving the following problem. Given a two-block message B1, B2, and its hash, we have

Don't use plagiarized sources. Get Your Custom Essay on
Encryption algorithm
Just from $13/Page
Order Essay

RSAH(B1, B2) = RSA(RSA(B1) ⊕ B2)

Given an arbitrary block C1, choose C2 so that RSAH(C1, C2) = RSAH(B1, B2). Thus, the hash function does not satisfy weak collision resistance.

Place Order
Grab A 14% Discount on This Paper
Pages (550 words)
Approximate price: -
Paper format
  • 275 words per page
  • 12 pt Arial/Times New Roman
  • Double line spacing
  • Any citation style (APA, MLA, Chicago/Turabian, Harvard)

Try it now!

Grab A 14% Discount on This Paper

Total price:

How it works?

Follow these simple steps to get your paper done

Place your order

Fill in the order form and provide all details of your assignment.

Proceed with the payment

Choose the payment system that suits you most.

Receive the final file

Once your paper is ready, we will email it to you.