17. Implement the Tiny Encryption Algorithm (TEA).

a. Use your TEA algorithm to encrypt the 64-bit plaintext block

0x0123456789ABCDEF

using the 128-bit key

0xA56BABCD00000000FFFFFFFFABCDEF01.

Decrypt the resulting ciphertext and verify that you obtain the

original plaintext.

b. Using the key in part a, encrypt and decrypt the following message

using each of the three block cipher modes discussed in the text

(ECB mode, CBC mode, and CTR mode).

Four score and seven years ago our fathers brought forth

on this continent, a new nation, conceived in Liberty,

and dedicated to the proposition that all men are created

equal.