Question

Problem 1: Forging a blockwise MAC We saw in class that vanilla AES is an unforgeable message authentication code (MAC).. as long as each message is only one block long. In this problem, your task is to forge a MAC when we apply AES separately to each block (separately) of long messages. Below, I include three messages in ASCII along with their blockwise AES encipherings in hex. You don't know the key. ai = ‘Deposit amount: 5 dollars, ti = fde1b66f2f85736048d35408c5ef5e12af0861635d 192 138dc36d9c775e4e98a a2 = 'One million dolls is quite the collection, ab208adcBd1374cf1b297c11873c9o9 fc031582e844c7dc36fffa86148254 41088ffda736ae33287896ce08f3d8ec7bf a3 = 'Hey nice binoculars, t3-8649 171fefd1662370a2b482c8d39e5d 16e10fedac2a10109f18b08358eaab54 Your task: Forge the tag corresponding to the message 'Deposit amount: One million dollars'. Your output: The resulting tag, hex-encoded with lowercase letters. SHA-256 hash of the output: cf270b02bfc8dd05df220db9ea459a2c3ea50b9a8eedc06a3b6c952ee39f7aa7

Answer 1

Input Text:Deposit Amount: 'One million dollars'

The SHA256 Hash generated is: 62d94c67cb9188bc0fb98c92508f594f426bfe090c86e6df4c936900e00ee9fb

Please let me know in case of any clarifications required. Thanks!