Given an oracle AESk that can accept binary strings and produce

encryptions based on the AES cryptosystem using the secret key k$.$

$1.$ Describe an algorithm by which you can find the block size using the

oracle.

$2.$ Describe an algorithm with which you can see if oracle uses ECB mode.

$3.$ Describe an algorithm that can decrypt any message

has been produced by AESk in ECB mode. For this purpose you can use the

AESk and generate message ciphers of your choice. $($Hint take advantage

that you can find out the block size$).$ What is the complexity of your algorithm if the

block length is l bits