I dont understand this question at all what is it trying to tell me:
The meet-in-the-middle attack means that two successive encryptions using two different k bit keys do not give the security against a brute-force attack that you would expect from a 2k bit key. Blockquote
Consider the situation when using two successive AES encryptions. Calculate the complexity of a meet-in-the-middle attack in terms of the key size k (Use big-O notation). Assume that a 2-DES attack required you to build tables containing the “middle” values. Making simple assumptions, what is the size of these two tables? Show your working. Blockquote
In the meet-in-the-middle attack, if we built the tables first and then looked for matches, we would have another high complexity problem. For each of the table 1 entries, compare with all the table 2 entries; this algorithm has complexity of O(22k). Explain how the matching could be done while building the tables, resulting in the total complexity remaining at O(2k+1).