HB⁺-MHT: Lightweight and Efficient Data Integrity Verification Scheme for Cloud Virtual Machines

Algorithm 1

Generation of HHT.

	Input: Fileinfoarray satisfying  = 1
	Output: Nodelist
	Begin
	For each item f in Fileinfoarray {
	//Initialization, each tree has only one root node
	HHTNode n = new HHTnode ();
	n.h = hash (f.data);
	n.weight = f.weight;
	n.lc = 0; n.rc = 0;
	n.lp = null; n.rp = null;
	Nodelist.equeue (n)
	}
	While (NodeList.size! = 1)
	//Select two trees with the smallest AWPL from the queue
	nl, nr ← min (NodeList);
	//Merge the two trees
	HHTNode n = new HHTnode();
	n.h = hash (nl.h || nr.h);
	n.weight = nl.weight + nr.weight;
	n.lc = nl.lc + nl.rc; n.rc = nr.lc + nr.rc;
	n.lp = nl; n.rp = nr;
	//Add a new binary tree to the queue
	Nodelist.equeue (n);
	//Delete the analyzed two subtrees
	Nodelist.deequeue (nl);
	Nodelist.deequeue (n2);
	end while
	return Nodelist
	end