Privacy Protection of Social Networks Based on Classified Attribute Encryption

Algorithm 1

Generates re-encryption key.

	Input: the set of leaf node attributes of the access tree
	Output: new key
	//Generate a new key for each leaf node
(1)	if (i ∉ URL)
	exit;
(2)	else
(3)	take any s’ ∈ Z;
(4)	for z ∈ Z, generate a new set of leaf node attributes
(5)	compute new private key of leaf node;
(6)	take any  ∈ Zp;
(7)	calculate the re-encryption key according to the new access tree; //Generate a new key
(8)	replace the new key PPK’;
(9)	replace a new signature;
(10)	=  //Compute new public parameters