Reversible Fragile Watermarking Scheme for Relational Database Based on Prediction-Error Expansion

Algorithm 2

Watermark embedding.

(1)	Hp = HMAC (Ks ||h1 ||h2 ||…|| hµ || Ks)  //Hashing of primary key hash values
(2)	for each attribute Ajdo
(3)	Hj = HMAC (Hp ||t1.Aj||t2.Aj||…|| tµ.Aj|| Ks) //attribute hash
(4)	//Generate watermark bits
(5)	Wj = µ MSB (Hj) //Assume length (Hj) ≥ µ
(6)	//Encode bit
(7)	for each tuple tido
(8)	Encode_Bit (ti.Aj, Wj[i], hi)   //See Algorithm3
(9)	end for
(10)	end for