Secure and Efficient Image Retrieval over Encrypted Cloud Data

Table 1

Average category entropy of each level.

Parameter	Level of the Index Tree
	1	2	3	4	5	6	7	8	9	10	11
0.2	2.99	2.49	2.1	1.75	1.38	1.07	0.81	0.62	0.44	0.21	0
0.3	3.2	2.82	2.07	1.81	1.43	1.18	0.91	0.7	0.48	0.24	0
0.4	3.32	2.88	2.28	1.8	1.53	1.28	1.02	0.78	0.54	0.28	0
0.5	3.32	3.03	2.31	1.83	1.56	1.27	1.03	0.79	0.55	0.3	0
0.6	3.32	2.91	2.37	1.96	1.65	1.41	1.11	0.89	0.61	0.32	0
0.7	3.32	2.6	2.1	1.71	1.46	1.24	1.03	0.81	0.57	0.29	0
0.8	3.32	2.92	2.32	1.85	1.52	1.26	1.04	0.81	0.57	0.3	0
0.9	3.32	2.92	2.25	1.78	1.49	1.27	1.03	0.83	0.58	0.3	0