Gray-scale encryption of image encryption: An example of a round of encryption algorithm based on the key × decryption key ≡ 1 mod gray level-lena diagram

  For the algorithm principle and implementation, please refer to the blog post "Gray Encryption of Image Encryption: Principle and Steps of Modular Gray Level Encryption Algorithm"

Original image (lena.png, gray level 256, size $256\times 256$）

Different ppEncryption effect corresponding to$p$ value

p=1	p=3	p=5	p=7
p=9	p=11	p=13	p=15
p=17	p=19	p=21	p=23
p=25	p=27	p=29	p=31
p=33	p=35	p=37	p=39
p=41	p=43	p=45	p=47
p=49	p=51	p=53	p=55
p=57	p=59	p=61	p=63
p=65	p=67	p=69	p=71
p=73	p=75	p=77	p=79
p=81	p=83	p=85	p=87
p=89	p=91	p=93	p=95
p=97	p=99	p=101	p=103
p=105	p=107	p=109	p=111
p=113	p=115	p=117	p=119
p=121	p=123	p=125	p=127
p=129	p=131	p=133	p=135
p=137	p=139	p=141	p=143
p=145	p=147	p=149	p=151
p=153	p=155	p=157	p=159
p=161	p=163	p=165	p=167
p=169	p=171	p=173	p=175
p=177	p=179	p=181	p=183
p=185	p=187	p=189	p=191
p=193	p=195	p=197	p=199
p=201	p=203	p=205	p=207
p=209	p=211	p=213	p=215
p=217	p=219	p=221	p=223
p=225	p=227	p=229	p=231
p=233	p=235	p=237	p=239
p=241	p=243	p=245	p=247
p=249	p=251	p=253	p=255