-
Notifications
You must be signed in to change notification settings - Fork 0
/
EZStego隐写.py
109 lines (90 loc) · 3.14 KB
/
EZStego隐写.py
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
from PIL import Image
import numpy as np
import math
"""
假设调色板索引为
0 1 2 3 4 5 6 7
假设亮度序号(Y_index)为
index: 0 1 2 3 4 5 6 7
2 5 4 1 7 3 6 0
则
# Y_index_inverse
index: 0 1 2 3 4 5 6 7
7 3 0 5 2 1 6 4
# 例子
载体 [3 0 6 4] ; 待嵌入信息 0110
嵌入：[3 0 6 4]=>[5 7 6 2]=>(by 0110) [4 7 7 2]=>[7 0 0 4]
结果：[3 0 6 4]=>(by 0110)=>[7 0 0 4]
提取：[7 0 0 4]=>[4 7 7 2]=>0110
"""
class GIF_Steg:
def __init__(self):
self.im = None
def load_gif(self, gif_file):
self.im = Image.open(gif_file)
self._load_palette()
self._sort_palette()
self._load_palette_data()
self.available_info_len = len(self.palette_data)
def write(self, info):
info = self._set_info_len(info)
self.palette_data = self._write(self.palette_data, info)
def read(self):
_len, im_index = self._get_info_len()
info = self._read(self.palette_data[im_index:im_index + _len])
return info
def save(self, filename):
self.im.save(filename)
# ==========================================#
def _load_palette(self):
self.palette = []
palette = self.im.palette.palette
for i in range(int(len(palette) / 3)):
self.palette.append((palette[3 * i], palette[3 * i + 1], palette[3 * i + 2]))
def _sort_palette(self):
f = lambda t: 0.299 * t[0] + 0.587 * t[1] + 0.114 * t[2]
Y = [f(t) for t in self.palette]
self.Y_index = np.argsort(Y)
self.Y_index_inverse = [0] * 256
for i in range(len(self.Y_index)):
self.Y_index_inverse[self.Y_index[i]] = i
def _load_palette_data(self):
self.palette_data = self.im.getpalette()
def _set_info_len(self, info):
l = int(math.log(self.available_info_len, 2)) + 1
info_len = [0] * l
_len = len(info)
info_len[-len(bin(_len)) + 2:] = [int(i) for i in bin(_len)[2:]]
return info_len + info
def _get_info_len(self):
l = int(math.log(self.available_info_len, 2)) + 1
len_list = []
for i in range(l):
_d = self._get_lsb(self.palette_data[i])
len_list.append(str(_d))
_len = ''.join(len_list)
_len = int(_len, 2)
return _len, l
def _write(self, palette_data, info):
for i in range(len(info)):
Y_index = self.Y_index_inverse[palette_data[i]]
lower_bit = Y_index % 2
if lower_bit == info[i]:
pass
elif (lower_bit, info[i]) == (0, 1):
palette_data[i] = self.Y_index[Y_index + 1]
elif (lower_bit, info[i]) == (1, 0):
palette_data[i] = self.Y_index[Y_index - 1]
return palette_data
def _read(self, palette_data):
info = []
for i in range(len(palette_data)):
info.append(self._get_lsb(palette_data[i]))
return info
def _get_lsb(self, _palette_data):
return self.Y_index_inverse[_palette_data] % 2
if __name__ == "__main__":
gs = GIF_Steg()
gs.load_gif('1.gif')
gs.write([0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 1])
print(gs.read())