lsb隐写,密码为图片里万物皆空 无欲无求的首字母
wwjkwywq
# _*_ coding:utf-8 _*_
ip = (58, 50, 42, 34, 26, 18, 10, 2,
60, 52, 44, 36, 28, 20, 12, 4,
62, 54, 46, 38, 30, 22, 14, 6,
64, 56, 48, 40, 32, 24, 16, 8,
57, 49, 41, 33, 25, 17, 9, 1,
59, 51, 43, 35, 27, 19, 11, 3,
61, 53, 45, 37, 29, 21, 13, 5,
63, 55, 47, 39, 31, 23, 15, 7)
ip_1 = (40, 8, 48, 16, 56, 24, 64, 32,
39, 7, 47, 15, 55, 23, 63, 31,
38, 6, 46, 14, 54, 22, 62, 30,
37, 5, 45, 13, 53, 21, 61, 29,
36, 4, 44, 12, 52, 20, 60, 28,
35, 3, 43, 11, 51, 19, 59, 27,
34, 2, 42, 10, 50, 18, 58, 26,
33, 1, 41, 9, 49, 17, 57, 25)
e = (32, 1, 2, 3, 4, 5, 4, 5,
6, 7, 8, 9, 8, 9, 10, 11,
12, 13, 12, 13, 14, 15, 16, 17,
16, 17, 18, 19, 20, 21, 20, 21,
22, 23, 24, 25, 24, 25, 26, 27,
28, 29, 28, 29, 30, 31, 32, 1)
p = (16, 7, 20, 21, 29, 12, 28, 17,
1, 15, 23, 26, 5, 18, 31, 10,
2, 8, 24, 14, 32, 27, 3, 9,
19, 13, 30, 6, 22, 11, 4, 25)
s = [[[14, 4, 13, 1, 2, 15, 11, 8, 3, 10, 6, 12, 5, 9, 0, 7],
[0, 15, 7, 4, 14, 2, 13, 1, 10, 6, 12, 11, 9, 5, 3, 8],
[4, 1, 14, 8, 13, 6, 2, 11, 15, 12, 9, 7, 3, 10, 5, 0],
[15, 12, 8, 2, 4, 9, 1, 7, 5, 11, 3, 14, 10, 0, 6, 13]],
[[15, 1, 8, 14, 6, 11, 3, 4, 9, 7, 2, 13, 12, 0, 5, 10],
[3, 13, 4, 7, 15, 2, 8, 14, 12, 0, 1, 10, 6, 9, 11, 5],
[0, 14, 7, 11, 10, 4, 13, 1, 5, 8, 12, 6, 9, 3, 2, 15],
[13, 8, 10, 1, 3, 15, 4, 2, 11, 6, 7, 12, 0, 5, 14, 9]],
[[10, 0, 9, 14, 6, 3, 15, 5, 1, 13, 12, 7, 11, 4, 2, 8],
[13, 7, 0, 9, 3, 4, 6, 10, 2, 8, 5, 14, 12, 11, 15, 1],
[13, 6, 4, 9, 8, 15, 3, 0, 11, 1, 2, 12, 5, 10, 14, 7],
[1, 10, 13, 0, 6, 9, 8, 7, 4, 15, 14, 3, 11, 5, 2, 12]],
[[7, 13, 14, 3, 0, 6, 9, 10, 1, 2, 8, 5, 11, 12, 4, 15],
[13, 8, 11, 5, 6, 15, 0, 3, 4, 7, 2, 12, 1, 10, 14, 9],
[10, 6, 9, 0, 12, 11, 7, 13, 15, 1, 3, 14, 5, 2, 8, 4],
[3, 15, 0, 6, 10, 1, 13, 8, 9, 4, 5, 11, 12, 7, 2, 14]],
[[2, 12, 4, 1, 7, 10, 11, 6, 8, 5, 3, 15, 13, 0, 14, 9],
[14, 11, 2, 12, 4, 7, 13, 1, 5, 0, 15, 10, 3, 9, 8, 6],
[4, 2, 1, 11, 10, 13, 7, 8, 15, 9, 12, 5, 6, 3, 0, 14],
[11, 8, 12, 7, 1, 14, 2, 13, 6, 15, 0, 9, 10, 4, 5, 3]],
[[12, 1, 10, 15, 9, 2, 6, 8, 0, 13, 3, 4, 14, 7, 5, 11],
[10, 15, 4, 2, 7, 12, 9, 5, 6, 1, 13, 14, 0, 11, 3, 8],
[9, 14, 15, 5, 2, 8, 12, 3, 7, 0, 4, 10, 1, 13, 11, 6],
[4, 3, 2, 12, 9, 5, 15, 10, 11, 14, 1, 7, 6, 0, 8, 13]],
[[4, 11, 2, 14, 15, 0, 8, 13, 3, 12, 9, 7, 5, 10, 6, 1],
[13, 0, 11, 7, 4, 9, 1, 10, 14, 3, 5, 12, 2, 15, 8, 6],
[1, 4, 11, 13, 12, 3, 7, 14, 10, 15, 6, 8, 0, 5, 9, 2],
[6, 11, 13, 8, 1, 4, 10, 7, 9, 5, 0, 15, 14, 2, 3, 12]],
[[13, 2, 8, 4, 6, 15, 11, 1, 10, 9, 3, 14, 5, 0, 12, 7],
[1, 15, 13, 8, 10, 3, 7, 4, 12, 5, 6, 11, 0, 14, 9, 2],
[7, 11, 4, 1, 9, 12, 14, 2, 0, 6, 10, 13, 15, 3, 5, 8],
[2, 1, 14, 7, 4, 10, 8, 13, 15, 12, 9, 0, 3, 5, 6, 11]]]
pc1 = (57, 49, 41, 33, 25, 17, 9,
1, 58, 50, 42, 34, 26, 18,
10, 2, 59, 51, 43, 35, 27,
19, 11, 3, 60, 52, 44, 36,
63, 55, 47, 39, 31, 23, 15,
7, 62, 54, 46, 38, 30, 22,
14, 6, 61, 53, 45, 37, 29,
21, 13, 5, 28, 20, 12, 4)
pc2 = (14, 17, 11, 24, 1, 5, 3, 28,
15, 6, 21, 10, 23, 19, 12, 4,
26, 8, 16, 7, 27, 20, 13, 2,
41, 52, 31, 37, 47, 55, 30, 40,
51, 45, 33, 48, 44, 49, 39, 56,
34, 53, 46, 42, 50, 36, 29, 32)
d = (1, 1, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 1)
__all__ = ['desdecode']
class DES:
"""解密函数，DES加密与解密的方法相差不大
只是在解密的时候所用的子密钥与加密的子密钥相反
"""
def __init__(self):
pass
def decode(self, string, key, key_len, string_len):
output = ""
num = 0
# 将密文转换为二进制
code_string = self._functionCharToA(string, string_len)
# 获取字密钥
code_key = self._getkey(key, key_len)
# 如果密钥长度不是16的整数倍则以增加0的方式变为16的整数倍
real_len = (key_len / 16) + 1 if key_len % 16 != 0 else key_len / 16
trun_len = string_len * 4
# 对每64位进行一次加密
for i in range(0, trun_len, 64):
run_code = code_string[i:i + 64]
run_key = code_key[int(num % real_len)]
# 64位明文初始置换
run_code = self._codefirstchange(run_code)
# 16次迭代
for j in range(16):
code_r = run_code[32:64]
code_l = run_code[0:32]
# 64左右交换
run_code = code_r
# 右边32位扩展置换
code_r = self._functionE(code_r)
# 获取本轮子密钥
key_y = run_key[15 - j]
# 异或
code_r = self._codeyihuo(code_r, key_y)
# S盒代替/选择
code_r = self._functionS(code_r)
# P转换
code_r = self._functionP(code_r)
# 异或
code_r = self._codeyihuo(code_l, code_r)
run_code += code_r
num += 1
# 32互换
code_r = run_code[32:64]
code_l = run_code[0:32]
run_code = code_r + code_l
# 将二进制转换为16进制、逆初始置换
output += self._functionCodeChange(run_code)
return output
# 获取子密钥
def _getkey(self, key, key_len):
# 将密钥转换为二进制
code_key = self._functionCharToA(key, key_len)
a = [''] * 16
real_len = (key_len / 16) * 16 + 16 if key_len % 16 != 0 else key_len
b = [''] * int(real_len / 16)
for i in range(int(real_len / 16)):
b[i] = a[:]
num = 0
trun_len = 4 * key_len
for i in range(0, trun_len, 64):
run_key = code_key[i:i + 64]
run_key = self._keyfirstchange(run_key)
for j in range(16):
key_l = run_key[0:28]
key_r = run_key[28:56]
key_l = key_l[d[j]:28] + key_l[0:d[j]]
key_r = key_r[d[j]:28] + key_r[0:d[j]]
run_key = key_l + key_r
key_y = self._functionKeySecondChange(run_key)
b[num][j] = key_y[:]
num += 1
return b
# 异或
def _codeyihuo(self, code, key):
code_len = len(key)
return_list = ''
for i in range(code_len):
if code[i] == key[i]:
return_list += '0'
else:
return_list += '1'
return return_list
# 密文或明文初始置换
def _codefirstchange(self, code):
changed_code = ''
for i in range(64):
changed_code += code[ip[i] - 1]
return changed_code
# 密钥初始置换
def _keyfirstchange(self, key):
changed_key = ''
for i in range(56):
changed_key += key[pc1[i] - 1]
return changed_key
# 逆初始置换
def _functionCodeChange(self, code):
return_list = ''
for i in range(16):
list = ''
for j in range(4):
list += code[ip_1[i * 4 + j] - 1]
return_list += "%x" % int(list, 2)
return return_list
# 扩展置换
def _functionE(self, code):
return_list = ''
for i in range(48):
return_list += code[e[i] - 1]
return return_list
# 置换P
def _functionP(self, code):
return_list = ''
for i in range(32):
return_list += code[p[i] - 1]
return return_list
# S盒代替选择置换
def _functionS(self, key):
return_list = ''
for i in range(8):
row = int(str(key[i * 6]) + str(key[i * 6 + 5]), 2)
raw = int(str(key[i * 6 + 1]) + str(key[i * 6 + 2]) + str(key[i * 6 + 3]) + str(key[i * 6 + 4]), 2)
return_list += self._functionTos(s[i][row][raw], 4)
return return_list
# 密钥置换选择2
def _functionKeySecondChange(self, key):
return_list = ''
for i in range(48):
return_list += key[pc2[i] - 1]
return return_list
# 将十六进制转换为二进制字符串
def _functionCharToA(self, code, lens):
return_code = ''
lens = lens % 16
for key in code:
code_ord = int(key, 16)
return_code += self._functionTos(code_ord, 4)
if lens != 0:
return_code += '0' * (16 - lens) * 4
return return_code
# 二进制转换
def _functionTos(self, o, lens):
return_code = ''
for i in range(lens):
return_code = str(o >> i & 1) + return_code
return return_code
# 将unicode字符转换为16进制
def tohex(string):
return_string = ''
for i in string:
return_string += "%02x" % ord(i)
return return_string
def tounicode(string):
return_string = ''
string_len = len(string)
for i in range(0, string_len, 2):
return_string += chr(int(string[i:i + 2], 16))
return return_string
# 入口函数
def desdecode(from_code, key):
key = tohex(key)
des = DES()
key_len = len(key)
string_len = len(from_code)
if string_len % 16 != 0:
return False
if string_len < 1 or key_len < 1:
return False
key_code = des.decode(from_code, key, key_len, string_len)
return tounicode(key_code)
# 测试
if __name__ == '__main__':
print(desdecode('e3fab29a43a70ca72162a132df6ab532535278834e11e6706c61a1a7cefc402c8ecaf601d00eee72', 'mtqVwD4JNRjw3bkT9sQ0RYcZaKShU4sf'))QCTF{eCy0AALMDH9rLoBnWnTigXpYPkgU0sU4}