Steganalysis/F3.py

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2021-12-30 11:48:37 +00:00
# -*- coding: utf-8 -*-
"""
Created on Mon Jun 10 17:30:40 2019
@author: Administrator
"""
from Jsteg import Jsteg
class F3(Jsteg):
def __init__(self):
Jsteg.__init__(self)
def set_sequence_after_dct(self,sequence_after_dct):
self.sequence_after_dct=sequence_after_dct
sum_len=len(self.sequence_after_dct)
zero_len=len([i for i in self.sequence_after_dct if i==0])
one_len=len([i for i in self.sequence_after_dct if i in (-1,1)])
self.available_info_len=sum_len-zero_len-one_len # 不是特别可靠
print ("Load>> 大约可嵌入",sum_len-zero_len-int(one_len/2),'bits')
print ("Load>> 最少可嵌入",self.available_info_len,'bits\n')
def _write(self,index,data):
origin=self.sequence_after_dct[index]
if origin == 0:
return False
elif origin in (-1,1) and data==0:
self.sequence_after_dct[index]=0
return False
lower_bit=origin%2
if lower_bit==data:
pass
elif origin>0:
self.sequence_after_dct[index]=origin-1
elif origin<0:
self.sequence_after_dct[index]=origin+1
return True
def _read(self,index):
if self.sequence_after_dct[index] != 0:
return self.sequence_after_dct[index]%2
else:
return None
if __name__=="__main__":
f3=F3()
# 写
sequence_after_dct=[-1,0,1]*100+[i for i in range(-7,500)]
f3.set_sequence_after_dct(sequence_after_dct)
info1=[0,1,0,1,1,0,1,0]
f3.write(info1)
# 读
sequence_after_dct2=f3.get_sequence_after_dct()
f3.set_sequence_after_dct(sequence_after_dct2)
info2=f3.read()
print (info2)