[英]python - Steganography - UnicodeDecode Error
我正在編寫一個Python腳本來隱藏圖像中的數據。 它基本上隱藏了.PNG中每個像素的RGB映射中紅色的最后兩位中的位。 該腳本適用於小寫字母,但會出現句號錯誤。 它產生此錯誤:
追溯(最近一次通話):文件“ E:\\ Python \\ Steganography \\ main.py”,行65,在打印中(取消隱藏('coded-img.png'))文件“ E:\\ Python \\ Steganography \\ main。 py”,第60行,在取消隱藏消息中= bin2str(binary)文件“ E:\\ Python \\ Steganography \\ main.py”,第16行,在bin2str中,返回n.to_bytes((n.bit_length()+ 7)// 8 ,'big')。decode()UnicodeDecodeError:'utf-8'編解碼器無法解碼位置6的字節0x80:無效的起始字節
這是我的代碼:
from PIL import Image
def str2bin(message):
binary = bin(int.from_bytes(message.encode('utf-8'), 'big'))
return binary[2:]
def bin2str(binary):
n = int(binary, 2)
return n.to_bytes((n.bit_length() + 7) // 8, 'big').decode()
def hide(filename, message):
image = Image.open(filename)
binary = str2bin(message) + '00000000'
data = list(image.getdata())
newData = []
index = 0
for pixel in data:
if index < len(binary):
pixel = list(pixel)
pixel[0] >>= 2
pixel[0] <<= 2
pixel[0] += int('0b' + binary[index:index+2], 2)
pixel = tuple(pixel)
index += 2
newData.append(pixel)
print(binary)
image.putdata(newData)
image.save('coded-'+filename, 'PNG')
def unhide(filename):
image = Image.open(filename)
data = image.getdata()
binary = '0'
index = 0
while binary[-8:] != '00000000':
binary += bin(data[index][0])[-2:]
index += 1
binary = binary[:-1]
print(binary)
print(index*2)
message = bin2str(binary)
return message
hide('img.png', 'alpha.')
print(unhide('coded-img.png'))
請幫忙。 謝謝!
您的代碼至少存在兩個問題。
第一個問題是您的編碼可能會錯位1位,因為bin()
函數的輸出中不包括前導空位:
>>> bin(int.from_bytes('a'.encode('utf-8'), 'big'))[2:]
'1100001'
# This string is of odd length and (when joined with the terminating '00000000')
# turns into a still odd-length '110000100000000' which is then handled by your
# code as if there was an extra trailing zero (so that the length is even).
# During decoding you compensate for that effect with the
#
# binary = binary[:-1]
#
# line. The latter is responsible for your stated problem when the binary
# representation of your string is in fact of even length and doesn't need
# the extra bit as in the below example:
>>> bin(int.from_bytes('.'.encode('utf-8'), 'big'))[2:]
'101110'
您最好在前面加上一個額外的空位(如果需要),將二進制字符串補充為偶數長度。
另一個問題是,在恢復隱藏消息的同時,可以通過將一個(部分恢復的)符號的前導位與另一符號的尾隨級聯來提前滿足停止條件binary[-8:] == '00000000'
。 例如,在以下情況下可能會發生這種情況
符號@ (ASCII碼= 64,即未設置6個低階位),后跟任何ASCII碼值小於64(即未設置2個高階位)的字符;
一個空格字符(ASCII碼= 32,即未設置4個低位),后跟換行符/換行符(ASCII碼= 10,即未設置4個高位)。
您可以通過要求在最后8位都未設置時對一個完整字節進行解碼來解決該錯誤:
while not (len(binary) % 8 == 0 and binary[-8:] == '00000000'):
# ...
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