像素是图像的组成部分。
每个像素包含三个值:(红色、绿色、蓝色)也称为 RGB 值。
每个 RGB 值的范围从 0 到 255。
对于数据中的每个字符,将其 ASCII 值转换为 8 位二进制 [1]。
一次读取三个像素,其总 RGB 值为 3*3=9 个。前八个 RGB 值用于存储一个转换为 8 位二进制的字符。
比较相应的RGB值和二进制数据。如果二进制数字为 1,则 RGB 值将转换为奇数,否则为偶数。
第 9 个值确定是否应该读取更多像素。如果有更多数据要读取,即编码或解码,则第 9 个像素变为偶数;否则,如果我们想停止进一步读取像素,那就让它变得奇数。
假设要隐藏的消息是‘Hii’。
[(27, 64, 164), (248, 244, 194), (174, 246, 250), (149, 95, 232),
(188, 156, 169), (71, 167, 127), (132, 173, 97), (113, 69, 206),
(255, 29, 213), (53, 153, 220), (246, 225, 229), (142, 82, 175)]
(27, 64, 164), (248, 244, 194), (174, 246, 250)
(26, 63, 164), (248, 243, 194), (174, 246, 250)
[(26, 63, 164), (248, 243, 194), (174, 246, 250), (148, 95, 231),
(188, 155, 168), (70, 167, 126), (132, 173, 97), (112, 69, 206),
(254, 29, 213), (53, 153, 220), (246, 225, 229), (142, 82, 175)]
同样,一次读取三个像素。前 8 个 RGB 值为我们提供了有关机密数据的信息,第 9 个值告诉我们是否继续前进。
对于前八个值,如果值为奇数,则二进制位为 1 ,否则为 0 。
这些位连接成一个字符串,每三个像素,我们得到一个字节的秘密数据,这意味着一个字符。
现在,如果第 9 个值是偶数,那么我们继续一次读取三个像素,否则,我们停止。
[(26, 63, 164), (248, 243, 194), (174, 246, 250), (148, 95, 231),
(188, 155, 168), (70, 167, 126), (132, 173, 97), (112, 69, 206),
(254, 29, 213), (53, 153, 220), (246, 225, 229), (142, 82, 175)]
[(26, 63, 164), (248, 243, 194), (174, 246, 250)
# Python program implementing Image Steganography
# PIL module is used to extract
# pixels of image and modify it
from PIL import Image
# Convert encoding data into 8-bit binary
# form using ASCII value of characters
def genData(data):
# list of binary codes
# of given data
newd = []
for i in data:
newd.append(format(ord(i), '08b'))
return newd
# Pixels are modified according to the
# 8-bit binary data and finally returned
def modPix(pix, data):
datalist = genData(data)
lendata = len(datalist)
imdata = iter(pix)
for i in range(lendata):
# Extracting 3 pixels at a time
pix = [value for value in imdata.__next__()[:3] +
imdata.__next__()[:3] +
imdata.__next__()[:3]]
# Pixel value should be made
# odd for 1 and even for 0
for j in range(0, 8):
if (datalist[i][j] == '0' and pix[j]% 2 != 0):
pix[j] -= 1
elif (datalist[i][j] == '1' and pix[j] % 2 == 0):
if(pix[j] != 0):
pix[j] -= 1
else:
pix[j] += 1
# pix[j] -= 1
# Eighth pixel of every set tells
# whether to stop ot read further.
# 0 means keep reading; 1 means thec
# message is over.
if (i == lendata - 1):
if (pix[-1] % 2 == 0):
if(pix[-1] != 0):
pix[-1] -= 1
else:
pix[-1] += 1
else:
if (pix[-1] % 2 != 0):
pix[-1] -= 1
pix = tuple(pix)
yield pix[0:3]
yield pix[3:6]
yield pix[6:9]
def encode_enc(newimg, data):
w = newimg.size[0]
(x, y) = (0, 0)
for pixel in modPix(newimg.getdata(), data):
# Putting modified pixels in the new image
newimg.putpixel((x, y), pixel)
if (x == w - 1):
x = 0
y += 1
else:
x += 1
# Encode data into image
def encode():
img = input("Enter image name(with extension) : ")
image = Image.open(img, 'r')
data = input("Enter data to be encoded : ")
if (len(data) == 0):
raise ValueError('Data is empty')
newimg = image.copy()
encode_enc(newimg, data)
new_img_name = input("Enter the name of new image(with extension) : ")
newimg.save(new_img_name, str(new_img_name.split(".")[1].upper()))
# Decode the data in the image
def decode():
img = input("Enter image name(with extension) : ")
image = Image.open(img, 'r')
data = ''
imgdata = iter(image.getdata())
while (True):
pixels = [value for value in imgdata.__next__()[:3] +
imgdata.__next__()[:3] +
imgdata.__next__()[:3]]
# string of binary data
binstr = ''
for i in pixels[:8]:
if (i % 2 == 0):
binstr += '0'
else:
binstr += '1'
data += chr(int(binstr, 2))
if (pixels[-1] % 2 != 0):
return data
# Main Function
def main():
a = int(input(":: Welcome to Steganography ::\n"
"1. Encode\n2. Decode\n"))
if (a == 1):
encode()
elif (a == 2):
print("Decoded Word : " + decode())
else:
raise Exception("Enter correct input")
# Driver Code
if __name__ == '__main__' :
# Calling main function
main()
https://www.geeksforgeeks.org/program-decimal-binary-conversion/
https://www.geeksforgeeks.org/working-images-python/
https://dev.to/erikwhiting88/let-s-hide-a-secret-message-in-an-image-with-python-and-opencv-1jf5
A code along with the dependencies can be found here:https://github.com/goelashwin36/image-steganography
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