else
unknown
parent
81019bbaa7
commit
dd4bacf3ab
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@ -0,0 +1,3 @@
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version https://git-lfs.github.com/spec/v1
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oid sha256:e890b050800c2ba0f0dc1aab56519c0c43b5d20fca4908976ddd41505a0393af
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size 136
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@ -0,0 +1,3 @@
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version https://git-lfs.github.com/spec/v1
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oid sha256:19681c97997aaa6a0382b91bd62d71fd3ee85f5443597888acbcdf4f537187b7
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size 125
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@ -3,14 +3,45 @@ For each color channel of each pixel in an Image, modify the least significant b
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This changes the RGB value of the pixel by a usually-imperceptible amount.
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The first 32 bits (10.66 pixels) will be used to store the length of the Secret content in big endian.
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Then, the Secret's extension is stored. A null byte indicates the end of the extension. This section is of variable length.
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A file with no extension will still require that null byte. A file with an extension will require 1 byte per character.
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A file with no extension requires only that null byte. A file with an extension requires 1 additional byte per character.
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Each Image pixel holds 3 Secret bits, so the Image must have at least ((secretbytes * (8 / 3)) + 19) pixels
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An Image can hold ((3 * (pixels - 19)) / 8) Secret bytes.
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Smallest image possible = 16 pixels with 48 bit secret: 32 for header; 8 for null extension; 8 for data
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Each Image pixel holds 3 Secret bits, so the Image must have at least ((secretbytes * (8 / 3)) + 14) pixels
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An Image can hold ((3 * (pixels - 14)) / 8) Secret bytes.
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Usage:
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> 3bitspixel.py encode imagefilename.png secretfilename.ext
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> 3bitspixel.py decode lacedimagename.png
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Reference table for files with NO EXTENSION.
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For each extension character, subtract 1 byte from secret size
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pixels | example dimensions | Secret file size
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100 | 10 x 10 | 32 bytes
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400 | 20 x 20 | 144 bytes
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2,500 | 50 x 50 | 932 bytes
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10,000 | 100 x 100 | 3,744 bytes
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40,000 | 200 x 200 | 14,994 bytes
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25,000 | 500 x 500 | 93,744 bytes (91 kb)
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1,000,000 | 1,000 x 1,000 | 374,994 bytes (366 kb)
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4,000,000 | 2,000 x 2,000 | 1,499,994 bytes (1.43 mb)
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25,000,000 | 5,000 x 5,000 | 9,374,994 bytes (8.94 mb)
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100,000,000 | 10,000 x 10,000 | 37,499,994 bytes (35.7 mb)
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pixels | example dimensions | Secret file size
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100 | 10 x 10 | 32 bytes
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697 | 25 x 28 (700) | 256 bytes
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2,745 | 50 x 55 (2,750) | 1,024 bytes (1 kb)
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21,860 | 142 x 154 (21,868) | 8,192 bytes (8 kb)
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87,396 | 230 x 380 (87,400) | 32,768 bytes (32 kb)
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349,540 | 463 x 755 (349,565) | 131,072 bytes (128 kb)
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1,398,116 | 1146 x 1120 (1,398,120) | 524,288 bytes (512 kb)
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2,796,217 | 1621 x 1725 (2,796,225) | 1,048,576 bytes (1 mb)
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11,184,825 | 3500 x 3200 (11,200,000) | 4,194,304 bytes (4 mb)
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44,739,257 | 6700 x 6700 (44,890,000) | 16,777,216 bytes (16 mb)
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89,478,500 | 9500 x 9500 (90,250,000) | 33,554,432 bytes (32 mb)
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'''
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from PIL import Image
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import binascii
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@ -18,8 +49,8 @@ import math
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import os
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import sys
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# 11 for the content length, and AT LEAST 8 for the extension (which always ends in 1 null byte)
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HEADER_SIZE = 19
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# 11 for the content length
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HEADER_SIZE = 11
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class StegError(Exception):
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pass
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@ -44,6 +75,11 @@ def increment_pixel(save=True):
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pixel = list(image.getpixel( (pixel_index % image.size[0], pixel_index // image.size[0]) ))
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#print('opend', pixel)
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def bytes_to_pixels(bytes):
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return ((bytes * (8 / 3)) + 14)
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def pixels_to_bytes(pixels):
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return ((3 * (pixels - 14)) / 8)
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############## #### #### ######## ###### ########## ##############
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#### ## #### #### #### #### #### #### #### #### #### ##
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@ -62,6 +98,18 @@ def encode(imagefilename, secretfilename):
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pixel_index = 0
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channel_index = 0
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def modify_pixel(bit):
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global pixel
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global channel_index
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#print(channel_index, bit)
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#print(pixel_index, channel_index, bit)
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channel = pixel[channel_index]
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channel = binary(channel)[:7] + bit
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channel = int(channel, 2)
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pixel[channel_index] = channel
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#print(pixel)
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print('Hiding "%s" within "%s"' % (secretfilename, imagefilename))
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image = Image.open(imagefilename)
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@ -78,25 +126,13 @@ def encode(imagefilename, secretfilename):
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secret_extension = os.path.splitext(secretfilename)[1][1:]
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secret_content_length = (len(secret) * 8) + (len(secret_extension) * 8) + 8
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requiredpixels = math.ceil((secret_content_length / 3) + HEADER_SIZE)
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requiredpixels = math.ceil((secret_content_length + 32) / 3)
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if totalpixels < requiredpixels:
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raise StegError('Image does not have enough pixels to store the Secret'
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'Must have at least %d pixels' % requiredpixels)
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print('%d available pixels, %d required' % (totalpixels, requiredpixels))
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def modify_pixel(bit):
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global pixel
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global channel_index
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#print(channel_index, bit)
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#print(pixel_index, channel_index, bit)
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channel = pixel[channel_index]
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channel = binary(channel)[:7] + bit
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channel = int(channel, 2)
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pixel[channel_index] = channel
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#print(pixel)
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# --> YOU ARE HERE <--
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pixel = list(image.getpixel((0, 0)))
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Loading…
Reference in New Issue