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| from PIL import Image
from decimal import *
import numpy as np
import random
getcontext().prec = 20
def f1(x):
# It is based on logistic map in chaotic systems
# The parameter r takes the largest legal value
mu = 4
x = mu * x * (1 - x)
return x
def f2(x):
# same as f1
mu = 4
x = mu * x * (1 - x)
return x
def f3(x):
# same as f1
mu = 4
x = mu * x * (1 - x)
return x
def encryptImage(path):
im = Image.open(path)
size = im.size
pic = np.array(im)
im.close()
r1 = Decimal('0.478706063089473894123')
r2 = Decimal('0.613494245341234672318')
r3 = Decimal('0.946365754637812381837')
w,h = size
for i in range(200):
r1 = f1(r1)
r2 = f2(r2)
r3 = f3(r3)
const = 10**14
replace_list = list()
for x in range(w):
for y in range(h):
x1 = int(round(const*r1))%w
y1 = int(round(const*r2))%h
r1 = f1(r1)
r2 = f2(r2)
tmp = pic[y,x]
pic[y,x] = pic[y1,x1]
pic[y1,x1] = tmp
replace_list.append([(y,x),(y1,x1)])
f = open('test.txt','a')
f.write(str(replace_list))
p0 = random.randint(100,104)
c0 = random.randint(200,204)
config = (p0,c0)
for x in range(w):
for y in range(h):
k = int(round(const*r3))%256
k = bin(k)[2:].ljust(8,'0')
k = int(k[p0%8:]+k[:p0%8],2)
r3 = f3(r3)
p0 = pic[y,x]
c0 = k^((k+p0)%256)^c0
pic[y,x] = c0
return pic,size,config
def decryptImage(path,config):
im = Image.open(path)
size = im.size
pic = np.array(im)
im.close()
r1 = Decimal('0.478706063089473894123')
r2 = Decimal('0.613494245341234672318')
r3 = Decimal('0.946365754637812381837')
w, h = size
for i in range(200):
r1 = f1(r1)
r2 = f2(r2)
r3 = f3(r3)
const = 10 ** 14
p0 = config[0]
c0 = config[1]
for x in range(w):
for y in range(h):
k = int(round(const*r3))%256
k = bin(k)[2:].ljust(8,'0')
k = int(k[p0%8:]+k[:p0%8],2)
r3 = f3(r3)
c1 = pic[y,x]
c0 = (((k^c1^c0)%256)-k)%256
pic[y,x] = c0
p0 = c0
c0 = c1
print(pic)
f = open('test.txt','r')
tihuan = f.read()
tihuan_list = eval(tihuan)
new_pic = pic
for i in tihuan_list[::-1]:
t1 = i[0]
t2 = i[1]
tmp = new_pic[t1[0],t1[1]]
new_pic[t1[0], t1[1]] = new_pic[t2[0],t2[1]]
new_pic[t2[0], t2[1]] = tmp
return new_pic,size,config
def outputImage(path,pic,size):
im = Image.new('P', size,'white')
pixels = im.load()
for i in range(im.size[0]):
for j in range(im.size[1]):
pixels[i,j] = (int(pic[j][i]))
im.save(path)
enc_img = 'flag_enc.bmp'
pic,size,_ = encryptImage(enc_img)
def decmain():
config_list = list()
for p0 in range(100,105):
for c0 in range(200,205):
config = (p0,c0)
config_list.append(config)
for config in config_list:
config_index = config_list.index(config)
enc_img = 'flag_enc.bmp'
dec_img = 'flag_' + str(config_index) + '.bmp'
pic, size, config = decryptImage(enc_img,config)
outputImage(dec_img,pic,size)
decmain()
|
