例题ctfhub/隐写v2.0

打开是一张图片

文件分离得到zip，爆破密码得到7878

打开得到0和1，

!!!不是二进制转图片，直接是二维码

缩小能看到

000000000000000000000000000000000000000000000000000000000000000000000
0000000000000000000000000000000000000000000000000000000000000000000000
0011111111111110110000111110000001001111110000000110000011111111111100
0011111111111110110000111110000001001111110000000110000011111111111100
0011000000000110110000001111100110111111001111111001110011000000000100
0011000000000110110000001111100110111111001111111001110011000000000100
0011001111100110111111110001100111000011110111100111110011011111100100
0011001111100110001111001000011111001111111000011111110011011111100100
0011001111100110001111001000011111001111111000011111110011011111100100
0011001111100110000011000000011001110011000111111000000011011111100100
0011001111100110000011000000011001110011000111111000000011011111100100
0011000000000110110000000110011111000011110001111111110011000000000100
0011000000000110110000000110011111000011110001111111110011000000000100
0011111111111110110011001001100110110011001001100110110011111111111100
0011111111111110110011001001100110110011001001100110110011111111111100
0000000000000000111100000110000110111100000111111000000000000000000000
0000001111100110110000001110000111110011111000000111111111100001111100
0000001111100110110000001110000111110011111000000111111111100001111100
0000110111100001110011110000000000000011000110000001001100111110011000
0000110111100001110011110000000000000011000110000001001100111110011000
0011000000000110000011111110011000110000001000011111111111100111100100
0011000000000110000011111110011000110000001000011111111111100111100100
0000000001111001000011110110011111000000001001100001001100100000000000
0000000001111001000011110110011111000000001001100001001100100000000000
0000001110011110000011110111100000110000000110011001111111111001100100
0000000001111001000011110000011000001111000000011110001100000000011000
0000000001111001000011110000011000001111000000011110001100000000011000
0011111110011110111111001001100111111111001111100001110011011111100100
0011111110011110111111001001100111111111001111100001110011011111100100
0011001000011000001100000001111111111111110001100001111111100000000100
0011001000011000001100000001111111111111110001100001111111100000000100
0011001001100111111100111110011111001100000111111111110011011111100100
0011001001100111111100111110011111001100000111111111110011011111100100
0000110110011001111111000111100001110011001001100000001100100110000000
0011001110000111110011001111100000000011110000000111111111011111111100
0011001110000111110011001111100000000011110000000111111111011111111100
0011000001100000111100000001111000111100110110000000000000100110011000
0011000001100000111100000001111000111100110110000000000000100110011000
0000001000011110111100000111111000110000000000011111110011011001111000
0000001000011110111100000111111000110000000000011111110011011001111000
0000111111111001000000111110011111001111110001100000001100100111111100
0000111111111001000000111110011111001111110001100000001100100111111100
0000111001111110110000111110000001000011000111100001111111100000011100
0011001111111001000011000001111000111111000111100111000011000000011000
0011001111111001000011000001111000111111000111100111000011000000011000
0000110000000110001100110000011110001111111000000001000011000111100000
0000110000000110001100110000011110001111111000000001000011000111100000
0011000001100001110011001110011000001100111001100111110011000110000000
0011000001100001110011001110011000001100111001100111110011000110000000
0011001000000111000011001110011110110011110000000110000000000001111100
0011001000000111000011001110011110110011110000000110000000000001111100
0011001111111001111100111111100111001111001001100110111100000110011100
0011001000011111110011110111111001001111001000011110111111111000000100
0011001000011111110011110111111001001111001000011110111111111000000100
0000000000000000111111110000000111110011110001100001110000011001111000
0000000000000000111111110000000111110011110001100001110000011001111000
0011111111111110000011001000011000001111000001111000110011011110000100
0011111111111110000011001000011000001111000001111000110011011110000100
0011000000000110000011110000000110111111111001100000110000011000000000
0011001111100110111111110001100001111111001001111111111111111111100100
0011001111100110111111110001100001111111001001111111111111111111100100
0011001111100110110011001001111110110011001000000001001111011000011100
0011001111100110110011001001111110110011001000000001001111011000011100
0011001111100110110000000110011001000011001111100001110000100000000100
0011001111100110110000000110011001000011001111100001110000100000000100
0011000000000110001111001111100110110011111110000111110011100000000100
0011000000000110001111001111100110110011111110000111110011100000000100
0011111111111110001111110110000000000011001110000000001100000111111100
0000000000000000000000000000000000000000000000000000000000000000000000
0000000000000000000000000000000000000000000000000000000000000000000000

exp1:0为黑色像素，1为白色像素,70行，70列

from PIL import Image

# 二进制字符串
binary_nums = """0000000000000000000000000000000000000000000000000000000000000000000000
0000000000000000000000000000000000000000000000000000000000000000000000
0011111111111110110000111110000001001111110000000110000011111111111100
0011111111111110110000111110000001001111110000000110000011111111111100
0011000000000110110000001111100110111111001111111001110011000000000100
0011000000000110110000001111100110111111001111111001110011000000000100
0011001111100110111111110001100111000011110111100111110011011111100100
0011001111100110001111001000011111001111111000011111110011011111100100
0011001111100110001111001000011111001111111000011111110011011111100100
0011001111100110000011000000011001110011000111111000000011011111100100
0011001111100110000011000000011001110011000111111000000011011111100100
0011000000000110110000000110011111000011110001111111110011000000000100
0011000000000110110000000110011111000011110001111111110011000000000100
0011111111111110110011001001100110110011001001100110110011111111111100
0011111111111110110011001001100110110011001001100110110011111111111100
0000000000000000111100000110000110111100000111111000000000000000000000
0000001111100110110000001110000111110011111000000111111111100001111100
0000001111100110110000001110000111110011111000000111111111100001111100
0000110111100001110011110000000000000011000110000001001100111110011000
0000110111100001110011110000000000000011000110000001001100111110011000
0011000000000110000011111110011000110000001000011111111111100111100100
0011000000000110000011111110011000110000001000011111111111100111100100
0000000001111001000011110110011111000000001001100001001100100000000000
0000000001111001000011110110011111000000001001100001001100100000000000
0000001110011110000011110111100000110000000110011001111111111001100100
0000000001111001000011110000011000001111000000011110001100000000011000
0000000001111001000011110000011000001111000000011110001100000000011000
0011111110011110111111001001100111111111001111100001110011011111100100
0011111110011110111111001001100111111111001111100001110011011111100100
0011001000011000001100000001111111111111110001100001111111100000000100
0011001000011000001100000001111111111111110001100001111111100000000100
0011001001100111111100111110011111001100000111111111110011011111100100
0011001001100111111100111110011111001100000111111111110011011111100100
0000110110011001111111000111100001110011001001100000001100100110000000
0011001110000111110011001111100000000011110000000111111111011111111100
0011001110000111110011001111100000000011110000000111111111011111111100
0011000001100000111100000001111000111100110110000000000000100110011000
0011000001100000111100000001111000111100110110000000000000100110011000
0000001000011110111100000111111000110000000000011111110011011001111000
0000001000011110111100000111111000110000000000011111110011011001111000
0000111111111001000000111110011111001111110001100000001100100111111100
0000111111111001000000111110011111001111110001100000001100100111111100
0000111001111110110000111110000001000011000111100001111111100000011100
0011001111111001000011000001111000111111000111100111000011000000011000
0011001111111001000011000001111000111111000111100111000011000000011000
0000110000000110001100110000011110001111111000000001000011000111100000
0000110000000110001100110000011110001111111000000001000011000111100000
0011000001100001110011001110011000001100111001100111110011000110000000
0011000001100001110011001110011000001100111001100111110011000110000000
0011001000000111000011001110011110110011110000000110000000000001111100
0011001000000111000011001110011110110011110000000110000000000001111100
0011001111111001111100111111100111001111001001100110111100000110011100
0011001000011111110011110111111001001111001000011110111111111000000100
0011001000011111110011110111111001001111001000011110111111111000000100
0000000000000000111111110000000111110011110001100001110000011001111000
0000000000000000111111110000000111110011110001100001110000011001111000
0011111111111110000011001000011000001111000001111000110011011110000100
0011111111111110000011001000011000001111000001111000110011011110000100
0011000000000110000011110000000110111111111001100000110000011000000000
0011001111100110111111110001100001111111001001111111111111111111100100
0011001111100110111111110001100001111111001001111111111111111111100100
0011001111100110110011001001111110110011001000000001001111011000011100
0011001111100110110011001001111110110011001000000001001111011000011100
0011001111100110110000000110011001000011001111100001110000100000000100
0011001111100110110000000110011001000011001111100001110000100000000100
0011000000000110001111001111100110110011111110000111110011100000000100
0011000000000110001111001111100110110011111110000111110011100000000100
0011111111111110001111110110000000000011001110000000001100000111111100
0000000000000000000000000000000000000000000000000000000000000000000000
0000000000000000000000000000000000000000000000000000000000000000000000""".replace('\n', '')

# 图像尺寸
MAX = 70
pic = Image.new("RGB", (MAX, MAX))

# 填充像素
i = 0
for y in range(MAX):
    for x in range(MAX):
        if binary_nums[i] == '0':
            pic.putpixel((x, y), (0, 0, 0))  # 黑色
        else:


            pic.putpixel((x, y), (255, 255, 255))  # 白色
        i += 1

# 保存图像
pic.save("flag.png")

exp2：简化1

from PIL import Image

# 从 flag.txt 文件中读取二进制字符串
with open('flag.txt', 'r') as file:
    binary_nums = file.read().strip().replace('\n', '')

# 图像尺寸
MAX = 70
pic = Image.new("RGB", (MAX, MAX))

# 填充像素
i = 0
for y in range(MAX):
    for x in range(MAX):
        if binary_nums[i] == '0':
            pic.putpixel((x, y), (0, 0, 0))  # 黑色
        else:
            pic.putpixel((x, y), (255, 255, 255))  # 白色
        i += 1

# 保存图像
pic.save("flag.png")
print("图像已保存为 flag.png")

代码解释

1. PIL (Python Imaging Library)

PIL 是 Python Imaging Library 的缩写，是一个用于处理图像的库。它提供了许多图像处理功能，如读取、修改和保存各种图像格式。PIL 已经不再维护，但它的 fork 版本 Pillow 仍在积极开发和维护中。因此，通常我们会使用 Pillow 而不是原始的 PIL。

2. Image 类

Image 类是 PIL 库中的一个核心类，用于表示和操作图像。你可以通过 Image 类创建新的图像、打开现有的图像文件、修改图像内容以及保存图像。

3. pic 变量

在你的代码中，pic 是一个 Image 对象，表示一个新创建的空白图像。具体来说：

pic = Image.new("RGB", (MAX, MAX))

• "RGB"：指定了图像的颜色模式。RGB 表示图像由红、绿、蓝三种颜色通道组成。
• (MAX, MAX)：指定了图像的尺寸，宽度和高度都是 MAX 像素。

@4. putpixel 方法

putpixel 是 Image 类的一个方法，用于设置图像中某个特定像素的颜色。其语法如下：

image.putpixel((x, y), color)

• (x, y)：表示图像中的一个像素位置，x 和 y 分别是水平和垂直坐标。
• color：表示要设置的颜色。对于 RGB 图像，color 是一个包含三个整数的元组，分别表示红、绿、蓝三个颜色通道的值。例如，(0, 0, 0) 表示黑色，(255, 255, 255) 表示白色。
• 越接近0解释越接近黑色，越接近255解释越接近白色。

代码示例中的 putpixel 使用

在你的代码中，putpixel 方法用于根据 binary_nums 字符串中的值设置图像的像素颜色：

i = 0
for y in range(MAX):
    for x in range(MAX):
        if binary_nums[i] == '0':
            pic.putpixel((x, y), (0, 0, 0))  # 黑色
        else:
            pic.putpixel((x, y), (255, 255, 255))  # 白色
        i += 1

• i 是一个索引，用于遍历 binary_nums 字符串。
• for y in range(MAX) 和 for x in range(MAX) 是嵌套的循环，用于遍历图像的每一个像素位置 (x, y)。
• if binary_nums[i] == '0'：如果当前字符是 0，则将该位置的像素设置为黑色 (0, 0, 0)。
• else：如果当前字符是 1，则将该位置的像素设置为白色 (255, 255, 255)。
• i += 1：每次处理完一个像素后，i 自增 1，以便处理下一个字符。

总结

• PIL：Python Imaging Library，用于处理图像的库。
• Image 类：PIL 中的核心类，用于表示和操作图像。
• pic 变量：一个 Image 对象，表示一个新创建的空白图像。
• putpixel 方法：用于设置图像中某个特定像素的颜色。

通过这些工具，你可以创建和操作图像，生成二维码图像并保存为文件。希望这些解释对你有帮助！