What are the processing methods for Python image watermark encryption?

Encryption Algorithm

The encryption algorithm is an encryption method based on mathematical operations that can encrypt images, making them difficult to read or display directly without decryption. Common encryption algorithms include symmetric encryption algorithms and asymmetric encryption algorithms. Among them, symmetric encryption algorithms use the same key for encryption and decryption. Common symmetric encryption algorithms include AES and DES; asymmetric encryption algorithms use public keys and private keys for encryption and decryption. Common asymmetric encryption algorithms include RSA wait.

For example, you can use the AES encryption algorithm to encrypt pictures. The specific steps are as follows:

# 导入pycryptodome库
from Crypto.Cipher import AES
from Crypto.Util.Padding import pad, unpad
import base64
 
# 定义加密函数
def aes_encrypt(key, data):
    # 将key和iv转换成bytes类型
    key = bytes(key, encoding='utf-8')
    iv = bytes(key, encoding='utf-8')
    # 使用AES算法进行加密
    cipher = AES.new(key, AES.MODE_CBC, iv)
    # 对数据进行补位
    data = pad(data, AES.block_size)
    # 加密
    ciphertext = cipher.encrypt(data)
    # 将加密后的数据进行base64编码
    return base64.b64encode(ciphertext).decode('utf-8')
 
# 定义解密函数
def aes_decrypt(key, data):
    # 将key和iv转换成bytes类型
    key = bytes(key, encoding='utf-8')
    iv = bytes(key, encoding='utf-8')
    # 使用AES算法进行解密
    cipher = AES.new(key, AES.MODE_CBC, iv)
    # 对数据进行解码
    data = base64.b64decode(data)
    # 解密
    plaintext = cipher.decrypt(data)
    # 对解密后的数据进行去补位操作
    return unpad(plaintext, AES.block_size)
 
# 加密图片文件
with open('test.jpg', 'rb') as f:
    data = f.read()
    # 加密图片数据
    encrypted_data = aes_encrypt('1234567890123456', data)
    # 保存加密后的图片数据
    with open('test_encrypted.jpg', 'wb') as f1:
        f1.write(bytes(encrypted_data, encoding='utf-8'))
 
# 解密图片文件
with open('test_encrypted.jpg', 'rb') as f:
    encrypted_data = f.read()
    # 解密图片数据
    decrypted_data = aes_decrypt('1234567890123456', encrypted_data)
    # 保存解密后的图片数据
    with open('test_decrypted.jpg', 'wb') as f1:
        f1.write(decrypted_data)

Watermark

Adding a watermark with a specific mark is a way to prevent the picture from being used maliciously. or misappropriation. Watermarks can be divided into two types: text watermarks and image watermarks. Among them, text watermark is to add a piece of text information to the picture. Common text watermarks include copyright information, author information, etc.; while image watermark is to add a specific image to the picture. Common image watermarks include company logo, 2D Code etc.

For example, you can use the Python Pillow library to watermark images. The specific steps are as follows:

from PIL import Image, ImageDraw, ImageFont
 
# 打开图片文件
img = Image.open('test.jpg')
 
# 创建绘图对象
draw = ImageDraw.Draw(img)
 
# 设置水印文字
text = 'Watermark'
 
# 设置水印字体
font = ImageFont.truetype('arial.ttf', 36)
 
# 设置水印颜色
color = (255, 255, 255, 128)
 
# 设置水印位置
position = (img.size[0]-200, img.size[1]-50)
 
# 添加水印文字
draw.text(position, text, font=font, fill=color)
 
# 保存水印图片文件
img.save('test_watermarked.jpg')

In addition to text watermarks, you can also protect image privacy by adding image watermarks. For example, if you need to add a QR code watermark to a picture, you can use the Python Pillow library. The operation method is as follows:

import qrcode
 
# 打开图片文件
img = Image.open('test.jpg')
 
# 创建二维码对象
qr = qrcode.QRCode(version=1, box_size=10, border=2)
qr.add_data('https://www.example.com')
qr.make(fit=True)
 
# 生成二维码图片
qr_img = qr.make_image(fill_color="black", back_color="white")
 
# 计算二维码位置
pos_x = img.size[0]-qr_img.size[0]-10
pos_y = img.size[1]-qr_img.size[1]-10
position = (pos_x, pos_y)
 
# 添加二维码水印
img.paste(qr_img, position)
 
# 保存水印图片文件
img.save('test_qrcode.jpg')

In this way, you can protect the privacy of the picture by adding a QR code watermark and prevent it from being Unauthorized use.

The encryption algorithm is to encrypt pictures to achieve the purpose of protecting the privacy of pictures. Common encryption algorithms include symmetric encryption and asymmetric encryption. Symmetric encryption is fast but less secure, while asymmetric encryption is slow but more secure.

In order to prevent pictures from being stolen, watermark technology will add specific image information, such as text or pictures, to the pictures. Common watermarking technologies include text watermarks and image watermarks. Text watermarks are simple and easy to implement, while image watermarks require the use of specific QR codes and other technologies.

You need to choose which method to use based on actual needs. For example, for some pictures that do not require high-intensity encryption, text watermarks can be used, and for pictures that require high-intensity protection, an asymmetric encryption algorithm can be used for encryption operations.

Several picture encryption cases in different situations:

Encrypting personal photos

We may sometimes want to encrypt our personal photos , to avoid being viewed at will by others, this can be achieved by using an encryption algorithm. In order to protect the security of the photos, we can encrypt them using the AES encryption algorithm and save the encrypted photos to a safe storage location. Only people with the decryption key can view the photos.

Encrypt commercial confidential images

The business world may need more stringent measures to protect confidential images and prevent theft. We can encrypt it using an asymmetric encryption algorithm. Trade secret images can be encrypted using the RSA algorithm and can only be decrypted and viewed by authorized personnel.

Add digital watermark to pictures

Digital watermark is a relatively simple method of image protection. For example, we can add our signature or company logo to the photo and then save it. Even if a photo is copied or distributed, digital watermarks can still help us identify its origin.

Add QR code watermark to pictures

QR code watermark can add more complex protection measures to pictures. For example, we can use QR code watermarks in commercial advertisements and link the QR code to the company's official website or product introduction page to prevent advertising from being stolen. Only by scanning the correct QR code can you access the real website.

In short, image encryption technology can use different methods according to different situations and needs to achieve better protection.

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