from cryptography.hazmat.primitives.ciphers import Cipher, algorithms, modes
from cryptography.hazmat.primitives import padding
from cryptography.hazmat.backends import default_backend
import os

key = os.urandom(32)  # AES-256密鑰
iv = os.urandom(16)   # IV
cipher = Cipher(algorithms.AES(key), modes.CBC(iv), backend=default_backend())
encryptor = cipher.encryptor()

# 讀取圖片為二進制數(shù)據(jù)
with open("image.jpg", "rb") as f:
    image_data = f.read()

# PKCS7填充
padder = padding.PKCS7(128).padder()
padded_data = padder.update(image_data) + padder.finalize()
encrypted_data = encryptor.update(padded_data) + encryptor.finalize()

# 將加密后的數(shù)據(jù)（含密鑰、IV）傳輸給前端

async function decryptImage(encryptedData, key, iv) {
    const decoder = new TextDecoder();
    const encryptedBytes = new Uint8Array(encryptedData);
    const ivBytes = new Uint8Array(iv);
    const keyBytes = new Uint8Array(key);

    const decoded = await crypto.subtle.decrypt(
        { name: "AES-CBC", iv: ivBytes },
        await crypto.subtle.importKey(
            "raw", keyBytes, "AES-CBC", false, ["decrypt"]
        ),
        encryptedBytes
    );

    // 去除PKCS7填充并生成圖片
    const decryptedData = new Uint8Array(decoded);
    const blob = new Blob([decryptedData], { type: "image/jpeg" });
    const imgUrl = URL.createObjectURL(blob);
    document.getElementById("decryptedImage").src = imgUrl;
}