用AES加密/解密 [英] android encryption/decryption with AES

问题描述

有没有一个很好的例子，说明如何使用 AES 图像和其他文件$ c>在Android上？我正在开发一个需要加密/解密数据的项目，但我不太确定如何做。

解决方案

警告：此答案包含您不应使用的代码，因为它不安全（使用SHA1PRNG进行密钥导出并在ECB模式下使用AES）

相反，使用PBKDF2WithHmacSHA1进行密钥推导和AES在CBC或GCM模式（GCM提供隐私和完整性）

您可以使用这些功能：

  private static byte [] encrypt（byte [] raw，byte [] clear）throws异常{
 SecretKeySpec skeySpec = new SecretKeySpec（raw， AES）; 
密码密码= Cipher.getInstance（AES）; 
 cipher.init（Cipher.ENCRYPT_MODE，skeySpec）; 
 byte [] encrypted = cipher.doFinal（clear）; 
返回加密; 
} 
 
私有静态字节[] decrypt（byte [] raw，byte [] encrypted）throws异常{
 SecretKeySpec skeySpec = new SecretKeySpec（raw，AES）; 
密码密码= Cipher.getInstance（AES）; 
 cipher.init（Cipher.DECRYPT_MODE，skeySpec）; 
 byte [] decryptpted = cipher.doFinal（encrypted）; 
返回解密; 
} 
  

并像下面这样调用：

  ByteArrayOutputStream baos = new ByteArrayOutputStream（）; 
 bm.compress（Bitmap.CompressFormat.PNG，100，baos）; // bm是位图对象
 byte [] b = baos.toByteArray（）; 
 
 byte [] keyStart =这是一个键.getBytes（）; 
 KeyGenerator kgen = KeyGenerator.getInstance（AES）; 
 SecureRandom sr = SecureRandom.getInstance（SHA1PRNG）; 
 sr.setSeed（keyStart）; 
 kgen.init（128，sr）; // 192和256位可能不可用
 SecretKey skey = kgen.generateKey（）; 
 byte [] key = skey.getEncoded（）; 
 
 // encrypt 
 byte [] encryptedData = encrypt（key，b）; 
 // decrypt 
 byte [] decryptptedData = decrypt（key，encryptedData）; 
  

这应该工作，我现在在项目中使用类似的代码。

Is there a good example of how to encrypt/decrypt Image and other files with AES on Android? I'm working on a project which needs to encrypt/decrypt data but I'm not really sure how to do it.

解决方案

Warning: This answer contains code you should not use as it is insecure (using SHA1PRNG for key derivation and using AES in ECB mode)

Instead, use PBKDF2WithHmacSHA1 for key derivation and AES in CBC or GCM mode (GCM provides both privacy and integrity)

You could use functions like these:

private static byte[] encrypt(byte[] raw, byte[] clear) throws Exception {
    SecretKeySpec skeySpec = new SecretKeySpec(raw, "AES");
    Cipher cipher = Cipher.getInstance("AES");
    cipher.init(Cipher.ENCRYPT_MODE, skeySpec);
    byte[] encrypted = cipher.doFinal(clear);
    return encrypted;
}

private static byte[] decrypt(byte[] raw, byte[] encrypted) throws Exception {
    SecretKeySpec skeySpec = new SecretKeySpec(raw, "AES");
    Cipher cipher = Cipher.getInstance("AES");
    cipher.init(Cipher.DECRYPT_MODE, skeySpec);
    byte[] decrypted = cipher.doFinal(encrypted);
    return decrypted;
}

And invoke them like this:

ByteArrayOutputStream baos = new ByteArrayOutputStream();  
bm.compress(Bitmap.CompressFormat.PNG, 100, baos); // bm is the bitmap object   
byte[] b = baos.toByteArray();  

byte[] keyStart = "this is a key".getBytes();
KeyGenerator kgen = KeyGenerator.getInstance("AES");
SecureRandom sr = SecureRandom.getInstance("SHA1PRNG");
sr.setSeed(keyStart);
kgen.init(128, sr); // 192 and 256 bits may not be available
SecretKey skey = kgen.generateKey();
byte[] key = skey.getEncoded();    

// encrypt
byte[] encryptedData = encrypt(key,b);
// decrypt
byte[] decryptedData = decrypt(key,encryptedData);

This should work, I use similar code in a project right now.

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