用AESencryption/解密

有没有一个很好的例子，如何在Android上使用AES encryption/解密 Image和其他文件？ 我正在做一个项目，需要encryption/解密数据，但我不知道如何去做。

Answer 1

警告：此答案包含您不应该使用的代码，因为它是不安全的（使用SHA1PRNG进行密钥派生，并在ECB模式下使用AES）

相反，使用PBKDF2WithHmacSHA1进行密钥派生，在CBC或GCM模式下使用AES（GCM提供隐私和完整性）

你可以使用这样的函数：

 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; } 

并像这样调用它们：

 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); 

这应该工作，我现在在一个项目中使用类似的代码。

Answer 2

 import java.security.AlgorithmParameters; import java.security.SecureRandom; import java.security.spec.KeySpec; import javax.crypto.Cipher; import javax.crypto.KeyGenerator; import javax.crypto.SecretKey; import javax.crypto.SecretKeyFactory; import javax.crypto.spec.IvParameterSpec; import javax.crypto.spec.PBEKeySpec; import javax.crypto.spec.SecretKeySpec; class SecurityUtils { private static final byte[] salt = { (byte) 0xA4, (byte) 0x0B, (byte) 0xC8, (byte) 0x34, (byte) 0xD6, (byte) 0x95, (byte) 0xF3, (byte) 0x13 }; private static int BLOCKS = 128; public static byte[] encryptAES(String seed, String cleartext) throws Exception { byte[] rawKey = getRawKey(seed.getBytes("UTF8")); SecretKeySpec skeySpec = new SecretKeySpec(rawKey, "AES"); Cipher cipher = Cipher.getInstance("AES"); cipher.init(Cipher.ENCRYPT_MODE, skeySpec); return cipher.doFinal(cleartext.getBytes("UTF8")); } public static byte[] decryptAES(String seed, byte[] data) throws Exception { byte[] rawKey = getRawKey(seed.getBytes("UTF8")); SecretKeySpec skeySpec = new SecretKeySpec(rawKey, "AES"); Cipher cipher = Cipher.getInstance("AES"); cipher.init(Cipher.DECRYPT_MODE, skeySpec); return cipher.doFinal(data); } private static byte[] getRawKey(byte[] seed) throws Exception { KeyGenerator kgen = KeyGenerator.getInstance("AES"); SecureRandom sr = SecureRandom.getInstance("SHA1PRNG"); sr.setSeed(seed); kgen.init(BLOCKS, sr); // 192 and 256 bits may not be available SecretKey skey = kgen.generateKey(); byte[] raw = skey.getEncoded(); return raw; } private static byte[] pad(byte[] seed) { byte[] nseed = new byte[BLOCKS / 8]; for (int i = 0; i < BLOCKS / 8; i++) nseed[i] = 0; for (int i = 0; i < seed.length; i++) nseed[i] = seed[i]; return nseed; } public static byte[] encryptPBE(String password, String cleartext) throws Exception { SecretKeyFactory factory = SecretKeyFactory .getInstance("PBKDF2WithHmacSHA1"); KeySpec spec = new PBEKeySpec(password.toCharArray(), salt, 1024, 256); SecretKey tmp = factory.generateSecret(spec); SecretKey secret = new SecretKeySpec(tmp.getEncoded(), "AES"); Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding"); cipher.init(Cipher.ENCRYPT_MODE, secret); AlgorithmParameters params = cipher.getParameters(); byte[] iv = params.getParameterSpec(IvParameterSpec.class).getIV(); return cipher.doFinal(cleartext.getBytes("UTF-8")); } public static String decryptPBE(SecretKey secret, String ciphertext, byte[] iv) throws Exception { Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding"); cipher.init(Cipher.DECRYPT_MODE, secret, new IvParameterSpec(iv)); return new String(cipher.doFinal(ciphertext.getBytes()), "UTF-8"); } } 

Answer 3

老问题，但我升级支持Android的前后4.2的答案，并根据Android开发人员的博客考虑所有最近的变化

另外，我在我的github回购中留下了一个工作示例。

 import java.nio.charset.Charset; import java.security.AlgorithmParameters; import java.security.SecureRandom; import javax.crypto.Cipher; import javax.crypto.KeyGenerator; import javax.crypto.SecretKey; import javax.crypto.spec.IvParameterSpec; import javax.crypto.spec.SecretKeySpec; import org.apache.commons.codec.binary.Base64; /* * This software is provided 'as-is', without any express or implied * warranty. In no event will Google be held liable for any damages * arising from the use of this software. * * Permission is granted to anyone to use this software for any purpose, * including commercial applications, and to alter it and redistribute it * freely, as long as the origin is not misrepresented. * * @author: Ricardo Champa * */ public class MyCipher { private final static String ALGORITHM = "AES"; private String mySecret; public MyCipher(String mySecret){ this.mySecret = mySecret; } public MyCipherData encryptUTF8(String data){ try{ byte[] bytes = data.toString().getBytes("utf-8"); byte[] bytesBase64 = Base64.encodeBase64(bytes); return encrypt(bytesBase64); } catch(Exception e){ MyLogs.show(e.getMessage()); return null; } } public String decryptUTF8(byte[] encryptedData, IvParameterSpec iv){ try { byte[] decryptedData = decrypt(encryptedData, iv); byte[] decodedBytes = Base64.decodeBase64(decryptedData); String restored_data = new String(decodedBytes, Charset.forName("UTF8")); return restored_data; } catch (Exception e) { MyLogs.show(e.getMessage());; return null; } } //AES private MyCipherData encrypt(byte[] raw, byte[] clear) throws Exception { SecretKeySpec skeySpec = new SecretKeySpec(raw, ALGORITHM); Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding"); //solved using PRNGFixes class cipher.init(Cipher.ENCRYPT_MODE, skeySpec); byte[] data = cipher.doFinal(clear); AlgorithmParameters params = cipher.getParameters(); byte[] iv = params.getParameterSpec(IvParameterSpec.class).getIV(); return new MyCipherData(data, iv); } private byte[] decrypt(byte[] raw, byte[] encrypted, IvParameterSpec iv) throws Exception { SecretKeySpec skeySpec = new SecretKeySpec(raw, ALGORITHM); Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding"); cipher.init(Cipher.DECRYPT_MODE, skeySpec, iv); byte[] decrypted = cipher.doFinal(encrypted); return decrypted; } private byte[] getKey() throws Exception{ byte[] keyStart = this.mySecret.getBytes("utf-8"); KeyGenerator kgen = KeyGenerator.getInstance(ALGORITHM); SecureRandom sr = SecureRandom.getInstance("SHA1PRNG", "Crypto"); // if (android.os.Build.VERSION.SDK_INT >= 17) { // sr = SecureRandom.getInstance("SHA1PRNG", "Crypto"); // } else { // 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(); return key; } //////////////////////////////////////////////////////////// private MyCipherData encrypt(byte[] data) throws Exception{ return encrypt(getKey(),data); } private byte[] decrypt(byte[] encryptedData, IvParameterSpec iv) throws Exception{ return decrypt(getKey(),encryptedData, iv); } } 

Answer 4

如果你正在encryption一个文本文件，那么下面的testing/示例可能是有用的。 它执行以下操作：

1. 创build一个字节stream，
2. 用AESencryption包装，
3. 用文本处理来包装它

4. 并最后缓冲它

    // AESdemo public class AESdemo extends Activity { boolean encryptionIsOn = true; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_aesdemo); // needs <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" /> String homeDirName = Environment.getExternalStorageDirectory().getAbsolutePath() + "/" + getPackageName(); File file = new File(homeDirName, "test.txt"); byte[] keyBytes = getKey("password"); try { File dir = new File(homeDirName); if (!dir.exists()) dir.mkdirs(); if (!file.exists()) file.createNewFile(); OutputStreamWriter osw; if (encryptionIsOn) { Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding"); SecretKeySpec secretKeySpec = new SecretKeySpec(keyBytes, "AES"); IvParameterSpec ivParameterSpec = new IvParameterSpec(keyBytes); cipher.init(Cipher.ENCRYPT_MODE, secretKeySpec, ivParameterSpec); FileOutputStream fos = new FileOutputStream(file); CipherOutputStream cos = new CipherOutputStream(fos, cipher); osw = new OutputStreamWriter(cos, "UTF-8"); } else // not encryptionIsOn osw = new FileWriter(file); BufferedWriter out = new BufferedWriter(osw); out.write("This is a test\n"); out.close(); } catch (Exception e) { System.out.println("Encryption Exception "+e); } /////////////////////////////////// try { InputStreamReader isr; if (encryptionIsOn) { Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding"); SecretKeySpec secretKeySpec = new SecretKeySpec(keyBytes, "AES"); IvParameterSpec ivParameterSpec = new IvParameterSpec(keyBytes); cipher.init(Cipher.DECRYPT_MODE, secretKeySpec, ivParameterSpec); FileInputStream fis = new FileInputStream(file); CipherInputStream cis = new CipherInputStream(fis, cipher); isr = new InputStreamReader(cis, "UTF-8"); } else isr = new FileReader(file); BufferedReader in = new BufferedReader(isr); String line = in.readLine(); System.out.println("Text read: <"+line+">"); in.close(); } catch (Exception e) { System.out.println("Decryption Exception "+e); } } private byte[] getKey(String password) throws UnsupportedEncodingException { String key = ""; while (key.length() < 16) key += password; return key.substring(0, 16).getBytes("UTF-8"); } } 

Answer 5

简单的API在Android上执行AESencryption。 这是与AESCrypt库Ruby和Obj-C（具有相同的默认值）的Android对应：

https://github.com/scottyab/AESCrypt-Android

Answer 6

为Android项目添加充气城堡： https ： //mvnrepository.com/artifact/org.bouncycastle/bcprov-jdk16/1.45

在主要活动中添加以下行：

 static { Security.addProvider(new BouncyCastleProvider()); } 

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 public class AESHelper { private static final String TAG = "AESHelper"; public static byte[] encrypt(byte[] data, String initVector, String key) { try { IvParameterSpec iv = new IvParameterSpec(initVector.getBytes("UTF-8")); Cipher c = Cipher.getInstance("AES/CBC/PKCS5PADDING"); SecretKeySpec k = new SecretKeySpec(Base64.decode(key, Base64.DEFAULT), "AES"); c.init(Cipher.ENCRYPT_MODE, k, iv); return c.doFinal(data); } catch (Exception e) { e.printStackTrace(); } return null; } public static byte[] decrypt(byte[] data, String initVector, String key) { try { IvParameterSpec iv = new IvParameterSpec(initVector.getBytes("UTF-8")); Cipher c = Cipher.getInstance("AES/CBC/PKCS5PADDING"); SecretKeySpec k = new SecretKeySpec(Base64.decode(key, Base64.DEFAULT), "AES"); c.init(Cipher.DECRYPT_MODE, k, iv); return c.doFinal(data); } catch (Exception e) { e.printStackTrace(); } return null; } public static String keyGenerator() throws NoSuchAlgorithmException { KeyGenerator keyGenerator = KeyGenerator.getInstance("AES"); keyGenerator.init(192); return Base64.encodeToString(keyGenerator.generateKey().getEncoded(), Base64.DEFAULT); } }