什么是aes加密?
高级加密标准(英语:Advanced Encryption Standard,缩写:AES),在密码学中又称Rijndael加密法,是美国联邦政府采用的一种区块加密标准。这个标准用来替代原先的DES,已经被多方分析且广为全世界所使用。
对于AesUtils类常量简介:
private final static String HEX = "0ABCDEF"; private static final String CBC_PKCS5_PADDING = "AES/CBC/PKCS5Padding";//AES是加密方式 CBC是工作模式 PKCS5Padding是填充模式 private static final String AES = "AES";//AES 加密 private static final String SHA1PRNG="SHA1PRNG"; SHA1PRNG 强随机种子算法, 要区别4.2以上版本的调用方法
如何生成一个随机Key?
/* * 生成随机数,可以当做动态的密钥 加密和解密的密钥必须一致,不然将不能解密 */ public static String generateKey() { try { SecureRandom localSecureRandom = SecureRandom.getInstance(SHA1PRNG); byte[] bytes_key = new byte[20]; localSecureRandom.nextBytes(bytes_key); String str_key = toHex(bytes_key); return str_key; } catch (Exception e) { e.printStackTrace(); } return null; }
Aes密钥处理
// 对密钥进行处理 private static byte[] getRawKey(byte[] seed) throws Exception { KeyGenerator kgen = KeyGenerator.getInstance(AES); //for android SecureRandom sr = null; // 在4.2以上版本中,SecureRandom获取方式发生了改变 if (android.os.Build.VERSION.SDK_INT >= 17) { sr = SecureRandom.getInstance(SHA1PRNG, "Crypto"); } else { sr = SecureRandom.getInstance(SHA1PRNG); } // for Java // secureRandom = SecureRandom.getInstance(SHA1PRNG); sr.setSeed(seed); kgen.init(128, sr); //256 bits or 128 bits,192bits //AES中128位密钥版本有10个加密循环,192比特密钥版本有12个加密循环,256比特密钥版本则有14个加密循环。 SecretKey skey = kgen.generateKey(); byte[] raw = skey.getEncoded(); return raw; }
Aes加密过程
/* * 加密 */ public static String encrypt(String key, String cleartext) { if (TextUtils.isEmpty(cleartext)) { return cleartext; } try { byte[] result = encrypt(key, cleartext.getBytes()); return Base64Encoder.encode(result); } catch (Exception e) { e.printStackTrace(); } return null; } /* * 加密 */ private static byte[] encrypt(String key, byte[] clear) throws Exception { byte[] raw = getRawKey(key.getBytes()); SecretKeySpec skeySpec = new SecretKeySpec(raw, AES); Cipher cipher = Cipher.getInstance(CBC_PKCS5_PADDING); cipher.init(Cipher.ENCRYPT_MODE, skeySpec, new IvParameterSpec(new byte[cipher.getBlockSize()])); byte[] encrypted = cipher.doFinal(clear); return encrypted; }
Aes解密过程
/* * 解密 */ public static String decrypt(String key, String encrypted) { if (TextUtils.isEmpty(encrypted)) { return encrypted; } try { byte[] enc = Base64Decoder.decodeToBytes(encrypted); byte[] result = decrypt(key, enc); return new String(result); } catch (Exception e) { e.printStackTrace(); } return null; } /* * 解密 */ private static byte[] decrypt(String key, byte[] encrypted) throws Exception { byte[] raw = getRawKey(key.getBytes()); SecretKeySpec skeySpec = new SecretKeySpec(raw, AES); Cipher cipher = Cipher.getInstance(CBC_PKCS5_PADDING); cipher.init(Cipher.DECRYPT_MODE, skeySpec, new IvParameterSpec(new byte[cipher.getBlockSize()])); byte[] decrypted = cipher.doFinal(encrypted); return decrypted; }
二进制转字符
//二进制转字符 public static String toHex(byte[] buf) { if (buf == null) return ""; StringBuffer result = new StringBuffer(2 * buf.length); for (int i = 0; i < buf.length; i++) { appendHex(result, buf[i]); } return result.toString(); } private static void appendHex(StringBuffer sb, byte b) { sb.append(HEX.charAt((b >> 4) & 0x0f)).append(HEX.charAt(b & 0x0f)); }
测试程序:
List<Person> personList = new ArrayList<>(); int testMaxCount = 1000;//测试的最大数据条数 //添加测试数据 for (int i = 0; i < testMaxCount; i++) { Person person = new Person(); person.setAge(i); person.setName(String.valueOf(i)); personList.add(person); } //FastJson生成json数据 String jsonData = JsonUtils.objectToJsonForFastJson(personList); Log.e("MainActivity", "AES加密前json数据 ---->" + jsonData); Log.e("MainActivity", "AES加密前json数据长度 ---->" + jsonData.length()); //生成一个动态key String secretKey = AesUtils.generateKey(); Log.e("MainActivity", "AES动态secretKey ---->" + secretKey); //AES加密 long start = System.currentTimeMillis(); String encryStr = AesUtils.encrypt(secretKey, jsonData); long end = System.currentTimeMillis(); Log.e("MainActivity", "AES加密耗时 cost time---->" + (end - start)); Log.e("MainActivity", "AES加密后json数据 ---->" + encryStr); Log.e("MainActivity", "AES加密后json数据长度 ---->" + encryStr.length()); //AES解密 start = System.currentTimeMillis(); String decryStr = AesUtils.decrypt(secretKey, encryStr); end = System.currentTimeMillis(); Log.e("MainActivity", "AES解密耗时 cost time---->" + (end - start)); Log.e("MainActivity", "AES解密后json数据 ---->" + decryStr);
运行耗时:
数据前后变化:
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