java AES加密解密实例

新建SimpleCrypto类代码如下：

package test2;

import java.security.SecureRandom;

import javax.crypto.Cipher;

import javax.crypto.KeyGenerator;

import javax.crypto.SecretKey;

import javax.crypto.spec.SecretKeySpec;

public class SimpleCrypto { 

public static String encrypt(String seed, String cleartext) throws Exception { 

byte[] rawKey = getRawKey(seed.getBytes()); 

byte[] result = encrypt(rawKey, cleartext.getBytes()); 

return toHex(result); 

} 

public static String decrypt(String seed, String encrypted) throws Exception { 

byte[] rawKey = getRawKey(seed.getBytes()); 

byte[] enc = toByte(encrypted); 

byte[] result = decrypt(rawKey, enc); 

return new String(result); 

} 

private static byte[] getRawKey(byte[] seed) throws Exception { 

KeyGenerator kgen = KeyGenerator.getInstance("AES"); 

SecureRandom sr = SecureRandom.getInstance("SHA1PRNG"); 

sr.setSeed(seed); 

kgen.init(128, sr); // 192 and 256 bits may not be available 

SecretKey skey = kgen.generateKey(); 

byte[] raw = skey.getEncoded(); 

return raw; 

} 

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; 

} 

public static String toHex(String txt) { 

return toHex(txt.getBytes()); 

} 

public static String fromHex(String hex) { 

return new String(toByte(hex)); 

} 

public static byte[] toByte(String hexString) { 

int len = hexString.length()/2; 

byte[] result = new byte[len]; 

for (int i = 0; i < len; i++) 

result[i] = Integer.valueOf(hexString.substring(2*i, 2*i+2), 16).byteValue(); 

return result; 

} 

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 final static String HEX = "0123456789ABCDEF"; 

private static void appendHex(StringBuffer sb, byte b) { 

sb.append(HEX.charAt((b>>4)&0x0f)).append(HEX.charAt(b&0x0f)); 

} 

} 主类代码：

package test2;

public class Mydemo {

public static void main(String[] args) {

// TODO 自动生成的方法存根

SimpleCrypto sc=new SimpleCrypto();

String  str="";

try {

str = sc.encrypt("123", "云未归来");

} catch (Exception e) {

// TODO 自动生成的 catch 块

e.printStackTrace();

}

System.out.println(str);

try {

str = sc.decrypt("123",str);

} catch (Exception e) {

// TODO 自动生成的 catch 块

e.printStackTrace();

}

System.out.print(str);

}

} 运行结果：

4B6711A6C8AF43CD4391275A1669720E

云未归来