自动生成AES密钥 并使用生成的进行加密解密1

/**

* 自动生成AES128位密钥

*/

public static void getA221(){

try {

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

kg.init(128);//要生成多少位，只需要修改这里即可128, 192或256

SecretKey sk = kg.generateKey();

byte[] b = sk.getEncoded();

String s = byteToHexString(b);

System.out.println(s);

System.out.println("十六进制密钥长度为"+s.length());

System.out.println("二进制密钥的长度为"+s.length()*4);

} catch (NoSuchAlgorithmException e) {

e.printStackTrace();

System.out.println("没有此算法。");

}

}

/**

* 二进制byte[]转十六进制string

*/

public static String byteToHexString(byte[] bytes){

StringBuffer sb = new StringBuffer();

for (int i = 0; i < bytes.length; i++) {

String strHex=Integer.toHexString(bytes[i]);

if(strHex.length() > 3){

sb.append(strHex.substring(6));

} else {

if(strHex.length() < 2){

sb.append("0" + strHex);

} else {

sb.append(strHex);

}

}

}

return sb.toString();

}

/**

* 十六进制string转二进制byte[]

*/

public static byte[] hexStringToByte(String s) {

byte[] baKeyword = new byte[s.length() / 2];

for (int i = 0; i < baKeyword.length; i++) {

try {

baKeyword[i] = (byte) (0xff & Integer.parseInt(s.substring(i * 2, i * 2 + 2), 16));

} catch (Exception e) {

System.out.println("十六进制转byte发生错误！！！");

e.printStackTrace();

}

}

return baKeyword;

}

/**

* 使用对称密钥进行加密

*/

public static void getA231() throws Exception{

String keys = "c0e9fcff59ecc3b8b92939a1a2724a44";//密钥

byte[] keyb = hexStringToByte(keys);

String mingwen = "hello word!";//明文

SecretKeySpec sKeySpec = new SecretKeySpec(keyb, "AES");

Cipher cipher = Cipher.getInstance("AES");

cipher.init(Cipher.ENCRYPT_MODE, sKeySpec);

byte[] bjiamihou = cipher.doFinal(mingwen.getBytes());

System.out.println(byteToHexString(bjiamihou));//加密后数据为ecf0a6bc80dbaf657eac9b06ecd92962

}

/**

* 使用对称密钥进行解密

*/

public static void getA232() throws Exception{

String keys = "c0e9fcff59ecc3b8b92939a1a2724a44";//密钥

byte[] keyb = hexStringToByte(keys);

String sjiami = "ecf0a6bc80dbaf657eac9b06ecd92962";//密文

byte[] miwen = hexStringToByte(sjiami);

SecretKeySpec sKeySpec = new SecretKeySpec(keyb, "AES");

Cipher cipher = Cipher.getInstance("AES");

cipher.init(Cipher.DECRYPT_MODE, sKeySpec);

byte[] bjiemihou = cipher.doFinal(miwen);

System.out.println(new String(bjiemihou));

}