2010计算机软考程序员辅导资料《javaAES算法》

 　　package com.rsa;

　　import java.security.InvalidAlgorithmParameterException;

　　import java.security.InvalidKeyException;

　　import java.security.NoSuchAlgorithmException;

　　import java.security.SecureRandom;

　　import java.security.spec.AlgorithmParameterSpec;

　　import javax.crypto.BadPaddingException;

　　import javax.crypto.Cipher;

　　import javax.crypto.IllegalBlockSizeException;

　　import javax.crypto.KeyGenerator;

　　import javax.crypto.NoSuchPaddingException;

　　import javax.crypto.SecretKey;

　　import javax.crypto.spec.IvParameterSpec;

　　public class AESEncrypter {public static byte[] iv = new byte[] { 82, 22, 50, 44, -16, 124, -40, -114, -87, -40, 37, 23, -56, 23, -33, 75 };

　　private static AESEncrypter aes = null;

　　public static byte[] key1 = new byte[] { -42, 35, 67, -86, 19, 29, -11, 84, 94, 111, 75, -104, 71, 46, 86, -21, -119, 110, -11, -32, -28, 91, -33, -46, 99, 49, 2, 66, -101, -11, -8, 56 };

　　private AESEncrypter() {}

　　public static synchronized AESEncrypter getInstance() {if (aes == null) {aes = new AESEncrypter();}

　　return aes;}

　　public String encrypt(String msg) {String str = "";try {KeyGenerator kgen = KeyGenerator.getInstance("AES");kgen.init(128, new SecureRandom(key1));

　　AlgorithmParameterSpec paramSpec = new IvParameterSpec(iv);

　　SecretKey key = kgen.generateKey();

　　Cipher ecipher = Cipher.getInstance("AES/CBC/PKCS5Padding");

　　ecipher.init(Cipher.ENCRYPT_MODE, key, paramSpec);

　　str = asHex(ecipher.doFinal(msg.getBytes()));

　　} catch (BadPaddingException e) {e.printStackTrace();

　　} catch (NoSuchAlgorithmException e) {e.printStackTrace();

　　} catch (NoSuchPaddingException e) {e.printStackTrace();　} catch (InvalidKeyException e) {

　　e.printStackTrace();} catch (InvalidAlgorithmParameterException e) {e.printStackTrace();} catch (IllegalBlockSizeException e) {e.printStackTrace();}

　　return str;}

　　public String decrypt(String value) {try {

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

　　kgen.init(128, new SecureRandom(key1));

　　AlgorithmParameterSpec paramSpec = new IvParameterSpec(iv);

　　SecretKey key = kgen.generateKey();

　　Cipher dcipher = Cipher.getInstance("AES/CBC/PKCS5Padding");

　　dcipher.init(Cipher.DECRYPT_MODE, key, paramSpec);

　　return new String(dcipher.doFinal(asBin(value)));} catch (BadPaddingException e) {

　　e.printStackTrace();} catch (NoSuchAlgorithmException e) {e.printStackTrace();} catch (NoSuchPaddingException e) {e.printStackTrace();} catch (InvalidKeyException e) {

　　e.printStackTrace();} catch (InvalidAlgorithmParameterException e) {

　　e.printStackTrace();} catch (IllegalBlockSizeException e) {

　　e.printStackTrace();}

　　return "";}

　　private String asHex(byte buf[]) {

　　StringBuffer strbuf = new StringBuffer(buf.length * 2);

　　int i;

　　for (i = 0; i < buf.length; i++) {if (((int) buf[i] & 0xff) < 0x10)strbuf.append("0");strbuf.append(Long.toString((int) buf[i] & 0xff, 16));}

　　return strbuf.toString();}

　　private byte[] asBin(String src) {

　　if (src.length() < 1)

　　return null;

　　byte[] encrypted = new byte[src.length() / 2];

　　for (int i = 0; i < src.length() / 2; i++) {

　　int high = Integer.parseInt(src.substring(i * 2, i * 2 + 1), 16);

　　int low = Integer.parseInt(src.substring(i * 2 + 1, i * 2 + 2), 16);

　　encrypted[i] = (byte) (high * 16 + low);}

　　return encrypted;}

　　public static void main(String args[]) {

　　String str = AESEncrypter.getInstance().encrypt("192.168.30.193.123");

　　System.out.println(str);

　　System.out.println(AESEncrypter.getInstance().decrypt(str));}}