【JAVA】AES加密

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 android.util.Log;

public class AES {

    public static final String TAG = "AESUtils";

    public static String encrypt(String seed, String clearText) {

        Log.d(TAG, "加密前的seed=" + seed + ",内容为:" + clearText);

        byte[] result = null;

        try {

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

            result = encrypt(rawkey, clearText.getBytes());

        } catch (Exception e) {

            e.printStackTrace();

        }

        String content = toHex(result);

         Log.d(TAG, "加密后的内容为:" + content);

        return content;

    }

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

        Log.d(TAG, "解密前的seed=" + seed + ",内容为:" + encrypted);

        byte[] rawKey;

        try {

            rawKey = getRawKey(seed.getBytes());

            byte[] enc = toByte(encrypted);

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

            String coentn = new String(result);

            Log.d(TAG, "解密后的内容为:" + coentn);

            return coentn;

        } catch (Exception e) {

            e.printStackTrace();

            return null;

        }

    }

    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);

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

        cipher.init(Cipher.ENCRYPT_MODE, skeySpec, new IvParameterSpec(

                new byte[cipher.getBlockSize()]));

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

        cipher.init(Cipher.DECRYPT_MODE, skeySpec, new IvParameterSpec(

                new byte[cipher.getBlockSize()]));

        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 static void appendHex(StringBuffer sb, byte b) {

        final String HEX = "0123456789ABCDEF";

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

    }

}