java实现的AES加密算法完整实例

import javax.crypto.Cipher;import javax.crypto.spec.IvParameterSpec;import javax.crypto.spec.SecretKeySpec;import android.util.Base64;/** * @author vipin.cb , vipin.cb@experionglobal.com <br> *     Sep 27, 2013, 5:18:34 PM <br> *     Package:- <b>com.veebow.util</b> <br> *     Project:- <b>Veebow</b> *     <p> */public class AESCrypt {  private final Cipher cipher;  private final SecretKeySpec key;  private AlgorithmParameterSpec spec;  public static final String SEED_16_CHARACTER = "U1MjU1M0FDOUZ.Qz";  public AESCrypt() throws Exception {    // hash password with SHA-256 and crop the output to 128-bit for key    MessageDigest digest = MessageDigest.getInstance("SHA-256");    digest.update(SEED_16_CHARACTER.getBytes("UTF-8"));    byte[] keyBytes = new byte[32];    System.arraycopy(digest.digest(), 0, keyBytes, 0, keyBytes.length);    cipher = Cipher.getInstance("AES/CBC/PKCS7Padding");    key = new SecretKeySpec(keyBytes, "AES");    spec = getIV();  }  public AlgorithmParameterSpec getIV() {    byte[] iv = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, };    IvParameterSpec ivParameterSpec;    ivParameterSpec = new IvParameterSpec(iv);    return ivParameterSpec;  }  public String encrypt(String plainText) throws Exception {    cipher.init(Cipher.ENCRYPT_MODE, key, spec);    byte[] encrypted = cipher.doFinal(plainText.getBytes("UTF-8"));    String encryptedText = new String(Base64.encode(encrypted,        Base64.DEFAULT), "UTF-8");    return encryptedText;  }  public String decrypt(String cryptedText) throws Exception {    cipher.init(Cipher.DECRYPT_MODE, key, spec);    byte[] bytes = Base64.decode(cryptedText, Base64.DEFAULT);    byte[] decrypted = cipher.doFinal(bytes);    String decryptedText = new String(decrypted, "UTF-8");    return decryptedText;  }}