Java DES文件加密解密 javax.crypto.BadPaddingException: Given final block not properly padded

本工具类经过测试可用，之前写的没有使用CipherInputStream和CipherOutputStream，生成的加密文件与源文件大小不一致，加密时没有问题，解密时总是抛出如下异常：
Exception in thread "main" javax.crypto.BadPaddingException: Given final block not properly padded
    at com.sun.crypto.provider.SunJCE_f.b(DashoA13*..)
    at com.sun.crypto.provider.SunJCE_f.b(DashoA13*..)
    at com.sun.crypto.provider.AESCipher.engineDoFinal(DashoA13*..)
    at javax.crypto.Cipher.doFinal(DashoA13*..)
 
 
其中BASE64底层依赖库没有使用SUN的，而是下载的“javabase64-1.3.1.jar”
 
DESUtils.java
package demo.security;
 
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.OutputStream;
import java.security.Key;
import java.security.SecureRandom;
 
import javax.crypto.Cipher;
import javax.crypto.CipherInputStream;
import javax.crypto.CipherOutputStream;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESKeySpec;
 
/**
 * <p>
 * DES加密解密工具包
 * </p>
 *
 * @author IceWee
 * @date 2012-5-19
 * @version 1.0
 */
public class DESUtils {
   
    private static final String ALGORITHM = "DES";
    private static final int CACHE_SIZE = 1024;
 
    /**
     * <p>
     * 生成随机密钥
     * </p>
     *
     * @return
     * @throws Exception
     */
    public static String getSecretKey() throws Exception {
        return getSecretKey(null);
    }
   
    /**
     * <p>
     * 生成密钥
     * </p>
     *
     * @param seed 密钥种子
     * @return
     * @throws Exception
     */
    public static String getSecretKey(String seed) throws Exception {
        SecureRandom secureRandom;
        if (seed != null && !"".equals(seed))
            secureRandom = new SecureRandom(seed.getBytes());
        else
            secureRandom = new SecureRandom();
        KeyGenerator keyGenerator = KeyGenerator.getInstance(ALGORITHM);
        keyGenerator.init(secureRandom);
        SecretKey secretKey = keyGenerator.generateKey();
        return Base64Utils.encode(secretKey.getEncoded());
    }
   
    /**
     * <p>
     * 加密
     * </p>
     *
     * @param data
     * @param key
     * @return
     * @throws Exception
     */
    public static byte[] encrypt(byte[] data, String key) throws Exception {
        Key k = toKey(Base64Utils.decode(key));
        Cipher cipher = Cipher.getInstance(ALGORITHM);
        cipher.init(Cipher.ENCRYPT_MODE, k);
        return cipher.doFinal(data);
    }
   
    /**
     * <p>
     * 文件加密
     * </p>
     *
     * @param key
     * @param sourceFilePath
     * @param destFilePath
     * @throws Exception
     */
    public static void encryptFile(String key, String sourceFilePath, String destFilePath) throws Exception {
        File sourceFile = new File(sourceFilePath);
        File destFile = new File(destFilePath);
        if (sourceFile.exists() && sourceFile.isFile()) {
            if (!destFile.getParentFile().exists()) {
                destFile.getParentFile().mkdirs();
            }
            destFile.createNewFile();
            InputStream in = new FileInputStream(sourceFile);
            OutputStream out = new FileOutputStream(destFile);
            Key k = toKey(Base64Utils.decode(key));
            Cipher cipher = Cipher.getInstance(ALGORITHM);
            cipher.init(Cipher.ENCRYPT_MODE, k);
            CipherInputStream cin = new CipherInputStream(in, cipher);
            byte[] cache = new byte[CACHE_SIZE];
            int nRead = 0;
            while ((nRead = cin.read(cache)) != -1) {
                out.write(cache, 0, nRead);
                out.flush();
            }
            out.close();
            cin.close();
            in.close();
        }
    }
   
    /**
     * <p>
     * 解密
     * </p>
     *
     * @param data
     * @param key
     * @return
     * @throws Exception
     */
    public static byte[] decrypt(byte[] data,

补充：综合编程 , 安全编程 ,