对称加解密算法解析

/**
 * 加密工具类
 * 
 * <pre>
 * AES支持128/192/256,取决于密钥长度(与位数对应)
 * DES密钥长度8字节
 * 3DES密钥长度24字节
 * 
 * 采用CBC 需指定初始向量IV，长度与分组大小相同
 * DES为8字节；AES为16字节
 * 
 * </pre>
 */
public class Crypto {
    static {
        // add bouncycastle support for md4 etc..
        Security.addProvider(new BouncyCastleProvider());
    }
    public static enum CryptType {
        DES_ECB_PKCS5("DES/ECB/PKCS5Padding"),
        DES_CBC_PKCS5("DES/CBC/PKCS5Padding", 8),
        DESede_ECB_PKCS5("DESede/ECB/PKCS5Padding"),
        DESede_CBC_PKCS5("DESede/CBC/PKCS5Padding", 8),
        AES_ECB_PKCS5("AES/CBC/PKCS5Padding", 16),
        AES_CBC_PKCS5("AES/CBC/PKCS5Padding", 16),
        AES_CBC_PKCS7("AES/CBC/PKCS7Padding", 16);
        public final String algorithm;
        public final String keyAlg;
        public final int ivlen;
        private CryptType(String algorithm, int ivlen) {
            this.algorithm = algorithm;
            this.keyAlg = this.algorithm.substring(0, this.algorithm.indexOf('/'));
            this.ivlen = ivlen;
        }
        private CryptType(String algorithm) {
            this(algorithm, 0);
        }
        @Override
        public String toString() {
            return this.algorithm;
        }
    }
    /**
     * Initialize the key
     * 
     * @param type
     * @return
     */
    public static String initKey(CryptType type) {
        try {
            KeyGenerator generator = KeyGenerator.getInstance(type.keyAlg);
            SecretKey secretKey = generator.generateKey();
            byte[] key = secretKey.getEncoded();
            return Codec.byteToHexString(key);
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }
    /**
     * generate default ivparam for type
     * 
     * @return
     */
    public static byte[] generateDefaultIv(CryptType type) {
        byte[] iv = new byte[type.ivlen];
        for (int i = 0; i < iv.length; i++) {
            iv[i] = 0x01;
        }
        return iv;
    }
    /**
     * Encrypt the value with the encryption standard.
     * 
     * @param value
     *            raw string
     * @param key
     *            in hex format
     * @param iv
     *            in hex format if exist
     * @param type
     * @return result in hex format
     */
    public static String encrypt(String value, String key, String iv, CryptType type) {
        byte[] dvalue;
        try {
            dvalue = value.getBytes("utf-8");
        } catch (UnsupportedEncodingException e) {
            throw new RuntimeException(e);
        }
        byte[] dkey = Codec.hexStringToByte(key);
        byte[] div = null;
        if (iv != null && iv.length() > 0) {
            div = Codec.hexStringToByte(iv);
        }
        byte[] result = encrypt(dvalue, dkey, div, type);
        return Codec.byteToHexString(result);
    }
    /**
     * Encrypt the value with the encryption standard.
     * 
     * <pre>
     * key must have the corresponding length.
     * 
     * if use cbc mode which need iv param, the iv must not be null,
     * and iv data length is 16 for aes, 8 for des
     * 
     * </pre>
     * 
     * @param value
     * @param key
     * @param iv
     * @return
     */
    public static byte[] encrypt(byte[] value, byte[] key, byte[] iv, CryptType type) {
        try {
            SecretKeySpec skeySpec = new SecretKeySpec(key, type.keyAlg);
            Cipher cipher = Cipher.getInstance(type.algorithm);
            IvParameterSpec ivparamSpec = null;
            if (iv != null) {
                ivparamSpec = new IvParameterSpec(iv);
            }
            cipher.init(Cipher.ENCRYPT_MODE, skeySpec, ivparamSpec);
            return cipher.doFinal(value);
        } catch (Exception ex) {
            throw new RuntimeException(ex);
        }
    }
    /**
     * Encrypt the value with the encryption standard.
     * 
     * @param value
     *            encoded data in hex format
     * @param key
     *            in hex format
     * @param iv
     *            in hex format if exist
     * @param type
     * @return result raw string
     */
    public static String decrypt(String value, String key, String iv, CryptType type) {
        byte[] dvalue = Codec.hexStringToByte(value);
        byte[] dkey = Codec.hexStringToByte(key);
        byte[] div = null;
        if (iv != null && iv.length() > 0) {
            div = Codec.hexStringToByte(iv);
        }
        byte[] result = decrypt(dvalue, dkey, div, type);
        try {
            return new String(result, "utf-8");
        } catch (UnsupportedEncodingException e) {
            throw new RuntimeException(e);
        }
    }
    /**
     * Decrypt the value with the encryption standard.
     * 
     * <pre>
     * key must have the corresponding length.
     * 
     * if use cbc mode which need iv param, the iv must not be null,
     * and iv data length is 16 for aes, 8 for des
     * 
     * </pre>
     * 
     * @param value
     * @param key
     * @param iv
     * @param type
     * @return
     */
    public static byte[] decrypt(byte[] value, byte[] key, byte[] iv, CryptType type) {
        try {
            SecretKeySpec skeySpec = new SecretKeySpec(key, type.keyAlg);
            Cipher cipher = Cipher.getInstance(type.algorithm);
            IvParameterSpec ivparamSpec = null;
            if (iv != null) {
                ivparamSpec = new IvParameterSpec(iv);
            }
            cipher.init(Cipher.DECRYPT_MODE, skeySpec, ivparamSpec);
            return cipher.doFinal(value);
        } catch (Exception ex) {
            throw new RuntimeException(ex);
        }
    }
}

Exception in thread "main" java.security.InvalidKeyException: Illegal key size or default parameters