java - aes 加密给出错误，因为 iv 应该是 16 字节长

Question

我正在尝试加密一个接近 40 到 50 个字符长的整数值。我正在使用 AES 加密，但它给了我错误，因为整数值应该是 16 字节长。请参阅下面我的代码:

public class MCrypt {

private String iv ;//Dummy iv (CHANGE IT!)
private IvParameterSpec ivspec;
private SecretKeySpec keyspec;
private Cipher cipher;

private String SecretKey = "khaleed";//Dummy secretKey (CHANGE IT!)

public MCrypt(String firstpar1)
{
    iv=firstpar1;//firstpar1 can be aroung 40-50 characters long

        ivspec = new IvParameterSpec(iv.getBytes());

        keyspec = new SecretKeySpec(SecretKey.getBytes(), "AES");

        try {
                cipher = Cipher.getInstance("AES/CBC/NoPadding");
        } catch (NoSuchAlgorithmException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
        } catch (NoSuchPaddingException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
        }
        System.out.println(6666);
}

public byte[] encrypt(String text) throws Exception
{
        if(text == null || text.length() == 0)
                throw new Exception("Empty string");

        byte[] encrypted = null;

        try {
                cipher.init(Cipher.ENCRYPT_MODE, keyspec, ivspec);

                encrypted = cipher.doFinal(padString(text).getBytes());
        } catch (Exception e)
        {                       
                throw new Exception("[encrypt] " + e.getMessage());
        }

        return encrypted;
}

public byte[] decrypt(String code) throws Exception
{
        if(code == null || code.length() == 0)
                throw new Exception("Empty string");

        byte[] decrypted = null;

        try {
                cipher.init(Cipher.DECRYPT_MODE, keyspec, ivspec);

                decrypted = cipher.doFinal(hexToBytes(code));
        } catch (Exception e)
        {
                throw new Exception("[decrypt] " + e.getMessage());
        }
        return decrypted;
}



public static String bytesToHex(byte[] data)
{
        if (data==null)
        {
                return null;
        }

        int len = data.length;
        String str = "";
        for (int i=0; i<len; i++) {
                if ((data[i]&0xFF)<16)
                        str = str + "0" + java.lang.Integer.toHexString(data[i]&0xFF);
                else
                        str = str + java.lang.Integer.toHexString(data[i]&0xFF);
        }
        return str;
}


public static byte[] hexToBytes(String str) {
        if (str==null) {
                return null;
        } else if (str.length() < 2) {
                return null;
        } else {
                int len = str.length() / 2;
                byte[] buffer = new byte[len];
                for (int i=0; i<len; i++) {
                        buffer[i] = (byte) Integer.parseInt(str.substring(i*2,i*2+2),16);
                }
                return buffer;
        }
}



private static String padString(String source)
{
  char paddingChar = ' ';
  int size = 16;
  int x = source.length() % size;
  int padLength = size - x;

  for (int i = 0; i < padLength; i++)
  {
          source += paddingChar;
  }

  return source;
}
}

任何建议都会很棒。

Answer 1

不要创建自己的填充，使用“PKCS5Padding”而不是“NoPadding”。确保您的(字符)编码符合规范，并且您的 IV 是随机的、 block 大小的并且包含在密文中。如果您的 key 是字符串，请使用基于密码的加密。