InvalidKeyException java.security.InvalidKeyException：没有安装的提供程序支持这个键：（空）

InvalidKeyException java.security.InvalidKeyException: No installed provider supports this key: (null)

提问by Deyaa

I have two classes, one is main class and another is the implementation of AES.

我有两个类，一个是主类，另一个是 AES 的实现。

However, in my AES class i have a method to decrypt a string, but whenever i run it, it gives an exception

但是，在我的 AES 类中，我有一种解密字符串的方法，但是每当我运行它时，它都会出现异常

My encryption method works just fine but my decryption method doesn't work as expected.

我的加密方法工作正常，但我的解密方法没有按预期工作。

The code

代码

private Cipher aesCipherForDecryption;
String strDecryptedText = new String();

public String decryptAES(final String ciphertext) {

    try {

        aesCipherForDecryption = Cipher.getInstance("AES/CBC/PKCS5PADDING");
        aesCipherForDecryption.init(Cipher.DECRYPT_MODE, secretKey, new IvParameterSpec(iV));
        byte[] byteDecryptedText = aesCipherForDecryption.doFinal(byteCipherText);
        strDecryptedText = new String(byteDecryptedText);

    } catch (IllegalBlockSizeException e) {
        System.out.print("IllegalBlockSizeException " +e);
    } catch (BadPaddingException e) {
        System.out.print("BadPaddingException "+e);
    } catch (NoSuchAlgorithmException e) {
        System.out.print("NoSuchAlgorithmException "+ e);
    } catch (NoSuchPaddingException e) {
        System.out.print("NoSuchPaddingException "+e);
    } catch (InvalidKeyException e) {
        System.out.print("InvalidKeyException "+e);
    } catch (InvalidAlgorithmParameterException e) {
        System.out.print("InvalidAlgorithmParameterException "+e);
    }

    System.out.println("\nDecrypted Text message is " + strDecryptedText);
    return strDecryptedText;
}

The error this method outputs is

此方法输出的错误是

InvalidKeyException java.security.InvalidKeyException: No installed provider supports this key: (null)

InvalidKeyException java.security.InvalidKeyException：没有安装的提供程序支持这个键：（空）

UPDATE #1:

更新#1：

So i have updated the code as the following

所以我更新了代码如下

public String decryptAES(byte[] ciphertext) {
    String strDecryptedText = new String();
        try {
            byte[] byteDecryptedText = aesCipherForDecryption.doFinal(ciphertext);

            strDecryptedText = new String(byteDecryptedText);

        } catch (IllegalBlockSizeException e) {
            System.out.print("IllegalBlockSizeException "+e);
            e.printStackTrace();
        } catch (BadPaddingException e) {
            System.out.print("BadPaddingException "+e);
            e.printStackTrace();
        }

    System.out.println("\nDecrypted Text message is " + strDecryptedText);
    return strDecryptedText;
}    

and in the main class i have this line

在主班我有这条线

byte [] byteciphertext = ciphertext.getBytes();

just to convert the string to bytes

只是将字符串转换为字节

is it correct? i'm still having

这是正确的吗？我还有

IllegalBlockSizeException javax.crypto.IllegalBlockSizeException: Input length must be multiple of 16 when decrypting with padded cipherjavax.crypto.IllegalBlockSizeException: Input length must be multiple of 16 when decrypting with padded cipher

Could someone help me fix this issue?

有人可以帮我解决这个问题吗？

Thank you.

谢谢你。

回答by user207421

secretKeyis clearly null.

secretKey很明显 null.

Other problems:

其他问题：

• You aren't using the input parameter cipherText.
• The input parameter cipherTextshould be a byte[],not a String: cipher text is binary, and Stringis not a container for binary data.
• The result string strDecryptedTextshould be a local variable, not a member variable.

• 您没有使用输入参数cipherText。
• 输入参数cipherText应该是一个byte[],not a String：密文是二进制的，String不是二进制数据的容器。
• 结果字符串strDecryptedText应该是局部变量，而不是成员变量。