KeyPairGenerator不可用

Question

我正在创建一个生成密钥对的程序，但我有这个错误：

Exception in thread "main" java.lang.NullPointerException
at generateAESKey.main(generateAESKey.java:43)

这是我目前的工作。

  

key.getEncoded（））;

未被阅读。

public class generateAESKey {
    public static void main(String[] args) throws Exception {
        generateAESKey generatekey = new generateAESKey();    
        KeyGenerator keyGen = KeyGenerator.getInstance("AES");
        keyGen.init(256);
        SecretKey skey = keyGen.generateKey();
        byte[] raw = skey.getEncoded();
        FileOutputStream fos2 = new FileOutputStream("C:\\Users\\win8.1\\Desktop\\AES\\test.txt");
        fos2.write(raw);
        fos2.close();


        KeyPairGenerator keyGen1 = KeyPairGenerator.getInstance("RSA");
        SecureRandom random = SecureRandom.getInstance("SHA1PRNG", "SUN");
        keyGen1.initialize(1024, random);
        KeyPair generatedKeyPair = keyGen1.genKeyPair();
        savePublicKey(generatedKeyPair.getPublic(), "C:\\Users\\win8.1\\Desktop\\AES\\public");
        savePrivateKey(generatedKeyPair.getPrivate(), "C:\\Users\\win8.1\\Desktop\\AES\\private");


        PublicKey key = null;

        X509EncodedKeySpec x509EncodedKeySpec = new X509EncodedKeySpec(
        key.getEncoded());
        FileOutputStream fos3 = new FileOutputStream("C:\\Users\\win8.1\\Desktop\\AES\\public.txt");
        fos3.write(x509EncodedKeySpec.getEncoded());
        fos3.close();

        PrivateKey key1 = null;
        PKCS8EncodedKeySpec pkcs8EncodedKeySpec = new PKCS8EncodedKeySpec(
        key1.getEncoded());
        FileOutputStream fos4 = new FileOutputStream("C:\\Users\\win8.1\\Desktop\\AES\\private.txt");
        fos4.write(pkcs8EncodedKeySpec.getEncoded());
        fos4.close();
        System.out.println("SAVE");

    }
        private static void savePrivateKey(PrivateKey private1, String string) {
        // TODO Auto-generated method stub

    }
        private static void savePublicKey(PublicKey public1, String string) {
        // TODO Auto-generated method stub

    }

        public SecretKeySpec getKeySpec() throws IOException, NoSuchAlgorithmException {
            byte[] bytes = new byte[16];
            File f = new File("aes.key");
            SecretKey key = null;
            SecretKeySpec spec = null;
            if (f.exists()) {
              new FileInputStream(f).read(bytes);
            } else {
               KeyGenerator kgen = KeyGenerator.getInstance("AES");
               kgen.init(256);  //128 kalagay
               key = kgen.generateKey();
               bytes = key.getEncoded();
               new FileOutputStream(f).write(bytes);
            }
            spec = new SecretKeySpec(bytes,"AES");
            return spec;
          }
}

任何帮助将不胜感激。谢谢。

我已经编辑过了。

Answer 1

第一个错误：KeyPairGenerator.getInstance(String algorithm)只能处理以下输入String：

• DiffieHellman
• DSA
• RSA
• EC

对于mor infos look in the docs

可能的电话 KeyPairGenerator.getInstance("RSA");

第二个错误（nullptr）： 你必须创建一个PublicKey！你正在做PublicKey key = null;然后你堕落：

X509EncodedKeySpec x509EncodedKeySpec = new X509EncodedKeySpec(
key.getEncoded());//key is null so nullpointer will occur

您必须为key变量指定一个值。我假设您想要创建PublicKey，所以： PublicKey key = generatedKeyPair.getPublic();

Answer 2

这一行错了：

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  <h1> Paintings </h1>

  <img src="images/painting 2.png" id="main-painting2">

  <div class="second-row-images">
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</div>

您必须提供要使用的算法的名称，例如：

KeyPairGenerator keyGen1 = KeyPairGenerator.getInstance("ALGORITHM");