Question

作为项目实施的一部分，我做了以下事情： 1. Generete DSA密钥 2.使用AES加密私钥 3.保存到文件中 4.打开文件并阅读加密的私钥 5.我试图将读取值转换为主键格式，但错误来自此处。我在这里附上上述步骤的代码：

public class Pgm {
public static void main(String[] args) { 
try {
            KeyPairGenerator dsa =  KeyPairGenerator.getInstance("DSA");
            SecureRandom random = new SecureRandom();
            dsa.initialize(1024, random);
            KeyPair keypair = dsa.generateKeyPair();
            PrivateKey privateKey = (PrivateKey) keypair.getPrivate();
            byte[] key = "�u���1Ù�iw&a".getBytes();
            Key aesKey = new SecretKeySpec(key, "AES");
            Cipher cipher = Cipher.getInstance("AES");
            String currentDir = System.getProperty("user.dir"); 
            // encrypt the text
            cipher.init(Cipher.ENCRYPT_MODE, aesKey);
            byte[] abc = privateKey.getEncoded();

            byte[] encrypted = cipher.doFinal(abc);
            // System.out.println("len="+encrypted.length());
            File dir=new File(currentDir);
            File private_file=new File(dir,"privatekey.txt");
            if(!private_file.exists()){
                private_file.createNewFile();
            }
            FileOutputStream fileos = new FileOutputStream(private_file); 
            ObjectOutputStream objectos = new ObjectOutputStream(fileos);
            objectos.writeObject(encrypted);
            objectos.close();
            fileos.close();

            File file_private = new File(dir,"privatekey.txt");
            FileInputStream fileo = new FileInputStream(file_private); 
            ObjectInputStream objos = new ObjectInputStream(fileo);
            Object obj = objos.readObject();
            byte[] encrypted1= (byte[] )obj;
            cipher.init(Cipher.DECRYPT_MODE, aesKey);
            String decrypted = new String(cipher.doFinal(encrypted1));
            if (decrypted.equals(new String(abc)))
               System.out.println("true");
            else
               System.out.println("false");
            Signature tosign = Signature.getInstance("DSA");
            byte[] val =  decrypted.getBytes();
            PrivateKey privatekey1 = (PrivateKey)val;
            tosign.initSign(privatekey1);   

      }
      catch(Exception e)
      {
            e.printStackTrace();
      }
  }

}

＆＃39; PrivateKey privatekey1 = (PrivateKey)val;

将错误显示为不可转换的类型

Answer 1

您无法简单地将字节数组转换为PrivateKey实例。您可以按KeyFactory

生成密钥

Answer 2

如果用此替换显式转换怎么办：

PrivateKey privateKey1 = keyFactory.generatePrivate(new PKCS8EncodedKeySpec(val));

如何将字节数组转换为DSA私钥？

2 个答案: