问题
As a part of project implementation,I have done: 1. Generete DSA keys 2. Encrypt the private key using AES 3. Save into the file 4. Open the file and read the encrypted private key 5. I tried to convert the read value into primary key format
import java.security.spec.EncodedKeySpec;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.Security;
import java.io.File;
import java.security.KeyFactory;
import java.security.PrivateKey;
import java.security.Signature;
import java.security.spec.PKCS8EncodedKeySpec;
import java.io.*;
import java.security.*;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.spec.SecretKeySpec;
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���1�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();
KeyFactory generator = KeyFactory.getInstance("DSA");
EncodedKeySpec privateKeySpec = new PKCS8EncodedKeySpec(val);
PrivateKey privatekey1 = generator.generatePrivate(privateKeySpec);
tosign.initSign(privatekey1);
} catch (Exception e) {
System.out.println("failed");
e.printStackTrace();
}
}
}
While I am trying to execute the above code, it shows the following error!
回答1:
Ciphertext and keys should both consist of random bytes. Neither one of them can be represented 1:1 with a string. Not all bytes may represent valid encodings for a specific character-encoding.
Instead you should use byte arrays directly. If you require actual text, use either hexadecimals or base 64 encoding.
Your code using ciphertext as bytes and a key specified in hexadecimals:
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.security.Key;
import java.security.KeyFactory;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.PrivateKey;
import java.security.SecureRandom;
import java.security.Signature;
import java.security.spec.EncodedKeySpec;
import java.security.spec.PKCS8EncodedKeySpec;
import java.util.Arrays;
import javax.crypto.Cipher;
import javax.crypto.spec.SecretKeySpec;
import codec.Hex;
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 = Hex.decode("000102030405060708090A0B0C0D0E0F");
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);
byte[] decrypted = cipher.doFinal(encrypted1);
if (Arrays.equals(decrypted, abc))
System.out.println("true");
else
System.out.println("false");
Signature tosign = Signature.getInstance("DSA");
KeyFactory generator = KeyFactory.getInstance("DSA");
EncodedKeySpec privateKeySpec = new PKCS8EncodedKeySpec(decrypted);
PrivateKey privatekey1 = generator.generatePrivate(privateKeySpec);
tosign.initSign(privatekey1);
} catch (Exception e) {
System.out.println("failed");
e.printStackTrace();
}
}
}
来源：https://stackoverflow.com/questions/26867840/java-security-spec-invalidkeyspecexception-and-inappropriate-key-specification-e