Question

我找到了一些使用java KeyPairGenerator生成RSA Key Pais的示例。但我正在寻找的是一种使用现有RSA密钥对来加密/解密消息的方法。例如，我可以在eclipse中生成SSH2密钥对，我可以将其用于不同的事情（例如，签名maven artefacts，access git ....）

但我发现没有java示例如何加载我的私有（密码保护）RSA密钥并加密/解密消息。

我该怎么做？任何人都可以给我一个简单的例子。

这是一个公钥示例：

SSH-RSA AAAAB3NzaC1yc2EAAAADAQABAAAAgQCYUsJ8cqtZD + / hJRl5Pq6k7139hjpNKdrHzB / vndcFq1aLS3da2iS0BZu17FS + RwVIj29aFwmdqh0OSck648yZC5O79Uf2k / tT6Nx1z7P7KCWJTQ9zrd9t ++ Ox6RWzkIgj4q5oq8P / S6P / 3f1NeG2SZoPrWpRojQsWl8LPqdVTvQ == RSA-1024

Answer 1

Here有一个很好的RSA加密示例。

package in.javadigest.encryption;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.NoSuchAlgorithmException;
import java.security.PrivateKey;
import java.security.PublicKey;

import javax.crypto.Cipher;

/**
 * @author JavaDigest
 * 
 */
public class EncryptionUtil {

  /**
   * String to hold name of the encryption algorithm.
   */
  public static final String ALGORITHM = "RSA";

  /**
   * String to hold the name of the private key file.
   */
  public static final String PRIVATE_KEY_FILE = "C:/keys/private.key";

  /**
   * String to hold name of the public key file.
   */
  public static final String PUBLIC_KEY_FILE = "C:/keys/public.key";

  /**
   * Generate key which contains a pair of private and public key using 1024
   * bytes. Store the set of keys in Prvate.key and Public.key files.
   * 
   * @throws NoSuchAlgorithmException
   * @throws IOException
   * @throws FileNotFoundException
   */
  public static void generateKey() {
    try {
      final KeyPairGenerator keyGen = KeyPairGenerator.getInstance(ALGORITHM);
      keyGen.initialize(1024);
      final KeyPair key = keyGen.generateKeyPair();

      File privateKeyFile = new File(PRIVATE_KEY_FILE);
      File publicKeyFile = new File(PUBLIC_KEY_FILE);

      // Create files to store public and private key
      if (privateKeyFile.getParentFile() != null) {
        privateKeyFile.getParentFile().mkdirs();
      }
      privateKeyFile.createNewFile();

      if (publicKeyFile.getParentFile() != null) {
        publicKeyFile.getParentFile().mkdirs();
      }
      publicKeyFile.createNewFile();

      // Saving the Public key in a file
      ObjectOutputStream publicKeyOS = new ObjectOutputStream(
          new FileOutputStream(publicKeyFile));
      publicKeyOS.writeObject(key.getPublic());
      publicKeyOS.close();

      // Saving the Private key in a file
      ObjectOutputStream privateKeyOS = new ObjectOutputStream(
          new FileOutputStream(privateKeyFile));
      privateKeyOS.writeObject(key.getPrivate());
      privateKeyOS.close();
    } catch (Exception e) {
      e.printStackTrace();
    }

  }

  /**
   * The method checks if the pair of public and private key has been generated.
   * 
   * @return flag indicating if the pair of keys were generated.
   */
  public static boolean areKeysPresent() {

    File privateKey = new File(PRIVATE_KEY_FILE);
    File publicKey = new File(PUBLIC_KEY_FILE);

    if (privateKey.exists() && publicKey.exists()) {
      return true;
    }
    return false;
  }

  /**
   * Encrypt the plain text using public key.
   * 
   * @param text
   *          : original plain text
   * @param key
   *          :The public key
   * @return Encrypted text
   * @throws java.lang.Exception
   */
  public static byte[] encrypt(String text, PublicKey key) {
    byte[] cipherText = null;
    try {
      // get an RSA cipher object and print the provider
      final Cipher cipher = Cipher.getInstance(ALGORITHM);
      // encrypt the plain text using the public key
      cipher.init(Cipher.ENCRYPT_MODE, key);
      cipherText = cipher.doFinal(text.getBytes());
    } catch (Exception e) {
      e.printStackTrace();
    }
    return cipherText;
  }

  /**
   * Decrypt text using private key.
   * 
   * @param text
   *          :encrypted text
   * @param key
   *          :The private key
   * @return plain text
   * @throws java.lang.Exception
   */
  public static String decrypt(byte[] text, PrivateKey key) {
    byte[] dectyptedText = null;
    try {
      // get an RSA cipher object and print the provider
      final Cipher cipher = Cipher.getInstance(ALGORITHM);

      // decrypt the text using the private key
      cipher.init(Cipher.DECRYPT_MODE, key);
      dectyptedText = cipher.doFinal(text);

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

    return new String(dectyptedText);
  }

  /**
   * Test the EncryptionUtil
   */
  public static void main(String[] args) {

    try {

      // Check if the pair of keys are present else generate those.
      if (!areKeysPresent()) {
        // Method generates a pair of keys using the RSA algorithm and stores it
        // in their respective files
        generateKey();
      }

      final String originalText = "Text to be encrypted ";
      ObjectInputStream inputStream = null;

      // Encrypt the string using the public key
      inputStream = new ObjectInputStream(new FileInputStream(PUBLIC_KEY_FILE));
      final PublicKey publicKey = (PublicKey) inputStream.readObject();
      final byte[] cipherText = encrypt(originalText, publicKey);

      // Decrypt the cipher text using the private key.
      inputStream = new ObjectInputStream(new FileInputStream(PRIVATE_KEY_FILE));
      final PrivateKey privateKey = (PrivateKey) inputStream.readObject();
      final String plainText = decrypt(cipherText, privateKey);

      // Printing the Original, Encrypted and Decrypted Text
      System.out.println("Original Text: " + originalText);
      System.out.println("Encrypted Text: " +cipherText.toString());
      System.out.println("Decrypted Text: " + plainText);

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

如何在Java中使用带密码的RSA密钥

1 个答案: