如何在Java中使用RSA密钥进行加密解密

Question

我需要用由openssl生成的rsaprivatekey.pem和rsapublickey.pem密钥，将Unix代码中的加密和解密步骤替换为Java代码。

我生成了这些密钥。

openssl  genrsa  -out /tmp/rsaprivatekey.pem  -des3 1024
openssl rsa -in /tmp/rsaprivatekey.pem -pubout -out /tmp/rsapublickey.pem

我在Unix中使用键（现在需要在Java中实现）

echo "Text to encript"| openssl rsautl -encrypt -inkey /tmp/rsapublickey.pem -pubin -out out.enc
openssl rsautl -decrypt -inkey /tmp/rsaprivatekey.pem -in out.enc

这是我尝试去做它的结果

public static void main(String[] args) {


    Base64 base64 = new Base64();

    String TextStream = "this is the input text";
    byte[] Cipher;
    System.out.println("input:\n" + TextStream);
    Cipher = encrypt(TextStream);
    System.out.println("cipher:\n" + base64.encodeAsString(Cipher));
    System.out.println("decrypt:\n" + decrypt(Cipher));
}

private static byte[] encrypt(String Buffer) {
    try {

        Cipher rsa;
        rsa = Cipher.getInstance("RSA");
        rsa.init(Cipher.ENCRYPT_MODE, getPrivateKey(PRIVATE_PATH));
        return rsa.doFinal(Buffer.getBytes());
    } catch (Exception e) {
        e.printStackTrace();
    }
    return null;
}


private static String decrypt(byte[] buffer) {
    try {
        Cipher rsa;
        rsa = Cipher.getInstance("RSA");
        rsa.init(Cipher.DECRYPT_MODE, getPrivateKey(PUBLIC_PATH));
        byte[] utf8 = rsa.doFinal(buffer);
        return new String(utf8, "UTF8");
    } catch (Exception e) {
        e.printStackTrace();
    }
    return null;
}

public static PrivateKey getPrivateKey(String filename) throws Exception {
    File f = new File(filename);
    FileInputStream fis = new FileInputStream(f);
    DataInputStream dis = new DataInputStream(fis);
    byte[] keyBytes = new byte[(int) f.length()];
    dis.readFully(keyBytes);
    dis.close();

    PKCS8EncodedKeySpec spec = new PKCS8EncodedKeySpec(keyBytes);
    KeyFactory kf = KeyFactory.getInstance("RSA");
    return kf.generatePrivate(spec);
}

public static PublicKey getPublicKey(String filename) throws Exception {
    File f = new File(filename);
    FileInputStream fis = new FileInputStream(f);
    DataInputStream dis = new DataInputStream(fis);
    byte[] keyBytes = new byte[(int) f.length()];
    dis.readFully(keyBytes);
    dis.close();

    X509EncodedKeySpec spec = new X509EncodedKeySpec(keyBytes);
    KeyFactory kf = KeyFactory.getInstance("RSA");
    return kf.generatePublic(spec);
}

但它不起作用，PKCS8EncodedKeySpec / X509EncodedKeySpec 不正确...但我不知道该放什么

- caeycae

---

Stack Overflow不是读心术。 - Matt Ball

关于我正在准备我的水晶球 - ant

还可以参见以下内容：如何在Java中使用RSA密钥进行加密解密，Java中与OpenSSL命令等效的方法，如何在Java中使用RSA密钥进行加密解密，会话密钥的OpenSSL加密。 - jww

Answer 1

解决方案：

感谢 @Sanjeev，使用Bouncy Castle API，我能够使用由OpenSSL生成的密钥进行加密/解密操作。

public static void main(String[] args) throws IOException {

    Security.addProvider(new BouncyCastleProvider());

    KeyPair keyPair = readKeyPair(new File(PRIVATE_PATH), "pass"); 
    // if the private key is not encripted, pass can be anything.
    Key publickey = readPublicKey(new File(PUBLIC_PATH), "pass"); 
    Base64 base64 = new Base64();
    String text = "this is the input text";
    byte[] encripted;
    System.out.println("input:\n" + text);
    encripted = encrypt(keyPair.getPublic(), text);
    System.out.println("cipher:\n" + base64.encodeAsString(encripted));
    System.out.println("decrypt:\n" + decrypt(keyPair.getPrivate(), encripted));        
}

private static byte[] encrypt(Key pubkey, String text) {
    try {
        Cipher rsa;
        rsa = Cipher.getInstance("RSA");
        rsa.init(Cipher.ENCRYPT_MODE, pubkey);
        return rsa.doFinal(text.getBytes());
    } catch (Exception e) {
        e.printStackTrace();
    }
    return null;
}


private static String decrypt(Key decryptionKey, byte[] buffer) {
    try {
        Cipher rsa;
        rsa = Cipher.getInstance("RSA");
        rsa.init(Cipher.DECRYPT_MODE, decryptionKey);
        byte[] utf8 = rsa.doFinal(buffer);
        return new String(utf8, "UTF8");
    } catch (Exception e) {
        e.printStackTrace();
    }
    return null;
}

private static KeyPair readKeyPair(File privateKey, String keyPassword) throws IOException {
    FileReader fileReader = new FileReader(privateKey);
    PEMReader r = new PEMReader(fileReader, new DefaultPasswordFinder(keyPassword.toCharArray()));
    try {
        return (KeyPair) r.readObject();
    } catch (IOException ex) {
        throw ex;
    } finally {
        r.close();
        fileReader.close();
    }
}

private static Key readPublicKey(File privateKey, String keyPassword) throws IOException {
    FileReader fileReader = new FileReader(privateKey);
    PEMReader r = new PEMReader(fileReader, new DefaultPasswordFinder(keyPassword.toCharArray()));
    try {
        return (RSAPublicKey) r.readObject();
    } catch (IOException ex) {
        throw ex;
    } finally {
        r.close();
        fileReader.close();
    }
}

- caeycae

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应该是“UTF-8”吧？ - drew

你好 @caeycae，我正在关注你的帖子，我也遇到了类似的问题。DefaultPasswordFinder在哪个JAR / Library中？请帮我确认一下。 - danisupr4

你找到了DefaultPasswordFinder需要包含的jar文件的解决方案吗？ - sasi

私有静态类DefaultPasswordFinder实现了PasswordFinder接口 { private final char[] password; DefaultPasswordFinder(char[] password) { this.password = password; } @Override public char[] getPassword() { return password; } } - Vladimir Panteleev

Answer 2

我觉得你在读取PEM文件时遇到了问题。 JPA不直接支持PEM格式。 你有两个选择，要么将它们转换为DER编码的文件（你可以使用openSSL来完成），要么你可以使用bouncy castle API来读取（或写入）PEM文件。 你可能会感兴趣的类名叫做PEMReader（也可能是PEMWriter）。 在bouncycastle网站上这里是关于Javadoc的链接。

- Sanjeev

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上面的Javadoc链接已经失效了，当前的链接在这里。 - MikeF