加密PHP,解密Java

Question

我在php中有一个web服务,它生成一个用于加密消息的密钥对,以及一个用于检索私钥并解密消息的java应用程序.

对于php我正在使用http://phpseclib.sourceforge.net/并拥有这两个文件:

keypair.php

<?php

set_time_limit(0);
if( file_exists('private.key') )
{
    echo file_get_contents('private.key');
}
else
{
    include('Crypt/RSA.php');
    $rsa = new Crypt_RSA();
    $rsa->createKey();
    $res = $rsa->createKey();

    $privateKey = $res['privatekey'];
    $publicKey  = $res['publickey'];

    file_put_contents('public.key', $publicKey);
    file_put_contents('private.key', $privateKey);
}

?>

encrypt.php

<?php

include('Crypt/RSA.php');

//header("Content-type: text/plain");

set_time_limit(0);
$rsa = new Crypt_RSA();
$rsa->setEncryptionMode(CRYPT_RSA_ENCRYPTION_OAEP);
$rsa->loadKey(file_get_contents('public.key')); // public key

$plaintext = 'Hello World!';
$ciphertext = $rsa->encrypt($plaintext);

echo base64_encode($ciphertext);

?>

在java中我有这个代码:

package com.example.app;

import java.io.DataInputStream;
import java.net.URL;
import java.security.Security;

import javax.crypto.Cipher;
import javax.crypto.spec.SecretKeySpec;

import sun.misc.BASE64Decoder;

public class MainClass {

    /**
     * @param args
     */
    public static void main(String[] args)
    {
        Security.addProvider(new org.bouncycastle.jce.provider.BouncyCastleProvider());

        try {
            BASE64Decoder decoder   = new BASE64Decoder();
            String b64PrivateKey    = getContents("http://localhost/api/keypair.php").trim();
            String b64EncryptedStr  = getContents("http://localhost/api/encrypt.php").trim();

            System.out.println("PrivateKey (b64): " + b64PrivateKey);
            System.out.println(" Encrypted (b64): " + b64EncryptedStr);

            SecretKeySpec privateKey    = new SecretKeySpec( decoder.decodeBuffer(b64PrivateKey) , "AES");
            Cipher cipher               = Cipher.getInstance("RSA/None/OAEPWithSHA1AndMGF1Padding", "BC");
            cipher.init(Cipher.DECRYPT_MODE, privateKey);

            byte[] plainText            = decoder.decodeBuffer(b64EncryptedStr);

            System.out.println("         Message: " + plainText);
        }
        catch( Exception e )
        {
            System.out.println("           Error: " + e.getMessage());
        }

    }

    public static String getContents(String url)
    {
        try {
            String result = "";
            String line;
            URL u = new URL(url);
            DataInputStream theHTML = new DataInputStream(u.openStream());
            while ((line = theHTML.readLine()) != null)
                result = result + "\n" + line;

            return result;
        }
        catch(Exception e){}

        return "";
    }
}

我的问题是:

1. 为什么我有一个例外说"不是RSA密钥!"？
2. 我该如何改进这段代码？我使用base64来避免Java和PHP之间的编码和通信错误.
3. 这个概念是对的吗？我的意思是,我正确使用它？

Answer 1

在上述答案的帮助下，我发现 SecretKeySpec 使用错误，并且我发现来自 OpenSSL 的 PEM 文件不是“标准格式”，因此我需要使用 PEMReader 将其转换为 PrivateKey 类。

这是我的工人阶级：

package com.example.app;

import java.io.BufferedReader;
import java.io.DataInputStream;
import java.io.StringReader;
import java.net.URL;
import java.security.KeyPair;
import java.security.PrivateKey;
import java.security.Security;

import javax.crypto.Cipher;

import org.bouncycastle.openssl.PEMReader;

import sun.misc.BASE64Decoder;

public class MainClass {

    /**
     * @param args
     */
    public static void main(String[] args)
    {
        Security.addProvider(new org.bouncycastle.jce.provider.BouncyCastleProvider());

        try {
            BASE64Decoder decoder   = new BASE64Decoder();
            String b64PrivateKey    = getContents("http://localhost/api/keypair.php").trim();
            String b64EncryptedStr  = getContents("http://localhost/api/encrypt.php").trim();

            System.out.println("PrivateKey (b64): " + b64PrivateKey);
            System.out.println(" Encrypted (b64): " + b64EncryptedStr);

            byte[] decodedKey           = decoder.decodeBuffer(b64PrivateKey);
            byte[] decodedStr           = decoder.decodeBuffer(b64EncryptedStr);
            PrivateKey privateKey       = strToPrivateKey(new String(decodedKey));

            Cipher cipher               = Cipher.getInstance("RSA/None/OAEPWithSHA1AndMGF1Padding", "BC");
            cipher.init(Cipher.DECRYPT_MODE, privateKey);


            byte[] plainText            = cipher.doFinal(decodedStr);

            System.out.println("         Message: " + new String(plainText));
        }
        catch( Exception e )
        {
            System.out.println("           Error: " + e.getMessage());
        }

    }

    public static String getContents(String url)
    {
        try {
            String result = "";
            String line;
            URL u = new URL(url);
            DataInputStream theHTML = new DataInputStream(u.openStream());
            while ((line = theHTML.readLine()) != null)
                result = result + "\n" + line;

            return result;
        }
        catch(Exception e){}

        return "";
    }

    public static PrivateKey strToPrivateKey(String s)
    {
        try {
            BufferedReader br   = new BufferedReader( new StringReader(s) );
            PEMReader pr        = new PEMReader(br);
            KeyPair kp          = (KeyPair)pr.readObject();
            pr.close();
            return kp.getPrivate();
        }
        catch( Exception e )
        {

        }

        return null;
    }
}

这是我的 keypair.php

<?php

set_time_limit(0);
if( file_exists('private.key') )
{
    echo base64_encode(file_get_contents('private.key'));
}
else
{
    include('Crypt/RSA.php');

    $rsa = new Crypt_RSA();
    $rsa->setHash('sha1');
    $rsa->setMGFHash('sha1');
    $rsa->setEncryptionMode(CRYPT_RSA_ENCRYPTION_OAEP);
    $rsa->setPrivateKeyFormat(CRYPT_RSA_PRIVATE_FORMAT_PKCS1);
    $rsa->setPublicKeyFormat(CRYPT_RSA_PUBLIC_FORMAT_PKCS1);

    $res = $rsa->createKey(1024);

    $privateKey = $res['privatekey'];
    $publicKey  = $res['publickey'];

    file_put_contents('public.key', $publicKey);
    file_put_contents('private.key', $privateKey);

    echo base64_encode($privateKey);
}

?>

和我的 encrypt.php

<?php
    include('Crypt/RSA.php');
    set_time_limit(0);

    $rsa = new Crypt_RSA();
    $rsa->setHash('sha1');
    $rsa->setMGFHash('sha1');
    $rsa->setEncryptionMode(CRYPT_RSA_ENCRYPTION_OAEP);

    $rsa->loadKey(file_get_contents('public.key')); // public key

    $plaintext  = 'Hello World!';
    $ciphertext = $rsa->encrypt($plaintext);
    $md5        = md5($ciphertext);
    file_put_contents('md5.txt', $md5);
    file_put_contents('encrypted.txt', base64_encode($ciphertext));

    echo base64_encode($ciphertext);

?>

我希望它对任何人都有帮助，谢谢。