C# Java间进行RSA加密解密交互（二）

接着前面一篇文章C# Java间进行RSA加密解密交互，继续探讨这个问题。

在前面，虽然已经实现了C# Java间进行RSA加密解密交互，但是还是与项目中要求的有所出入。在项目中，客户端（Java）的加密是通过这么一个方法实现的：

 

/**
 * RSA加密
 * @param text--待加密的明文
 * @param key--公钥，由服务器端提供的经base64编码的字符串
 * @return
 */
public static String RSAEncryptoWithPublicKey(String text, String key) {
    String result = null;
    try {
        byte[] publicKeyByte = base64Decrypto(key);

        X509EncodedKeySpec x509 = new X509EncodedKeySpec(publicKeyByte);
        KeyFactory keyFactory = KeyFactory.getInstance("RSA");
        PublicKey publicKey = keyFactory.generatePublic(x509);

        Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
        cipher.init(Cipher.ENCRYPT_MODE, publicKey);

        result = base64Encrypto(cipher.doFinal(text.getBytes()));
    } catch (Exception e) {
        e.printStackTrace();
        return null;
    }
    return result;
}

在上一篇中的实现，需要客户端先做一次解析工作，而已经开发好的客户端是没有这一层的，所以得想个办法，在服务器端（C#）完成这项工作。但是经过多次尝试，依然未果。于是换一种方式，密钥对不由C#提供，而转而有Java提供，生成客户端需要的公钥形式，并解析公钥私钥，组装C# 的XML格式的密钥对字符串。

 

下面贴一下RSA密钥对生成代码（参考RSA的密钥把JAVA格式转换成C#的格式）

 

import java.io.UnsupportedEncodingException;
import java.lang.reflect.Method;
import java.security.KeyFactory;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.NoSuchAlgorithmException;
import java.security.PublicKey;
import java.security.interfaces.RSAPrivateCrtKey;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import java.util.HashMap;

/**
 * @author Administrator
 *
 */
public class RSAJavaToCSharp {
    public static void main(String[] args) throws Exception {
        HashMap<String, Object> map = getKeys();
        RSAPublicKey publicKey = (RSAPublicKey) map.get("PUBLIC");
        RSAPrivateKey privateKey = (RSAPrivateKey) map.get("PRIVATE");

        String publicKeyString = getRSAPublicKeyAsNetFormat(publicKey.getEncoded());
        String privateKeyString = getRSAPrivateKeyAsNetFormat(privateKey.getEncoded());

        System.out.println(encodeBase64(publicKey.getEncoded()));//此处为客户端加密时需要的公钥字符串
        System.out.println(encodePublicKeyToXml(publicKey));
        System.out.println(publicKeyString);
        System.out.println(privateKeyString);
    }

    /**获取密钥对
     * @return
     * @throws NoSuchAlgorithmException
     */
    public static HashMap<String, Object> getKeys()
            throws NoSuchAlgorithmException {
        HashMap<String, Object> map = new HashMap<String, Object>();
        KeyPairGenerator keyPairGen = KeyPairGenerator.getInstance("RSA");
        keyPairGen.initialize(1024);
        KeyPair keyPair = keyPairGen.generateKeyPair();
        RSAPublicKey publicKey = (RSAPublicKey) keyPair.getPublic();
        RSAPrivateKey privateKey = (RSAPrivateKey) keyPair.getPrivate();
        map.put("PUBLIC", publicKey);
        map.put("PRIVATE", privateKey);
        return map;
    }

    /**
     * 私钥转换成C#格式
     * @param encodedPrivkey
     * @return
     */
    private static String getRSAPrivateKeyAsNetFormat(byte[] encodedPrivateKey) {
        try {
            StringBuffer buff = new StringBuffer(1024);

            PKCS8EncodedKeySpec pvkKeySpec = new PKCS8EncodedKeySpec(
                    encodedPrivateKey);
            KeyFactory keyFactory = KeyFactory.getInstance("RSA");
            RSAPrivateCrtKey pvkKey = (RSAPrivateCrtKey) keyFactory
                    .generatePrivate(pvkKeySpec);

            buff.append("<RSAKeyValue>");
            buff.append("<Modulus>"
                    + encodeBase64(removeMSZero(pvkKey.getModulus()
                            .toByteArray())) + "</Modulus>");

            buff.append("<Exponent>"
                    + encodeBase64(removeMSZero(pvkKey.getPublicExponent()
                            .toByteArray())) + "</Exponent>");

            buff.append("<P>"
                    + encodeBase64(removeMSZero(pvkKey.getPrimeP()
                            .toByteArray())) + "</P>");

            buff.append("<Q>"
                    + encodeBase64(removeMSZero(pvkKey.getPrimeQ()
                            .toByteArray())) + "</Q>");

            buff.append("<DP>"
                    + encodeBase64(removeMSZero(pvkKey.getPrimeExponentP()
                            .toByteArray())) + "</DP>");

            buff.append("<DQ>"
                    + encodeBase64(removeMSZero(pvkKey.getPrimeExponentQ()
                            .toByteArray())) + "</DQ>");

            buff.append("<InverseQ>"
                    + encodeBase64(removeMSZero(pvkKey.getCrtCoefficient()
                            .toByteArray())) + "</InverseQ>");

            buff.append("<D>"
                    + encodeBase64(removeMSZero(pvkKey.getPrivateExponent()
                            .toByteArray())) + "</D>");
            buff.append("</RSAKeyValue>");

            return buff.toString();
        } catch (Exception e) {
            System.err.println(e);
            return null;
        }
    }

    /**
     * 公钥转成C#格式
     * @param encodedPrivkey
     * @return
     */
    private static String getRSAPublicKeyAsNetFormat(byte[] encodedPublicKey) {
        try {
            StringBuffer buff = new StringBuffer(1024);

            //Only RSAPublicKeySpec and X509EncodedKeySpec supported for RSA public keys
            KeyFactory keyFactory = KeyFactory.getInstance("RSA");
            RSAPublicKey pukKey = (RSAPublicKey) keyFactory
                    .generatePublic(new X509EncodedKeySpec(encodedPublicKey));

            buff.append("<RSAKeyValue>");
            buff.append("<Modulus>"
                    + encodeBase64(removeMSZero(pukKey.getModulus()
                            .toByteArray())) + "</Modulus>");
            buff.append("<Exponent>"
                    + encodeBase64(removeMSZero(pukKey.getPublicExponent()
                            .toByteArray())) + "</Exponent>");
            buff.append("</RSAKeyValue>");
            return buff.toString();
        } catch (Exception e) {
            System.err.println(e);
            return null;
        }
    }

    /**
     * 公钥转换成C#格式
     * @param key
     * @return
     * @throws Exception
     */
    public static String encodePublicKeyToXml(PublicKey key) throws Exception {
        if (!RSAPublicKey.class.isInstance(key)) {
            return null;
        }
        RSAPublicKey pubKey = (RSAPublicKey) key;
        StringBuilder sb = new StringBuilder();

        sb.append("<RSAKeyValue>");
        sb.append("<Modulus>")
                .append(encodeBase64(removeMSZero(pubKey.getModulus()
                        .toByteArray()))).append("</Modulus>");
        sb.append("<Exponent>")
                .append(encodeBase64(removeMSZero(pubKey.getPublicExponent()
                        .toByteArray()))).append("</Exponent>");
        sb.append("</RSAKeyValue>");
        return sb.toString();
    }

    /**
     * @param data
     * @return
     */
    private static byte[] removeMSZero(byte[] data) {
        byte[] data1;
        int len = data.length;
        if (data[0] == 0) {
            data1 = new byte[data.length - 1];
            System.arraycopy(data, 1, data1, 0, len - 1);
        } else
            data1 = data;

        return data1;
    }

    /**
     * base64编码
     * @param input
     * @return
     * @throws Exception
     */
    public static String encodeBase64(byte[] input) throws Exception {
        Class clazz = Class
                .forName("com.sun.org.apache.xerces.internal.impl.dv.util.Base64");
        Method mainMethod = clazz.getMethod("encode", byte[].class);
        mainMethod.setAccessible(true);
        Object retObj = mainMethod.invoke(null, new Object[] { input });
        return (String) retObj;
    }

    /**
     * base64解码
     * @param input
     * @return
     * @throws Exception
     */
    public static byte[] decodeBase64(String input) throws Exception {
        Class clazz = Class
                .forName("com.sun.org.apache.xerces.internal.impl.dv.util.Base64");
        Method mainMethod = clazz.getMethod("decode", String.class);
        mainMethod.setAccessible(true);
        Object retObj = mainMethod.invoke(null, input);
        return (byte[]) retObj;
    }

    public static String byteToString(byte[] b)
            throws UnsupportedEncodingException {
        return new String(b, "utf-8");
    }
}

 

为了方便在服务器端使用，初始想法是想将java文件封装为.dll文件，共C#调用，测试后，发现这样做行不通，bug提示类找不到，这是因为java代码中还导入了其他jar包的缘故。

于是，退而求其次，将上述java文件Export为可执行的jar文件，并将生成的密钥对写入相应文件中。再由C#读取，提供给客户端。

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C# Java间进行RSA加密解密交互

C# Java间进行RSA加密解密交互（三）