这里,讲一下RSA算法加解密在C#和Java之间交互的问题,这两天纠结了很久,也看了很多其他人写的文章,颇受裨益,但没能解决我的实际问题,终于,还是被我捣鼓出来了。
首先,介绍一下写这代码的目的:完成webService验证问题,服务器端采用C#开发,客户端采用Java开发。服务器端给客户端提供公钥,已进行数据加密,客户端加密后提数据提交给服务器,服务器用私钥对数据解密,进行验证。
这里遇到的主要问题是C# RSACryptoServiceProvider类产生的公钥、私钥都是xml字符串数据,而java RSA算法要求的 Modulus、Exponent都是BigInteger类型,两者间的转换才是问题所在。
关于Java 和 C#各自独立的进行RSA加密解密,大家可以看整两篇文章,java RSA加密解密实现() 和 C#中RSA加密解密和签名与验证的实现。
接下来讲一下实现步骤:
首先由C# RSACryptoServiceProvider类生成公钥、私钥
- /// <summary>
- /// 生成公钥、私钥
- /// </summary>
- /// <returns>公钥、私钥,公钥键"PUBLIC",私钥键"PRIVATE"</returns>
- public Dictionary<string, string> createKeyPair()
- {
- Dictionary<string, string> keyPair = new Dictionary<string, string>();
- RSACryptoServiceProvider provider = new RSACryptoServiceProvider(1024);
- keyPair.Add("PUBLIC", provider.ToXmlString(false));
- keyPair.Add("PRIVATE", provider.ToXmlString(true));
- return keyPair;
- }
- /// <summary>
- /// 生成公钥、私钥
- /// </summary>
- /// <returns>公钥、私钥,公钥键"PUBLIC",私钥键"PRIVATE"</returns>
- public Dictionary<string, string> createKeyPair()
- {
- Dictionary<string, string> keyPair = new Dictionary<string, string>();
- RSACryptoServiceProvider provider = new RSACryptoServiceProvider(1024);
- keyPair.Add("PUBLIC", provider.ToXmlString(false));
- keyPair.Add("PRIVATE", provider.ToXmlString(true));
- return keyPair;
- }
如此处生成的公钥为
- <RSAKeyValue>
- <Modulus>t+56m5jXXonAJAKC7mgkhAZX5gWJTZojbSloLpLBGEWiebFaM+aUUKALfRx83/HaUV79ZiR3zuLJOLBdALx1cmcPk/b9fdNblLmzqi4cfSnfmMLWh05xf+ZS1pKHSKQtui3dfuu+3XH6Ak+S38dpIZUj/hihQQuKysN6GJ9h+c8=
- </Modulus>
- <Exponent>AQAB</Exponent>
- </RSAKeyValue>
- <RSAKeyValue>
- <Modulus>t+56m5jXXonAJAKC7mgkhAZX5gWJTZojbSloLpLBGEWiebFaM+aUUKALfRx83/HaUV79ZiR3zuLJOLBdALx1cmcPk/b9fdNblLmzqi4cfSnfmMLWh05xf+ZS1pKHSKQtui3dfuu+3XH6Ak+S38dpIZUj/hihQQuKysN6GJ9h+c8=
- </Modulus>
- <Exponent>AQAB</Exponent>
- </RSAKeyValue>
- /**
- * 返回包含模数modulus和指数exponent的haspMap
- * @return
- * @throws MalformedURLException
- * @throws DocumentException
- */
- public static HashMap<String,String> rsaParameters(String xmlPublicKey) throws MalformedURLException, DocumentException{
- HashMap<String ,String> map = new HashMap<String, String>();
- Document doc = DocumentHelper.parseText(xmlPublicKey);
- String mudulus = (String) doc.getRootElement().element("Modulus").getData();
- String exponent = (String) doc.getRootElement().element("Exponent").getData();
- map.put("mudulus", mudulus);
- map.put("exponent", exponent);
- return map;
- }
- /**
- * 返回包含模数modulus和指数exponent的haspMap
- * @return
- * @throws MalformedURLException
- * @throws DocumentException
- */
- public static HashMap<String,String> rsaParameters(String xmlPublicKey) throws MalformedURLException, DocumentException{
- HashMap<String ,String> map = new HashMap<String, String>();
- Document doc = DocumentHelper.parseText(xmlPublicKey);
- String mudulus = (String) doc.getRootElement().element("Modulus").getData();
- String exponent = (String) doc.getRootElement().element("Exponent").getData();
- map.put("mudulus", mudulus);
- map.put("exponent", exponent);
- return map;
- }
用Modulus和Exponent产生公钥RSAPublicKey(java)
这里有个关键步骤先对Mudolus和Exponent进行Base64解码,这个是由于C#生成的密钥对,其参数已经过Base64编码成String类型,而java RSA参数是未经base64编码的byte[]类型。
至于Base64编码、解码方法,参考这篇文章,java 编码和解码,想详细。
- 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;
- }
- /**
- * 返回RSA公钥
- * @param modules
- * @param exponent
- * @return
- */
- public static PublicKey getPublicKey(String modulus, String exponent){
- try {
- byte[] m = decodeBase64(modulus);
- byte[] e = decodeBase64(exponent);
- BigInteger b1 = new BigInteger(1,m);
- BigInteger b2 = new BigInteger(1,e);
- KeyFactory keyFactory = KeyFactory.getInstance("RSA");
- RSAPublicKeySpec keySpec = new RSAPublicKeySpec(b1, b2);
- return (RSAPublicKey) keyFactory.generatePublic(keySpec);
- } catch (Exception e) {
- e.printStackTrace();
- return null;
- }
- }
- 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;
- }
- /**
- * 返回RSA公钥
- * @param modules
- * @param exponent
- * @return
- */
- public static PublicKey getPublicKey(String modulus, String exponent){
- try {
- byte[] m = decodeBase64(modulus);
- byte[] e = decodeBase64(exponent);
- BigInteger b1 = new BigInteger(1,m);
- BigInteger b2 = new BigInteger(1,e);
- KeyFactory keyFactory = KeyFactory.getInstance("RSA");
- RSAPublicKeySpec keySpec = new RSAPublicKeySpec(b1, b2);
- return (RSAPublicKey) keyFactory.generatePublic(keySpec);
- } catch (Exception e) {
- e.printStackTrace();
- return null;
- }
- }
获得公钥后就可以进行RSA加密处理了,这里还有一点需要提的是,RSA加密解密都有最大长度限制,加密最大长度为117字节,解密最大长度是128字节,此外,此处加密得到的数据是经过Base64编码处理的
- public static String encrypt(byte[] source, PublicKey publicKey) throws Exception {
- String encryptData ="";
- try {
- Cipher cipher = Cipher.getInstance("RSA");
- cipher.init(Cipher.ENCRYPT_MODE, publicKey);
- int length = source.length;
- int offset = 0;
- byte[] cache;
- ByteArrayOutputStream outStream = new ByteArrayOutputStream();
- int i = 0;
- while(length - offset > 0){
- if(length - offset > MAXENCRYPTSIZE){
- cache = cipher.doFinal(source, offset, MAXENCRYPTSIZE);
- }else{
- cache = cipher.doFinal(source, offset, length - offset);
- }
- outStream.write(cache, 0, cache.length);
- i++;
- offset = i * MAXENCRYPTSIZE;
- }
- return encodeBase64(outStream.toByteArray());
- } catch (NoSuchAlgorithmException e) {
- e.printStackTrace();
- } catch (NoSuchPaddingException e) {
- e.printStackTrace();
- } catch (InvalidKeyException e) {
- e.printStackTrace();
- } catch (IllegalBlockSizeException e) {
- e.printStackTrace();
- } catch (BadPaddingException e) {
- e.printStackTrace();
- }
- return encryptData;
- }
- public static String encrypt(byte[] source, PublicKey publicKey) throws Exception {
- String encryptData ="";
- try {
- Cipher cipher = Cipher.getInstance("RSA");
- cipher.init(Cipher.ENCRYPT_MODE, publicKey);
- int length = source.length;
- int offset = 0;
- byte[] cache;
- ByteArrayOutputStream outStream = new ByteArrayOutputStream();
- int i = 0;
- while(length - offset > 0){
- if(length - offset > MAXENCRYPTSIZE){
- cache = cipher.doFinal(source, offset, MAXENCRYPTSIZE);
- }else{
- cache = cipher.doFinal(source, offset, length - offset);
- }
- outStream.write(cache, 0, cache.length);
- i++;
- offset = i * MAXENCRYPTSIZE;
- }
- return encodeBase64(outStream.toByteArray());
- } catch (NoSuchAlgorithmException e) {
- e.printStackTrace();
- } catch (NoSuchPaddingException e) {
- e.printStackTrace();
- } catch (InvalidKeyException e) {
- e.printStackTrace();
- } catch (IllegalBlockSizeException e) {
- e.printStackTrace();
- } catch (BadPaddingException e) {
- e.printStackTrace();
- }
- return encryptData;
- }
加密后的数据提交给C#服务器端进行解密,当然,这里也要注意最大长度限制问题
- /// <summary>
- /// RSA解密
- /// </summary>
- /// <param name="encryptData">经过Base64编码的密文</param>
- /// <param name="privateKey">私钥</param>
- /// <returns>RSA解密后的数据</returns>
- public static string decrypt(string encryptData, string privateKey)
- {
- string decryptData = "";
- try
- {
- RSACryptoServiceProvider provider = new RSACryptoServiceProvider();
- provider.FromXmlString(privateKey);
- byte[] bEncrypt = Convert.FromBase64String(encryptData);
- int length = bEncrypt.Length;
- int offset = 0;
- string cache ;
- int i = 0;
- while (length - offset > 0)
- {
- if (length - offset > MAXDECRYPTSIZE)
- {
- cache = Encoding.UTF8.GetString(provider.Decrypt(getSplit(bEncrypt, offset, MAXDECRYPTSIZE), false));
- }
- else
- {
- cache = Encoding.UTF8.GetString(provider.Decrypt(getSplit(bEncrypt, offset, length - offset), false));
- }
- decryptData += cache;
- i++;
- offset = i*MAXDECRYPTSIZE;
- }
- }
- catch(Exception e)
- {
- throw e;
- }
- return decryptData;
- }
- /// <summary>
- /// 截取字节数组部分字节
- /// </summary>
- /// <param name="input"></param>
- /// <param name="offset">起始偏移位</param>
- /// <param name="length">截取长度</param>
- /// <returns></returns>
- private static byte[] getSplit(byte[] input, int offset, int length)
- {
- byte[] output = new byte[length];
- for (int i = offset; i < offset + length; i++)
- {
- output[i - offset] = input[i];
- }
- return output;
- }
- /// <summary>
- /// RSA解密
- /// </summary>
- /// <param name="encryptData">经过Base64编码的密文</param>
- /// <param name="privateKey">私钥</param>
- /// <returns>RSA解密后的数据</returns>
- public static string decrypt(string encryptData, string privateKey)
- {
- string decryptData = "";
- try
- {
- RSACryptoServiceProvider provider = new RSACryptoServiceProvider();
- provider.FromXmlString(privateKey);
- byte[] bEncrypt = Convert.FromBase64String(encryptData);
- int length = bEncrypt.Length;
- int offset = 0;
- string cache ;
- int i = 0;
- while (length - offset > 0)
- {
- if (length - offset > MAXDECRYPTSIZE)
- {
- cache = Encoding.UTF8.GetString(provider.Decrypt(getSplit(bEncrypt, offset, MAXDECRYPTSIZE), false));
- }
- else
- {
- cache = Encoding.UTF8.GetString(provider.Decrypt(getSplit(bEncrypt, offset, length - offset), false));
- }
- decryptData += cache;
- i++;
- offset = i*MAXDECRYPTSIZE;
- }
- }
- catch(Exception e)
- {
- throw e;
- }
- return decryptData;
- }
- /// <summary>
- /// 截取字节数组部分字节
- /// </summary>
- /// <param name="input"></param>
- /// <param name="offset">起始偏移位</param>
- /// <param name="length">截取长度</param>
- /// <returns></returns>
- private static byte[] getSplit(byte[] input, int offset, int length)
- {
- byte[] output = new byte[length];
- for (int i = offset; i < offset + length; i++)
- {
- output[i - offset] = input[i];
- }
- return output;
- }
经过测试,这样做的确得到了正确的结果。
若是有什么地方有问题,还望大家指正!
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C# Java间进行RSA加密解密交互(二)
C# Java间进行RSA加密解密交互(三)
转自:http://blog.csdn.net/dslinmy/article/details/37362661