RSA密钥之C#格式与Java格式转换

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一、转换原因

由于项目需求，服务端由Java编写，客户端由C#编写或者服务端由C#编写，客户端由Java编写。通信数据使用RSA非对称加密。但是java和c#生成的密钥格式是不一样的，所以需要转换格式才可以正常使用。

二、密钥格式

1.java密钥格式如下：

私钥：

[html] view plain copy

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

公钥：

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MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQCkmUkhHT4b++zuaHJyzRl3kNtaiQwKwtfsiHfvf6WOW15GZObwgePRKXzMDbpC7+gCaqH04WTzTrNbdNeX3RGCFJ5CHNkFcUcGtMU3hT+jfA+FkF0VrOHzRtuySuZD+ObPvSpSbceYbOxve2jHM3oSFqR2juo/Ypzpo5VPJetimQIDAQAB

2..NET密钥格式如下：

私钥：

[html] view plain copy

<RSAKeyValue>
<Modulus>pJlJIR0+G/vs7mhycs0Zd5DbWokMCsLX7Ih373+ljlteRmTm8IHj0Sl8zA26Qu/oAmqh9OFk806zW3TXl90RghSeQhzZBXFHBrTFN4U/o3wPhZBdFazh80bbskrmQ/jmz70qUm3HmGzsb3toxzN6Ehakdo7qP2Kc6aOVTyXrYpk=</Modulus>
<Exponent>AQAB</Exponent>
1WKkFg6jlS2eZSVLiH1CK4b9uhr7qE1/L+tPqKQs+PzHX4eiZXnyAlQ+kgGmL7n1wR1RWNuiYnDZUetmTogaDQ==
<Q>xXhsuEnNJNQcQHEVTPZoulbMbTV1VZIDQ1zjG8fvu8sv6IBYcR5+EsC8n3/6RkW8/iCJDzxE++VHzhoSQSoDvQ==</Q>
<DP>zr/rcn+umd0Aisnu/Ik48smxz39TdIfaAwkBPsoL1Re+6V2WyLG1/fG4SmmUpsuMRRdt+SWdmbnzpr7peo++hQ==</DP>
<DQ>MWi2W04sBEEGaKFi4QTuo2FAeTrdBvIn2t0M/lCCjYyDijtC5drpVKvhBk+xQZAFf9iIMsWzxQtTciBX3PI0SQ==</DQ>
<InverseQ>wGEfA3LWM4NHgRnXDqwwOUs3OtqWK0tsJPPcFMci+Bcgy96JpFTCr7bubXHMu14bdopCWUann2d3UuwEpvP+</InverseQ>
<D>mK3TRtMwRJb33OGnn9OeFumYfy92qxi3X6Hq1o6qDBW2qkd4bImfv+ni6AinyOVuaadt2Y+lq4dKGcCVJzoZvPm1VKxD2y7xKa8/vEbPRiRTt0qnPq9T7UJkpDsiXf/zOMfWdjc3uA1bPnQ65RWHSJ7zAE+Gd7xnyCE5MEyijLE=</D>
</RSAKeyValue>

公钥：

[html] view plain copy

<RSAKeyValue>
<Modulus>pJlJIR0+G/vs7mhycs0Zd5DbWokMCsLX7Ih373+ljlteRmTm8IHj0Sl8zA26Qu/oAmqh9OFk806zW3TXl90RghSeQhzZBXFHBrTFN4U/o3wPhZBdFazh80bbskrmQ/jmz70qUm3HmGzsb3toxzN6Ehakdo7qP2Kc6aOVTyXrYpk=</Modulus>
<Exponent>AQAB</Exponent>
</RSAKeyValue>

三、C#转换实现代码

参照：http://www.codes51.com/article/detail_106585.html
格式转换要用到一个开源加密库Bouncy Castle Crypto APIs，官网地址： http://www.bouncycastle.org/csharp/
具体实现代码如下：

[csharp] view plain copy

using System;
using System.Xml;
using Org.BouncyCastle.Asn1.Pkcs;
using Org.BouncyCastle.Asn1.X509;
using Org.BouncyCastle.Crypto.Parameters;
using Org.BouncyCastle.Math;
using Org.BouncyCastle.Pkcs;
using Org.BouncyCastle.Security;
using Org.BouncyCastle.X509;
/// <summary>
/// RSA密钥格式转换
/// </summary>
public class RSAKeyConvert
{
/// <summary>
/// RSA私钥格式转换，java->.net
/// </summary>
/// <param name="privateKey">java生成的RSA私钥</param>
/// <returns></returns>
public static string RSAPrivateKeyJava2DotNet(string privateKey)
{
RsaPrivateCrtKeyParameters privateKeyParam = (RsaPrivateCrtKeyParameters)PrivateKeyFactory.CreateKey(Convert.FromBase64String(privateKey));
return string.Format("<RSAKeyValue><Modulus>{0}</Modulus><Exponent>{1}</Exponent>{2}<Q>{3}</Q><DP>{4}</DP><DQ>{5}</DQ><InverseQ>{6}</InverseQ><D>{7}</D></RSAKeyValue>",
Convert.ToBase64String(privateKeyParam.Modulus.ToByteArrayUnsigned()),
Convert.ToBase64String(privateKeyParam.PublicExponent.ToByteArrayUnsigned()),
Convert.ToBase64String(privateKeyParam.P.ToByteArrayUnsigned()),
Convert.ToBase64String(privateKeyParam.Q.ToByteArrayUnsigned()),
Convert.ToBase64String(privateKeyParam.DP.ToByteArrayUnsigned()),
Convert.ToBase64String(privateKeyParam.DQ.ToByteArrayUnsigned()),
Convert.ToBase64String(privateKeyParam.QInv.ToByteArrayUnsigned()),
Convert.ToBase64String(privateKeyParam.Exponent.ToByteArrayUnsigned()));
}
/// <summary>
/// RSA私钥格式转换，.net->java
/// </summary>
/// <param name="privateKey">.net生成的私钥</param>
/// <returns></returns>
public static string RSAPrivateKeyDotNet2Java(string privateKey)
{
XmlDocument doc = new XmlDocument();
doc.LoadXml(privateKey);
BigInteger m = new BigInteger(1, Convert.FromBase64String(doc.DocumentElement.GetElementsByTagName("Modulus")[0].InnerText));
BigInteger exp = new BigInteger(1, Convert.FromBase64String(doc.DocumentElement.GetElementsByTagName("Exponent")[0].InnerText));
BigInteger d = new BigInteger(1, Convert.FromBase64String(doc.DocumentElement.GetElementsByTagName("D")[0].InnerText));
BigInteger p = new BigInteger(1, Convert.FromBase64String(doc.DocumentElement.GetElementsByTagName("P")[0].InnerText));
BigInteger q = new BigInteger(1, Convert.FromBase64String(doc.DocumentElement.GetElementsByTagName("Q")[0].InnerText));
BigInteger dp = new BigInteger(1, Convert.FromBase64String(doc.DocumentElement.GetElementsByTagName("DP")[0].InnerText));
BigInteger dq = new BigInteger(1, Convert.FromBase64String(doc.DocumentElement.GetElementsByTagName("DQ")[0].InnerText));
BigInteger qinv = new BigInteger(1, Convert.FromBase64String(doc.DocumentElement.GetElementsByTagName("InverseQ")[0].InnerText));
RsaPrivateCrtKeyParameters privateKeyParam = new RsaPrivateCrtKeyParameters(m, exp, d, p, q, dp, dq, qinv);
PrivateKeyInfo privateKeyInfo = PrivateKeyInfoFactory.CreatePrivateKeyInfo(privateKeyParam);
byte[] serializedPrivateBytes = privateKeyInfo.ToAsn1Object().GetEncoded();
return Convert.ToBase64String(serializedPrivateBytes);
}
/// <summary>
/// RSA公钥格式转换，java->.net
/// </summary>
/// <param name="publicKey">java生成的公钥</param>
/// <returns></returns>
public static string RSAPublicKeyJava2DotNet(string publicKey)
{
RsaKeyParameters publicKeyParam = (RsaKeyParameters)PublicKeyFactory.CreateKey(Convert.FromBase64String(publicKey));
return string.Format("<RSAKeyValue><Modulus>{0}</Modulus><Exponent>{1}</Exponent></RSAKeyValue>",
Convert.ToBase64String(publicKeyParam.Modulus.ToByteArrayUnsigned()),
Convert.ToBase64String(publicKeyParam.Exponent.ToByteArrayUnsigned()));
}
/// <summary>
/// RSA公钥格式转换，.net->java
/// </summary>
/// <param name="publicKey">.net生成的公钥</param>
/// <returns></returns>
public static string RSAPublicKeyDotNet2Java(string publicKey)
{
XmlDocument doc = new XmlDocument();
doc.LoadXml(publicKey);
BigInteger m = new BigInteger(1, Convert.FromBase64String(doc.DocumentElement.GetElementsByTagName("Modulus")[0].InnerText));
BigInteger p = new BigInteger(1, Convert.FromBase64String(doc.DocumentElement.GetElementsByTagName("Exponent")[0].InnerText));
RsaKeyParameters pub = new RsaKeyParameters(false, m, p);
SubjectPublicKeyInfo publicKeyInfo = SubjectPublicKeyInfoFactory.CreateSubjectPublicKeyInfo(pub);
byte[] serializedPublicBytes = publicKeyInfo.ToAsn1Object().GetDerEncoded();
return Convert.ToBase64String(serializedPublicBytes);
}
}

四、Java转换实现代码

就算不会JAVA的新手都可以转换的，只需要把以下的代码添加进eclipse中就可以了，具体的怎么建java工程就自己去查一下。
把一对密钥转成C#中格式的密钥在JAVA中的转换代码如下：

[java] view plain copy

package com;
import java.security.KeyFactory;
import java.security.PublicKey;
import java.security.interfaces.RSAPrivateCrtKey;
import java.security.interfaces.RSAPublicKey;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import com.sun.org.apache.xerces.internal.impl.dv.util.Base64;
public class test {
public static void main(String[] args) {
String tes = "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";
byte[] temp = b64decode(tes);
String ver = getRSAPrivateKeyAsNetFormat(temp);// 转换私钥
String tes1 = "MIGfMA0GCSqGSIb4DQEBAQUAA4GNADCBiQKBgQC/M9kJVwi+sO672NBm5fAEbUEl2PqRFuYZVB5ZrKah7eJPP0pKBe/eoA6pOMsjnKFoZGVizz7oCt+TJ+1fpuScn7vAtIFSjn1jgPANE+IcVdk4QKDFKu0LQdiurPQKLpq8Q3wJDAW7FxB2MHw/4ca/9w0N5VL0hQegZ4YhxDss6QIDAQAB";
byte[] temp1 = b64decode(tes1);
String ver1 = getRSAPublicKeyAsNetFormat(temp1);// 转换公钥
System.out.println(ver);
System.out.println(ver1);
}
private static String getRSAPrivateKeyAsNetFormat(byte[] encodedPrivkey) {
try {
StringBuffer buff = new StringBuffer(1024);
PKCS8EncodedKeySpec pvkKeySpec = new PKCS8EncodedKeySpec(
encodedPrivkey);
KeyFactory keyFactory = KeyFactory.getInstance("RSA");
RSAPrivateCrtKey pvkKey = (RSAPrivateCrtKey) keyFactory
.generatePrivate(pvkKeySpec);
buff.append("<RSAKeyValue>");
buff
.append("<Modulus>"
+ b64encode(removeMSZero(pvkKey.getModulus()
.toByteArray())) + "</Modulus>");
buff.append("<Exponent>"
+ b64encode(removeMSZero(pvkKey.getPublicExponent()
.toByteArray())) + "</Exponent>");
buff.append(""
+ b64encode(removeMSZero(pvkKey.getPrimeP().toByteArray()))
+ "");
buff.append("<Q>"
+ b64encode(removeMSZero(pvkKey.getPrimeQ().toByteArray()))
+ "</Q>");
buff.append("<DP>"
+ b64encode(removeMSZero(pvkKey.getPrimeExponentP()
.toByteArray())) + "</DP>");
buff.append("<DQ>"
+ b64encode(removeMSZero(pvkKey.getPrimeExponentQ()
.toByteArray())) + "</DQ>");
buff.append("<InverseQ>"
+ b64encode(removeMSZero(pvkKey.getCrtCoefficient()
.toByteArray())) + "</InverseQ>");
buff.append("<D>"
+ b64encode(removeMSZero(pvkKey.getPrivateExponent()
.toByteArray())) + "</D>");
buff.append("</RSAKeyValue>");
return buff.toString().replaceAll("[ \t\n\r]", "");
} catch (Exception e) {
System.err.println(e);
return null;
}
}
private static String getRSAPublicKeyAsNetFormat(byte[] encodedPrivkey) {
try {
StringBuffer buff = new StringBuffer(1024);
PKCS8EncodedKeySpec pvkKeySpec = new PKCS8EncodedKeySpec(
encodedPrivkey);
KeyFactory keyFactory = KeyFactory.getInstance("RSA");
RSAPublicKey pukKey = (RSAPublicKey) keyFactory
.generatePublic(new X509EncodedKeySpec(encodedPrivkey));
buff.append("<RSAKeyValue>");
buff
.append("<Modulus>"
+ b64encode(removeMSZero(pukKey.getModulus()
.toByteArray())) + "</Modulus>");
buff.append("<Exponent>"
+ b64encode(removeMSZero(pukKey.getPublicExponent()
.toByteArray())) + "</Exponent>");
buff.append("</RSAKeyValue>");
return buff.toString().replaceAll("[ \t\n\r]", "");
} catch (Exception e) {
System.err.println(e);
return null;
}
}
public static String encodePublicKeyToXml(PublicKey key) {
if (!RSAPublicKey.class.isInstance(key)) {
return null;
}
RSAPublicKey pubKey = (RSAPublicKey) key;
StringBuilder sb = new StringBuilder();
sb.append("<RSAKeyValue>");
sb.append("<Modulus>").append(
Base64.encode(pubKey.getModulus().toByteArray())).append(
"</Modulus>");
sb.append("<Exponent>").append(
Base64.encode(pubKey.getPublicExponent().toByteArray()))
.append("</Exponent>");
sb.append("</RSAKeyValue>");
return sb.toString();
}
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;
}
private static String b64encode(byte[] data) {
String b64str = new String(Base64.encode(data));
return b64str;
}
private static byte[] b64decode(String data) {
byte[] decodeData = Base64.decode(data);
return decodeData;
}
}