C#RSA算法实现+如何将公钥为XML格式转为PEM格式，给object-C使用
.net中，处于安全的考虑，RSACryptoServiceProvider类，解密时只有同时拥有公钥和私钥才可以。原因是公钥是公开的，会被多人持有。这样的数据传输是不安全的。C#RSA私钥加密，公钥解密出错的原因!
C#中用RSA算法生成公钥和私钥
方法一：
公钥密钥生成后，保存在同名文件夹下面，如下图：
公钥密钥生成，所在路径【RSA\RSA\bin\Debug】
using System;
using System.IO;
using System.Security.Cryptography;//必须引用
namespace RSA
{
class Program
{
static void Main(string[] args)
{
RSACryptoServiceProvider rsa = new RSACryptoServiceProvider();
using (StreamWriter writer = new StreamWriter("PrivateKey.xml")) //这个文件要保密...
{
writer.WriteLine(rsa.ToXmlString(true));
}
using (StreamWriter writer = new StreamWriter("PublicKey.xml"))
{
writer.WriteLine(rsa.ToXmlString(false));
}
}
}
}方法二：
public static void GKEY()//(计算机)生成密钥 GKEY(generate key),generate the RSA public and private keys
{
using (RSACryptoServiceProvider rsa = new RSACryptoServiceProvider())
{
string publicKey = rsa.ToXmlString(false); // 公钥
string privateKey = rsa.ToXmlString(true); // 私钥
}
}直接断点调式复制公钥密钥出来用
RSA加密解密类
#region RSA
/// <summary>
/// RSA加密
/// </summary>
/// <param name="publickey"></param>
/// <param name="content"></param>
/// <returns></returns>
public static string RSAEncrypt(string publickey, string content)
{
publickey = @"<RSAKeyValue><Modulus>0wE26IHp4U9OLtPhJ+fT8ej6aWORFP8pd++MjUuhkQQm/zhcImbxQbjxtSAftz+kkDwGDFJpSldQPyigOGcUx7PofTc6VhiFik9E9SsxV9n0iEEtqUndDfmBJfPAWt+4UDMwKakgZqFoapDuwjKlTErFvKCyKCs+qN9OZvZwKWk=</Modulus><Exponent>AQAB</Exponent></RSAKeyValue>";
RSACryptoServiceProvider rsa = new RSACryptoServiceProvider();
byte[] cipherbytes;
rsa.FromXmlString(publickey);
cipherbytes = rsa.Encrypt(Encoding.UTF8.GetBytes(content), false);
return Convert.ToBase64String(cipherbytes);
}
/// <summary>
/// RSA解密
/// </summary>
/// <param name="privatekey"></param>
/// <param name="content"></param>
/// <returns></returns>
public static string RSADecrypt(string privatekey, string content)
{
privatekey = @"<RSAKeyValue><Modulus>0wE26IHp4U9OLtPhJ+fT8ej6aWORFP8pd++MjUuhkQQm/zhcImbxQbjxtSAftz+kkDwGDFJpSldQPyigOGcUx7PofTc6VhiFik9E9SsxV9n0iEEtqUndDfmBJfPAWt+4UDMwKakgZqFoapDuwjKlTErFvKCyKCs+qN9OZvZwKWk=</Modulus><Exponent>AQAB</Exponent><P>8Ei6NIsZtgV3DQjuGHfGLS6o1O+IUXxzjqLxdMm77yhEPUxR9YPIxODJ2VVTddXSAHxViJJt30yJ7JhVz6cpQw==</P><Q>4M49NrmalgVQFMsea2RMB1qN8fAPfIw5G9q9hzsLcWSCmkeRRIQlvPYflVEKAYKiDVVzENETbnnduFXWBABx4w==</Q><DP>t+JQbemN0Zi5FQaif6MZzHYKynpNTl75aE0Wj5Pa+RlNr8N6bXNe8Bw/HM2Jw4HQ5oJASvYUk3DVlHS4JuP8VQ==</DP><DQ>lT62iv9brp9mU/epgVh71SH8PJPIZEJfo6tryjyb0zMMNcqvmZI1z6aCv0mm3+vPFBUXqCF1yhFj7n4l8FAvSw==</DQ><InverseQ>flrvgxHvf4l+fdymEVDgKjsfGqshOpppoNgZj9kpeWBto3o8z++Ki6eSLQT3nVnpx2QCZeTWkxTED4nhSLKscw==</InverseQ><D>cQTCg1Eqk7sltmFYxUYgOP/AOPjSufteG9acYwYymPkvZh6rAuY+rSRBmvGE62NUYskzuB/gM6iG2/2HrA5SixfNgCvZ+nsK+kX5pzQRsYdD71ViQW0hOanXwj45I2zHRgBiuTtCUP0fs5pISmQkaeJkDL5pO2l+wvlgl+wunj0=</D></RSAKeyValue>";
RSACryptoServiceProvider rsa = new RSACryptoServiceProvider();
byte[] cipherbytes;
rsa.FromXmlString(privatekey);
cipherbytes = rsa.Decrypt(Convert.FromBase64String(content), false);
return Encoding.UTF8.GetString(cipherbytes);
}
#endregion如何将公钥为XML格式转为PEM格式？
需要依赖一个第三方库，叫BouncyCastle
在线获取安装包的代码如下：
PM > Install-Package BouncyCastle
如果不知道怎么打开vs2013 控制台的请看下面
tips：打开VS2013控制台方法
打开VS2013控制台方法.png
安装第三方库成功图示.png
方法一：在线转换
如何将密钥XML格式和PEM格式互转？【tips：这里说的是密钥，公钥使用其他方法】
一、将XML格式密钥转PEM
public static void XMLConvertToPEM()//XML格式密钥转PEM
{
var rsa2 = new RSACryptoServiceProvider();
using (var sr = new StreamReader("e:\\PrivateKey.xml"))
{
rsa2.FromXmlString(sr.ReadToEnd());
}
var p = rsa2.ExportParameters(true);
var key = new RsaPrivateCrtKeyParameters(
new BigInteger(1, p.Modulus), new BigInteger(1, p.Exponent), new BigInteger(1, p.D),
new BigInteger(1, p.P), new BigInteger(1, p.Q), new BigInteger(1, p.DP), new BigInteger(1, p.DQ),
new BigInteger(1, p.InverseQ));
using (var sw = new StreamWriter("e:\\PrivateKey.pem"))
{
var pemWriter = new Org.BouncyCastle.OpenSsl.PemWriter(sw);
pemWriter.WriteObject(key);
}
}一、将PEM格式密钥转XML
public static void PEMConvertToXML()//PEM格式密钥转XML
{
AsymmetricCipherKeyPair keyPair;
using (var sr = new StreamReader("e:\\PrivateKey.pem"))
{
var pemReader = new Org.BouncyCastle.OpenSsl.PemReader(sr);
keyPair = (AsymmetricCipherKeyPair)pemReader.ReadObject();
}
var key = (RsaPrivateCrtKeyParameters)keyPair.Private;
var p = new RSAParameters
{
Modulus = key.Modulus.ToByteArrayUnsigned(),
Exponent = key.PublicExponent.ToByteArrayUnsigned(),
D = key.Exponent.ToByteArrayUnsigned(),
P = key.P.ToByteArrayUnsigned(),
Q = key.Q.ToByteArrayUnsigned(),
DP = key.DP.ToByteArrayUnsigned(),
DQ = key.DQ.ToByteArrayUnsigned(),
InverseQ = key.QInv.ToByteArrayUnsigned(),
};
var rsa = new RSACryptoServiceProvider();
rsa.ImportParameters(p);
using (var sw = new StreamWriter("e:\\PrivateKey.xml"))
{
sw.Write(rsa.ToXmlString(true));
}
}其他【tips：待测试】
CER和pfx证书.png
生成公钥.png
文／饭团小家（简书作者）
原文链接：http://www.jianshu.com/p/faefcc58c79b
著作权归作者所有，转载请联系作者获得授权，并标注“简书作者”。
原文链接：http://www.jianshu.com/p/faefcc58c79b
著作权归作者所有，转载请联系作者获得授权，并标注“简书作者”。
