cer, pfx 创建，并且读取公钥/密钥，加解密 （C#程序实现）

PKI技术（public key infrastructure）里面，cer文件和pfx文件是很常见的。通常cer文件里面保存着公钥以及用户的一些信息，pfx里面则含有私钥和公钥。

用makecert.exe可以创建公钥证书和私钥证书，具体看

http://msdn.microsoft.com/zh-cn/library/bfsktky3(v=vs.110).aspx

http://blog.csdn.net/hacode/article/details/4240238

 

这里使用程序的方法来创建。参考了http://www.cnblogs.com/luminji/archive/2010/10/28/1863179.html

下面的代码封装了一个类，可以在store里面创建一个认证，并且导出到cer，pfx，然后从store，cer，pfx读取信息

public sealed class DataCertificate   
    {  
        #region 生成证书   
        /// <summary>   
        /// 根据指定的证书名和makecert全路径生成证书（包含公钥和私钥，并保存在MY存储区）   
        /// </summary>   
        /// <param name="subjectName"></param>   
        /// <param name="makecertPath"></param>   
        /// <returns></returns>   
        public static bool CreateCertWithPrivateKey(string subjectName, string makecertPath)   
        {   
            subjectName = "CN=" + subjectName;   
            string param = " -pe -ss my -n \"" + subjectName + "\" ";   
            try  
            {   
                Process p = Process.Start(makecertPath, param);   
                p.WaitForExit();   
                p.Close();   
            }   
            catch (Exception e)   
            {   
                return false;   
            }   
            return true;   
        }  
        #endregion  
 
        #region 文件导入导出   
        /// <summary>   
        /// 从WINDOWS证书存储区的个人MY区找到主题为subjectName的证书，   
        /// 并导出为pfx文件，同时为其指定一个密码   
        /// 并将证书从个人区删除(如果isDelFromstor为true)   
        /// </summary>   
        /// <param name="subjectName">证书主题，不包含CN=</param>   
        /// <param name="pfxFileName">pfx文件名</param>   
        /// <param name="password">pfx文件密码</param>   
        /// <param name="isDelFromStore">是否从存储区删除</param>   
        /// <returns></returns>   
        public static bool ExportToPfxFile(string subjectName, string pfxFileName,   
            string password, bool isDelFromStore)   
        {   
            subjectName = "CN=" + subjectName;   
            X509Store store = new X509Store(StoreName.My, StoreLocation.CurrentUser);   
            store.Open(OpenFlags.ReadWrite);   
            X509Certificate2Collection storecollection = (X509Certificate2Collection)store.Certificates;   
            foreach (X509Certificate2 x509 in storecollection)   
            {   
                if (x509.Subject == subjectName)   
                {   
                    Debug.Print(string.Format("certificate name: {0}", x509.Subject));   
  
                    byte[] pfxByte = x509.Export(X509ContentType.Pfx, password);   
                    using (FileStream fileStream = new FileStream(pfxFileName, FileMode.Create))   
                    {   
                        // Write the data to the file, byte by byte.   
                        for (int i = 0; i < pfxByte.Length; i++)   
                            fileStream.WriteByte(pfxByte[i]);   
                        // Set the stream position to the beginning of the file.   
                        fileStream.Seek(0, SeekOrigin.Begin);   
                        // Read and verify the data.   
                        for (int i = 0; i < fileStream.Length; i++)   
                        {   
                            if (pfxByte[i] != fileStream.ReadByte())   
                            {   
                                fileStream.Close();   
                                return false;   
                            }   
                        }   
                        fileStream.Close();   
                    }   
                    if( isDelFromStore == true)   
                        store.Remove(x509);   
                }   
            }   
            store.Close();   
            store = null;   
            storecollection = null;   
            return true;   
        }   
        /// <summary>   
        /// 从WINDOWS证书存储区的个人MY区找到主题为subjectName的证书，   
        /// 并导出为CER文件（即，只含公钥的）   
        /// </summary>   
        /// <param name="subjectName"></param>   
        /// <param name="cerFileName"></param>   
        /// <returns></returns>   
        public static bool ExportToCerFile(string subjectName, string cerFileName)   
        {   
            subjectName = "CN=" + subjectName;   
            X509Store store = new X509Store(StoreName.My, StoreLocation.CurrentUser);   
            store.Open(OpenFlags.ReadWrite);   
            X509Certificate2Collection storecollection = (X509Certificate2Collection)store.Certificates;   
            foreach (X509Certificate2 x509 in storecollection)   
            {   
                if (x509.Subject == subjectName)   
                {   
                    Debug.Print(string.Format("certificate name: {0}", x509.Subject));   
                    //byte[] pfxByte = x509.Export(X509ContentType.Pfx, password);   
                    byte[] cerByte = x509.Export(X509ContentType.Cert);   
                    using (FileStream fileStream = new FileStream(cerFileName, FileMode.Create))   
                    {   
                        // Write the data to the file, byte by byte.   
                        for (int i = 0; i < cerByte.Length; i++)   
                            fileStream.WriteByte(cerByte[i]);   
                        // Set the stream position to the beginning of the file.   
                        fileStream.Seek(0, SeekOrigin.Begin);   
                        // Read and verify the data.   
                        for (int i = 0; i < fileStream.Length; i++)   
                        {   
                            if (cerByte[i] != fileStream.ReadByte())   
                            {   
                                fileStream.Close();   
                                return false;   
                            }   
                        }   
                        fileStream.Close();   
                    }   
                }   
            }   
            store.Close();   
            store = null;   
            storecollection = null;   
            return true;   
        }  
        #endregion  
 
        #region 从证书中获取信息   
        /// <summary>   
        /// 根据私钥证书得到证书实体，得到实体后可以根据其公钥和私钥进行加解密   
        /// 加解密函数使用DEncrypt的RSACryption类   
        /// </summary>   
        /// <param name="pfxFileName"></param>   
        /// <param name="password"></param>   
        /// <returns></returns>   
        public static X509Certificate2 GetCertificateFromPfxFile(string pfxFileName,   
            string password)   
        {   
            try  
            {   
                return new X509Certificate2(pfxFileName, password, X509KeyStorageFlags.Exportable);   
            }   
            catch (Exception e)   
            {   
                return null;   
            }   
        }   
        /// <summary>   
        /// 到存储区获取证书   
        /// </summary>   
        /// <param name="subjectName"></param>   
        /// <returns></returns>   
        public static X509Certificate2 GetCertificateFromStore(string subjectName)   
        {   
            subjectName = "CN=" + subjectName;   
            X509Store store = new X509Store(StoreName.My, StoreLocation.CurrentUser);   
            store.Open(OpenFlags.ReadWrite);   
            X509Certificate2Collection storecollection = (X509Certificate2Collection)store.Certificates;   
            foreach (X509Certificate2 x509 in storecollection)   
            {   
                if (x509.Subject == subjectName)   
                {   
                    return x509;   
                }   
            }   
            store.Close();   
            store = null;   
            storecollection = null;   
            return null;   
        }   
       /// <summary>   
        /// 根据公钥证书，返回证书实体   
        /// </summary>   
        /// <param name="cerPath"></param>   
        public static X509Certificate2 GetCertFromCerFile(string cerPath)   
        {   
            try  
            {   
                return new X509Certificate2(cerPath);   
            }   
            catch (Exception e)   
            {    
                return null;   
            }               
        }  
        #endregion          
    }  

两个RSA加解密辅助函数：

        static string RSADecrypt(string xmlPrivateKey, string m_strDecryptString)   
        {   
            RSACryptoServiceProvider provider = new RSACryptoServiceProvider();   
            provider.FromXmlString(xmlPrivateKey);   
            byte[] rgb = Convert.FromBase64String(m_strDecryptString);   
            byte[] bytes = provider.Decrypt(rgb, false);   
            return new UnicodeEncoding().GetString(bytes);   
        }   
        /// <summary>   
        /// RSA加密   
        /// </summary>   
        /// <param name="xmlPublicKey"></param>   
        /// <param name="m_strEncryptString"></param>   
        /// <returns></returns>   
        static string RSAEncrypt(string xmlPublicKey, string m_strEncryptString)   
        {   
            RSACryptoServiceProvider provider = new RSACryptoServiceProvider();   
            provider.FromXmlString(xmlPublicKey);   
            byte[] bytes = new UnicodeEncoding().GetBytes(m_strEncryptString);   
            return Convert.ToBase64String(provider.Encrypt(bytes, false));   
        }  

使用例子，下面的代码做了几个事情

1. 在个人store里面创建了一个认证， 从认证里面读取信息得到一个X509Certificate2的对象，这个对象内部包含公钥和私钥，然后做了次rsa加解密测试。

2. 从store里面导出一个cer文件，因为cer文件并没有私钥，只有公钥。测试代码就是用公钥加密然后用前面得到的私钥解密。

3. 导出一个pfx文件，pfx包括公钥和私钥，可以自己加解密。

这是个很简单的例子，但是对于理解cer文件和pfx文件已经公钥私钥应该有帮助。

            // 在personal（个人）里面创建一个foo的证书
            DataCertificate.CreateCertWithPrivateKey("foo", "C:\\Program Files (x86)\\Windows Kits\\8.1\\bin\\x64\\makecert.exe");

            // 获取证书
            X509Certificate2 c1 = DataCertificate.GetCertificateFromStore("foo");

            string keyPublic = c1.PublicKey.Key.ToXmlString(false);  // 公钥
            string keyPrivate = c1.PrivateKey.ToXmlString(true);  // 私钥

            string cypher = RSAEncrypt(keyPublic, "程序员");  // 加密
            string plain = RSADecrypt(keyPrivate, cypher);  // 解密

            Debug.Assert(plain == "程序员");

            // 生成一个cert文件
            DataCertificate.ExportToCerFile("foo", "d:\\mycert\\foo.cer");

            X509Certificate2 c2 = DataCertificate.GetCertFromCerFile("d:\\mycert\\foo.cer");

            string keyPublic2 = c2.PublicKey.Key.ToXmlString(false);

            bool b = keyPublic2 == keyPublic;
            string cypher2 = RSAEncrypt(keyPublic2, "程序员2");  // 加密
            string plain2 = RSADecrypt(keyPrivate, cypher2);  // 解密, cer里面并没有私钥，所以这里使用前面得到的私钥来解密

            Debug.Assert(plain2 == "程序员2");

            // 生成一个pfx， 并且从store里面删除
            DataCertificate.ExportToPfxFile("foo", "d:\\mycert\\foo.pfx", "111", true);

            X509Certificate2 c3 = DataCertificate.GetCertificateFromPfxFile("d:\\mycert\\foo.pfx", "111");

            string keyPublic3 = c3.PublicKey.Key.ToXmlString(false);  // 公钥
            string keyPrivate3 = c3.PrivateKey.ToXmlString(true);  // 私钥

            string cypher3 = RSAEncrypt(keyPublic3, "程序员3");  // 加密
            string plain3 = RSADecrypt(keyPrivate3, cypher3);  // 解密

            Debug.Assert(plain3 == "程序员3");

附：完整代码

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.IO;
using System.Linq;
using System.Security.Cryptography;
using System.Security.Cryptography.X509Certificates;
using System.Text;


namespace ConsoleApplication1
{
    public sealed class DataCertificate   
    {  
        #region 生成证书   
        /// <summary>   
        /// 根据指定的证书名和makecert全路径生成证书（包含公钥和私钥，并保存在MY存储区）   
        /// </summary>   
        /// <param name="subjectName"></param>   
        /// <param name="makecertPath"></param>   
        /// <returns></returns>   
        public static bool CreateCertWithPrivateKey(string subjectName, string makecertPath)   
        {   
            subjectName = "CN=" + subjectName;   
            string param = " -pe -ss my -n \"" + subjectName + "\" ";   
            try  
            {   
                Process p = Process.Start(makecertPath, param);   
                p.WaitForExit();   
                p.Close();   
            }   
            catch (Exception e)   
            {   
                return false;   
            }   
            return true;   
        }  
        #endregion  
 
        #region 文件导入导出   
        /// <summary>   
        /// 从WINDOWS证书存储区的个人MY区找到主题为subjectName的证书，   
        /// 并导出为pfx文件，同时为其指定一个密码   
        /// 并将证书从个人区删除(如果isDelFromstor为true)   
        /// </summary>   
        /// <param name="subjectName">证书主题，不包含CN=</param>   
        /// <param name="pfxFileName">pfx文件名</param>   
        /// <param name="password">pfx文件密码</param>   
        /// <param name="isDelFromStore">是否从存储区删除</param>   
        /// <returns></returns>   
        public static bool ExportToPfxFile(string subjectName, string pfxFileName,   
            string password, bool isDelFromStore)   
        {   
            subjectName = "CN=" + subjectName;   
            X509Store store = new X509Store(StoreName.My, StoreLocation.CurrentUser);   
            store.Open(OpenFlags.ReadWrite);   
            X509Certificate2Collection storecollection = (X509Certificate2Collection)store.Certificates;   
            foreach (X509Certificate2 x509 in storecollection)   
            {   
                if (x509.Subject == subjectName)   
                {   
                    Debug.Print(string.Format("certificate name: {0}", x509.Subject));   
  
                    byte[] pfxByte = x509.Export(X509ContentType.Pfx, password);   
                    using (FileStream fileStream = new FileStream(pfxFileName, FileMode.Create))   
                    {   
                        // Write the data to the file, byte by byte.   
                        for (int i = 0; i < pfxByte.Length; i++)   
                            fileStream.WriteByte(pfxByte[i]);   
                        // Set the stream position to the beginning of the file.   
                        fileStream.Seek(0, SeekOrigin.Begin);   
                        // Read and verify the data.   
                        for (int i = 0; i < fileStream.Length; i++)   
                        {   
                            if (pfxByte[i] != fileStream.ReadByte())   
                            {   
                                fileStream.Close();   
                                return false;   
                            }   
                        }   
                        fileStream.Close();   
                    }   
                    if( isDelFromStore == true)   
                        store.Remove(x509);   
                }   
            }   
            store.Close();   
            store = null;   
            storecollection = null;   
            return true;   
        }   
        /// <summary>   
        /// 从WINDOWS证书存储区的个人MY区找到主题为subjectName的证书，   
        /// 并导出为CER文件（即，只含公钥的）   
        /// </summary>   
        /// <param name="subjectName"></param>   
        /// <param name="cerFileName"></param>   
        /// <returns></returns>   
        public static bool ExportToCerFile(string subjectName, string cerFileName)   
        {   
            subjectName = "CN=" + subjectName;   
            X509Store store = new X509Store(StoreName.My, StoreLocation.CurrentUser);   
            store.Open(OpenFlags.ReadWrite);   
            X509Certificate2Collection storecollection = (X509Certificate2Collection)store.Certificates;   
            foreach (X509Certificate2 x509 in storecollection)   
            {   
                if (x509.Subject == subjectName)   
                {   
                    Debug.Print(string.Format("certificate name: {0}", x509.Subject));   
                    //byte[] pfxByte = x509.Export(X509ContentType.Pfx, password);   
                    byte[] cerByte = x509.Export(X509ContentType.Cert);   
                    using (FileStream fileStream = new FileStream(cerFileName, FileMode.Create))   
                    {   
                        // Write the data to the file, byte by byte.   
                        for (int i = 0; i < cerByte.Length; i++)   
                            fileStream.WriteByte(cerByte[i]);   
                        // Set the stream position to the beginning of the file.   
                        fileStream.Seek(0, SeekOrigin.Begin);   
                        // Read and verify the data.   
                        for (int i = 0; i < fileStream.Length; i++)   
                        {   
                            if (cerByte[i] != fileStream.ReadByte())   
                            {   
                                fileStream.Close();   
                                return false;   
                            }   
                        }   
                        fileStream.Close();   
                    }   
                }   
            }   
            store.Close();   
            store = null;   
            storecollection = null;   
            return true;   
        }  
        #endregion  
 
        #region 从证书中获取信息   
        /// <summary>   
        /// 根据私钥证书得到证书实体，得到实体后可以根据其公钥和私钥进行加解密   
        /// 加解密函数使用DEncrypt的RSACryption类   
        /// </summary>   
        /// <param name="pfxFileName"></param>   
        /// <param name="password"></param>   
        /// <returns></returns>   
        public static X509Certificate2 GetCertificateFromPfxFile(string pfxFileName,   
            string password)   
        {   
            try  
            {   
                return new X509Certificate2(pfxFileName, password, X509KeyStorageFlags.Exportable);   
            }   
            catch (Exception e)   
            {   
                return null;   
            }   
        }   
        /// <summary>   
        /// 到存储区获取证书   
        /// </summary>   
        /// <param name="subjectName"></param>   
        /// <returns></returns>   
        public static X509Certificate2 GetCertificateFromStore(string subjectName)   
        {   
            subjectName = "CN=" + subjectName;   
            X509Store store = new X509Store(StoreName.My, StoreLocation.CurrentUser);   
            store.Open(OpenFlags.ReadWrite);   
            X509Certificate2Collection storecollection = (X509Certificate2Collection)store.Certificates;   
            foreach (X509Certificate2 x509 in storecollection)   
            {   
                if (x509.Subject == subjectName)   
                {   
                    return x509;   
                }   
            }   
            store.Close();   
            store = null;   
            storecollection = null;   
            return null;   
        }   
       /// <summary>   
        /// 根据公钥证书，返回证书实体   
        /// </summary>   
        /// <param name="cerPath"></param>   
        public static X509Certificate2 GetCertFromCerFile(string cerPath)   
        {   
            try  
            {   
                return new X509Certificate2(cerPath);   
            }   
            catch (Exception e)   
            {    
                return null;   
            }               
        }  
        #endregion          
    }  

    class Program
    {
        static string RSADecrypt(string xmlPrivateKey, string m_strDecryptString)   
        {   
            RSACryptoServiceProvider provider = new RSACryptoServiceProvider();   
            provider.FromXmlString(xmlPrivateKey);   
            byte[] rgb = Convert.FromBase64String(m_strDecryptString);   
            byte[] bytes = provider.Decrypt(rgb, false);   
            return new UnicodeEncoding().GetString(bytes);   
        }   
        /// <summary>   
        /// RSA加密   
        /// </summary>   
        /// <param name="xmlPublicKey"></param>   
        /// <param name="m_strEncryptString"></param>   
        /// <returns></returns>   
        static string RSAEncrypt(string xmlPublicKey, string m_strEncryptString)   
        {   
            RSACryptoServiceProvider provider = new RSACryptoServiceProvider();   
            provider.FromXmlString(xmlPublicKey);   
            byte[] bytes = new UnicodeEncoding().GetBytes(m_strEncryptString);   
            return Convert.ToBase64String(provider.Encrypt(bytes, false));   
        }  

        static void Main(string[] args)
        {
            // 在personal（个人）里面创建一个foo的证书
            DataCertificate.CreateCertWithPrivateKey("foo", "C:\\Program Files (x86)\\Windows Kits\\8.1\\bin\\x64\\makecert.exe");

            // 获取证书
            X509Certificate2 c1 = DataCertificate.GetCertificateFromStore("foo");

            string keyPublic = c1.PublicKey.Key.ToXmlString(false);  // 公钥
            string keyPrivate = c1.PrivateKey.ToXmlString(true);  // 私钥

            string cypher = RSAEncrypt(keyPublic, "程序员");  // 加密
            string plain = RSADecrypt(keyPrivate, cypher);  // 解密

            Debug.Assert(plain == "程序员");

            // 生成一个cert文件
            DataCertificate.ExportToCerFile("foo", "d:\\mycert\\foo.cer");

            X509Certificate2 c2 = DataCertificate.GetCertFromCerFile("d:\\mycert\\foo.cer");

            string keyPublic2 = c2.PublicKey.Key.ToXmlString(false);

            bool b = keyPublic2 == keyPublic;
            string cypher2 = RSAEncrypt(keyPublic2, "程序员2");  // 加密
            string plain2 = RSADecrypt(keyPrivate, cypher2);  // 解密, cer里面并没有私钥，所以这里使用前面得到的私钥来解密

            Debug.Assert(plain2 == "程序员2");

            // 生成一个pfx， 并且从store里面删除
            DataCertificate.ExportToPfxFile("foo", "d:\\mycert\\foo.pfx", "111", true);

            X509Certificate2 c3 = DataCertificate.GetCertificateFromPfxFile("d:\\mycert\\foo.pfx", "111");

            string keyPublic3 = c3.PublicKey.Key.ToXmlString(false);  // 公钥
            string keyPrivate3 = c3.PrivateKey.ToXmlString(true);  // 私钥

            string cypher3 = RSAEncrypt(keyPublic3, "程序员3");  // 加密
            string plain3 = RSADecrypt(keyPrivate3, cypher3);  // 解密

            Debug.Assert(plain3 == "程序员3");
        }
    }
}