BouncyCastle产生一个PKCS#12规范的PFX/p12证书

RT，在C#中实现，依赖.netFramework2.0

BouncyCastle中提供了PKCS12Store，Pkcs12StoreBuilder，AsymmetricKeyEntry，X509CertificateEntry等接口

其中Pkcs12StoreBuilder建立一个PKCS12Store对象，PKCS12Store对象来产生一个pfx/p12格式的证书，该证书符合PKCS#12规范

PKCS#12的ref，见RSA给出的文档：PKCS #12: Personal Information Exchange Syntax Standard

PKCS12Store中方法load()和save()，加载和保存证书，其中的实现比较复杂，处理过程主要是对PKCS12证书内容的一组SafeBag进行判断和解包。一个PKCS12结构分析的文档：http://cid-780607117452312e.office.live.com/self.aspx/.Public/PKCS%5E3l2%E7%BB%93%E6%9E%84%E5%88%86%E6%9E%90.pdf

AsymmetricKeyEntry中封装了私钥，支持属性包的附加，attributeBag，可以方便获得私钥或封装私钥

类似的，X509CertificateEntry封装了公钥证书，支持属性包的附加和x509certificateV3的扩展，可以从中方便获得公钥等

这样，就可以通过产生一个pfx证书，保存CA的密钥对。这里pfx的certBag中证书采用的是x509certificateV1格式，因为没有用到v3格式证书的扩展

思路如下：

1、产生一对密钥对，其产生方法和保存方法之前有说过

     产生密钥对：用Bouncy Castle的C#版API产生公钥和私钥

     保存方法：在C#中保存Bouncy Castle生成的密钥对

2、配置自定义的x509Name对象，BouncyCastle中采用HashTable这种结构。

3、X509CertificateEntry封装公钥证书时，添加一个该公钥证书的alias。在测试过程（测试2）中，我导入该pfx证书到电脑的当前用户my证书存储区中，用微软的接口去读取时，用FriendlyName（就是该alias）来查找比较方便。另外（测试1），在store.Aliases这个属性去查找相匹配的alias，然后通过该alias从store中获取AsymmetricKeyEntry和X509CertificateEntry，从而获取私钥和公钥。

     属性包FriendlyName，RSA的pkcs#9文档中提到过，不过不详细。链接：PKCS #9: Selected Attribute Types

     另外，上面提到的属性包attributeBag和SafeBag，BouncyCastle中的PkcsObjectIdentifiers这个源代码中全部定义，可以参考下，其命名空间为：Org.BouncyCastle.Asn1.Pkcs.PkcsObjectIdentifiers(根据该命名空间的命名方式，可以在源代码中快速定位到该源文件)

生成的代码：

char[] passwd = "123456".ToCharArray();   //pfx密码
IAsymmetricCipherKeyPairGenerator keyGen = GeneratorUtilities.GetKeyPairGenerator("RSA");
RsaKeyGenerationParameters genPar = new RsaKeyGenerationParameters(
    BigInteger.ValueOf(0x10001), new SecureRandom(), 2048, 25);
keyGen.Init(genPar);
AsymmetricCipherKeyPair keypair = keyGen.GenerateKeyPair();
RsaKeyParameters pubKey = (RsaKeyParameters)keypair.Public; //CA公钥
RsaKeyParameters priKey = (RsaKeyParameters)keypair.Private;    //CA私钥
Hashtable attrs = new Hashtable();
ArrayList order = new ArrayList();
attrs.Add(X509Name.C, "CN");    //country code
//attrs.Add(X509Name.ST, "Guangdong province");   //province name
//attrs.Add(X509Name.L, "Guangzhou city");    //locality name
attrs.Add(X509Name.O, "South China Normal University"); //organization
attrs.Add(X509Name.OU, "South China Normal University");    //organizational unit name
attrs.Add(X509Name.CN, "CAcert");   //common name
attrs.Add(X509Name.E, "popozhude@qq.com");
order.Add(X509Name.C);
//order.Add(X509Name.ST);
//order.Add(X509Name.L);
order.Add(X509Name.O);
order.Add(X509Name.OU);
order.Add(X509Name.CN);
order.Add(X509Name.E);
X509Name issuerDN = new X509Name(order, attrs);
X509Name subjectDN = issuerDN;  //自签证书，两者一样
X509V1CertificateGenerator v1certGen = new X509V1CertificateGenerator();
v1certGen.SetSerialNumber(new BigInteger(128, new Random()));   //128位
v1certGen.SetIssuerDN(issuerDN);
v1certGen.SetNotBefore(DateTime.UtcNow.AddDays(-1));
v1certGen.SetNotAfter(DateTime.UtcNow.AddDays(365));
v1certGen.SetSubjectDN(subjectDN);
v1certGen.SetPublicKey(pubKey); //公钥
v1certGen.SetSignatureAlgorithm("SHA1WithRSAEncryption");
Org.BouncyCastle.X509.X509Certificate CAcert = v1certGen.Generate(priKey);
CAcert.CheckValidity();
CAcert.Verify(pubKey);

//属性包
/*
Hashtable bagAttr = new Hashtable();
bagAttr.Add(PkcsObjectIdentifiers.Pkcs9AtFriendlyName.Id,
    new DerBmpString("CA's Primary Certificate"));
bagAttr.Add(PkcsObjectIdentifiers.Pkcs9AtLocalKeyID.Id,
    new SubjectKeyIdentifierStructure(pubKey));

X509CertificateEntry certEntry = new X509CertificateEntry(CAcert,bagAttr);
*/
X509CertificateEntry certEntry = new X509CertificateEntry(CAcert);
Pkcs12Store store = new Pkcs12StoreBuilder().Build();
store.SetCertificateEntry("CA's Primary Certificate", certEntry);   //设置证书
X509CertificateEntry[] chain = new X509CertificateEntry[1];
chain[0] = certEntry;
store.SetKeyEntry("CA's Primary Certificate", new AsymmetricKeyEntry(priKey), chain);   //设置私钥
FileStream fout = File.Create("CA.pfx");
store.Save(fout, passwd, new SecureRandom());   //保存
fout.Close();

测试1 ，把生成的pfx证书导入到计算机的证书store中，用微软提供的api去查找该证书。怎么通过MMC的证书管理单元对证书存储区进行管理：在MMC的证书管理单元中对证书存储区进行管理

X509Store store = new X509Store(StoreName.My, StoreLocation.CurrentUser);
            store.Open(OpenFlags.ReadOnly);
            X509Certificate2Collection storeCollection = (X509Certificate2Collection)store.Certificates;
            X509Certificate2 x509cert = null;
            foreach (X509Certificate2 cert in storeCollection)
            {
                //if(cert.Subject==" E = popozhude@qq.com, CN = CAcert, OU = South China Normal University, O = South China Normal University, C = CN")
                if (cert.FriendlyName == "CA's Primary Certificate")
                {
                    x509cert = cert;
                    //break;
                }
            }
            store.Close();
            if (x509cert == null)
            {
                Console.WriteLine("找不到指定的证书");
            }
            Console.WriteLine(x509cert.ToString());
            Console.ReadLine();

测试2 ：读取本地的pfx证书，获取其公钥和私钥，这里主要用BouncyCastle的API，然后又把公钥证书转换成byte数组，再用微软的证书类api读取，成功。

FileStream fs = File.OpenRead("CA.pfx");      //debug文件夹下的证书
            char[] passwd = "123456".ToCharArray();
            Pkcs12Store store = new Pkcs12StoreBuilder().Build();
            store.Load(fs, passwd); //加载证书
            string alias = null;
            foreach (string str in store.Aliases)
            {
                if (store.IsKeyEntry(str))
                    alias = str;
            }
            if (alias == null)
            {
                Console.WriteLine("alias 为空");
            }
            else
                Console.WriteLine(alias);
            AsymmetricKeyEntry keyEntry = store.GetKey(alias);
            RsaKeyParameters priKey = (RsaKeyParameters)keyEntry.Key;   //取得私钥
            X509CertificateEntry certEntry = store.GetCertificate(alias);
            Org.BouncyCastle.X509.X509Certificate x509cert = certEntry.Certificate;
            RsaKeyParameters pubKey = (RsaKeyParameters)x509cert.GetPublicKey();    //取得公钥
            x509cert.Verify(pubKey);    //test ok
            byte[] certByte = x509cert.GetEncoded();    //把该证书转换成字节数组
            X509Certificate2 cert2 = new X509Certificate2(certByte);    //微软的类X509Certificate2
            Console.WriteLine(cert2.ToString());    //显示正常，说明可以把BouncyCastle产生的数字v3证书，转换成X509Certificate2处理的证
            Console.Read();