恐怕无法通过使用标准 .NET API 来检测读卡器中是否存在包含特定 X509Certificate2 对象的卡。我能想到的最好的东西（非常老套）是这样的：
public static X509Certificate2 GetDefaultCertificateStoredOnTheCard()
{
// Acquire public key stored in the default container of the currently inserted card
CspParameters cspParameters = new CspParameters(1, "Microsoft Base Smart Card Crypto Provider");
RSACryptoServiceProvider rsaProvider = new RSACryptoServiceProvider(cspParameters);
string pubKeyXml = rsaProvider.ToXmlString(false);
// Find the certficate in the CurrentUser\My store that matches the public key
X509Store x509Store = new X509Store(StoreName.My, StoreLocation.CurrentUser);
x509Store.Open(OpenFlags.ReadOnly | OpenFlags.OpenExistingOnly);
foreach (X509Certificate2 cert in x509Store.Certificates)
{
if ((cert.PublicKey.Key.ToXmlString(false) == pubKeyXml) && cert.HasPrivateKey)
return cert;
}
return null;
}
但是这种方法只有在满足以下条件时才可靠：
- 您的卡可通过微型驱动程序和 Microsoft Base Smart Card Crypto Provider 访问。
- 只有一个读卡器连接到您的计算机且存在智能卡。
- 当前插入读卡器的卡上只有一张证书。
当有多个读卡器连接了智能卡或卡上存在多个证书时，您无法确定此方法将返回哪一个。
请注意，还有其他可用的 API 可以访问智能卡。这种 API 的一个示例是 PKCS#11。对于简单的操作来说，这可能是一种过度杀伤，但它可以让您完全控制您的卡和存储在卡上的对象。如果您有兴趣并且您的智能卡带有 PKCS#11 库，您可以查看我的项目 Pkcs11Interop，它为 .NET 环境带来了 PKCS#11 API 的全部功能。
希望这会有所帮助:)
编辑删除“单一证书”限制：
我稍微修改了代码。它现在使用非托管 Crypto API 来枚举由 Microsoft Base Smart Card Crypto Provider 管理的所有容器的名称，然后在 CurrentUser\My 存储中搜索相应的 X509Certificate2 对象。请注意，这种方法也非常hackish，并且提供的代码可能无法可靠地与市场上可用的所有卡/微型驱动程序一起使用。让用户从内置的证书选择对话框中选择正确的证书通常会更好、更容易。
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Runtime.InteropServices;
using System.Security.Cryptography;
using System.Security.Cryptography.X509Certificates;
using System.Text;
namespace CSP
{
public static class BaseSmartCardCryptoProvider
{
private const string _providerName = "Microsoft Base Smart Card Crypto Provider";
private static class NativeMethods
{
public const uint PROV_RSA_FULL = 0x00000001;
public const uint CRYPT_VERIFYCONTEXT = 0xF0000000;
public const uint CRYPT_FIRST = 0x00000001;
public const uint CRYPT_NEXT = 0x00000002;
public const uint ERROR_NO_MORE_ITEMS = 0x00000103;
public const uint PP_ENUMCONTAINERS = 0x00000002;
[DllImport("advapi32.dll", BestFitMapping = false, ThrowOnUnmappableChar = true, SetLastError = true)]
public static extern bool CryptAcquireContext(
ref IntPtr phProv,
[MarshalAs(UnmanagedType.LPStr)] string pszContainer,
[MarshalAs(UnmanagedType.LPStr)] string pszProvider,
uint dwProvType,
uint dwFlags);
[DllImport("advapi32.dll", BestFitMapping = false, ThrowOnUnmappableChar = true, SetLastError = true)]
public static extern bool CryptGetProvParam(
IntPtr hProv,
uint dwParam,
[MarshalAs(UnmanagedType.LPStr)] StringBuilder pbData,
ref uint pdwDataLen,
uint dwFlags);
[DllImport("advapi32.dll", SetLastError = true)]
public static extern bool CryptReleaseContext(
IntPtr hProv,
uint dwFlags);
}
public static List<X509Certificate2> GetCertificates()
{
List<X509Certificate2> certs = new List<X509Certificate2>();
X509Store x509Store = null;
try
{
x509Store = new X509Store(StoreName.My, StoreLocation.CurrentUser);
x509Store.Open(OpenFlags.ReadOnly | OpenFlags.OpenExistingOnly);
List<string> containers = GetKeyContainers();
foreach (string container in containers)
{
CspParameters cspParameters = new CspParameters((int)NativeMethods.PROV_RSA_FULL, _providerName, container);
cspParameters.Flags = CspProviderFlags.UseExistingKey;
string pubKeyXml = null;
using (RSACryptoServiceProvider rsaProvider = new RSACryptoServiceProvider(cspParameters))
pubKeyXml = rsaProvider.ToXmlString(false);
foreach (X509Certificate2 cert in x509Store.Certificates)
{
if ((cert.PublicKey.Key.ToXmlString(false) == pubKeyXml) && cert.HasPrivateKey)
certs.Add(cert);
}
}
}
finally
{
if (x509Store != null)
{
x509Store.Close();
x509Store = null;
}
}
return certs;
}
private static List<string> GetKeyContainers()
{
List<string> containers = new List<string>();
IntPtr hProv = IntPtr.Zero;
try
{
if (!NativeMethods.CryptAcquireContext(ref hProv, null, _providerName, NativeMethods.PROV_RSA_FULL, NativeMethods.CRYPT_VERIFYCONTEXT))
throw new Win32Exception(Marshal.GetLastWin32Error());
uint pcbData = 0;
uint dwFlags = NativeMethods.CRYPT_FIRST;
if (!NativeMethods.CryptGetProvParam(hProv, NativeMethods.PP_ENUMCONTAINERS, null, ref pcbData, dwFlags))
throw new Win32Exception(Marshal.GetLastWin32Error());
StringBuilder sb = new StringBuilder((int)pcbData + 1);
while (NativeMethods.CryptGetProvParam(hProv, NativeMethods.PP_ENUMCONTAINERS, sb, ref pcbData, dwFlags))
{
containers.Add(sb.ToString());
dwFlags = NativeMethods.CRYPT_NEXT;
}
int err = Marshal.GetLastWin32Error();
if (err != NativeMethods.ERROR_NO_MORE_ITEMS)
throw new Win32Exception(err);
if (hProv != IntPtr.Zero)
{
if (!NativeMethods.CryptReleaseContext(hProv, 0))
throw new Win32Exception(Marshal.GetLastWin32Error());
hProv = IntPtr.Zero;
}
}
catch
{
if (hProv != IntPtr.Zero)
{
if (!NativeMethods.CryptReleaseContext(hProv, 0))
throw new Win32Exception(Marshal.GetLastWin32Error());
hProv = IntPtr.Zero;
}
throw;
}
return containers;
}
}
}
只需调用所提供类的 GetCertificates() 方法即可检查此代码是否适用于您的卡：
List<X509Certificate2> certs = CSP.BaseSmartCardCryptoProvider.GetCertificates();