随着《电子签名法》的颁布,数字证书应用越来越广泛,在一般的应用中,我们都是在系统中安装pkcs12格式的证书。在访问应用(一般是网页、电子邮件等)时,选择合适的证书。我们也可以使用编程来直接读取证书文件。下面我们就介绍如何使用.net读取数字证书。
要读取pkcs12格式的证书,我们需要调用API,在WIN32类中,我们声明这些API的引用:
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using System;
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using System.Runtime.InteropServices;
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namespace X509Cert
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{
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public class WIN32
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{
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public const uint CRYPT_USER_KEYSET = 0x00001000;
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public const uint CERT_KEY_PROV_INFO_PROP_ID = 0x00000002;
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public const uint CRYPT_DELETEKEYSET = 0x00000010;
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[DllImport("crypt32.dll", SetLastError=true)]
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public static extern IntPtr PFXImportCertStore(ref CRYPT_DATA_BLOB pPfx,[MarshalAs(UnmanagedType.LPWStr)] String szPassword,uint dwFlags);
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[DllImport("CRYPT32.DLL", EntryPoint="CertEnumCertificatesInStore", CharSet=CharSet.Auto, SetLastError=true)]
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public static extern IntPtr CertEnumCertificatesInStore( IntPtr storeProvider, IntPtr prevCertContext);
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[DllImport("CRYPT32.DLL",CharSet=CharSet.Auto, SetLastError=true)]
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public static extern bool CertGetCertificateContextProperty(IntPtr pCertContext,uint dwPropId,IntPtr pvData,ref uint pcbData);
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[DllImport("advapi32.dll",EntryPoint="CryptAcquireContext",CharSet=CharSet.Auto, SetLastError=true)]
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public static extern bool CryptAcquireContext(ref IntPtr phProv,string szContainer,string szProvider,uint dwProvType,uint dwFlags);
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[StructLayout(LayoutKind.Sequential)]
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public struct CRYPT_DATA_BLOB {
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public int cbData;
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public IntPtr pbData;
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}
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[StructLayout(LayoutKind.Sequential)]
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public struct CRYPT_KEY_PROV_INFO {
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[MarshalAs(UnmanagedType.LPWStr)]
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public String ContainerName;
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[MarshalAs(UnmanagedType.LPWStr)]
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public String ProvName;
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public uint ProvType;
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public uint Flags;
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public uint ProvParam;
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public IntPtr rgProvParam;
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public uint KeySpec;
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}
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public WIN32()
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{
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//
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// TODO: 在此处添加构造函数逻辑
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//
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}
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}
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}
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然后在Cert类中写一个Read方法读取其中的证书。注意:pfx文件有可能包含几个证书
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using System;
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using System.IO;
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using System.Runtime.InteropServices;
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using System.Security.Cryptography.X509Certificates;
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namespace X509Cert
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{
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/// <summary>
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/// Cert 的摘要说明。
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/// </summary>
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public class Cert
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{
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public Cert()
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{
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//
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// TODO: 在此处添加构造函数逻辑
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//
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}
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public static System.Security.Cryptography.X509Certificates.X509Certificate[] Read(string filename,string password) {
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//打开证书文件,并读到一个字节数组中。
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FileStream stream = new FileStream(filename,FileMode.Open);
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byte[] buffer = new byte[stream.Length];
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stream.Read(buffer,0,buffer.Length);
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stream.Close();
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//声明并实例化WIN32.CRYPT_DATA_BLOB 将读取到的字节数组拷贝到它的pbData属性中。将字节数组长度赋给cbData属性
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WIN32.CRYPT_DATA_BLOB cryptdata = new WIN32.CRYPT_DATA_BLOB();
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cryptdata.cbData = buffer.Length;
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cryptdata.pbData = Marshal.AllocHGlobal(cryptdata.cbData);
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Marshal.Copy(buffer,0,cryptdata.pbData,buffer.Length);
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IntPtr hMemStore = WIN32.PFXImportCertStore(ref cryptdata,"1234",WIN32.CRYPT_USER_KEYSET);
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Marshal.FreeHGlobal(cryptdata.pbData);
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uint provinfosize = 0;
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WIN32.CRYPT_KEY_PROV_INFO certinfo = new WIN32.CRYPT_KEY_PROV_INFO();
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System.Collections.ArrayList certs = new System.Collections.ArrayList();
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IntPtr certHandle = IntPtr.Zero;
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while((certHandle = WIN32.CertEnumCertificatesInStore(hMemStore,certHandle)) != IntPtr.Zero) {
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if(WIN32.CertGetCertificateContextProperty(certHandle,WIN32.CERT_KEY_PROV_INFO_PROP_ID,IntPtr.Zero,ref provinfosize)){
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IntPtr info = Marshal.AllocHGlobal((int)provinfosize);
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if(WIN32.CertGetCertificateContextProperty(certHandle,WIN32.CERT_KEY_PROV_INFO_PROP_ID,info,ref provinfosize)) {
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certinfo = (WIN32.CRYPT_KEY_PROV_INFO)Marshal.PtrToStructure(info,typeof(WIN32.CRYPT_KEY_PROV_INFO));
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certs.Add(new X509Certificate(certHandle));
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}
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Marshal.FreeHGlobal(info);
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}
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}
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Marshal.FreeHGlobal(hMemStore);
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IntPtr hCryptProv = IntPtr.Zero;
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if(!WIN32.CryptAcquireContext(ref hCryptProv,certinfo.ContainerName,certinfo.ProvName,certinfo.ProvType,WIN32.CRYPT_DELETEKEYSET))
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throw new Exception("释放内存错误");
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return (X509Certificate[])certs.ToArray(typeof(X509Certificate));
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}
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}
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}
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