Extract properties from a CRL file using C#

Question

I'd like to write a program which monitors CRL (Certificate Revocation List) expiration date. Therefore, I'd like to read the following properties from a CRL file: 1) Effective Date 2) Next Update 3) Next CRL Publish

How can I accomplish my task? I've only managed to find types for X509Certificate2, X509Chain, x509RevocationMode etc..

Answer 1

you can use the class X509Certificate2 to get information needed.

example:To handle one certification file

X509Certificate2 x509 = new X509Certificate2();
byte[] rawData = ReadFile(fname);
x509.Import(rawData);
var validDate= x509 . NotBefore;    
var expireDate = x509.NotAfter;


//Reads a file.
internal static byte[] ReadFile (string fileName)
{
    FileStream f = new FileStream(fileName, FileMode.Open, FileAccess.Read);
    int size = (int)f.Length;
    byte[] data = new byte[size];
    size = f.Read(data, 0, size);
    f.Close();
    return data;
}

reference:

https://msdn.microsoft.com/en-us/library/system.security.cryptography.x509certificates.x509certificate2(v=vs.110).aspx

Edit:

You can use the BouncyCastle.Crypto library to handle CRL. Download the library and reference the BouncyCastle.Crypto.dll or instal the nuget package:

Install-Package BouncyCastle


  //reference library BouncyCastle.Crypto
  //http://www.bouncycastle.org/csharp/
  //Load CRL file and access its properties
    public void  GetCrlInfo(string fileName, Org.BouncyCastle.Math.BigInteger serialNumber, Org.BouncyCastle.X509.X509Certificate cert)
    {
        try
        {
            byte[] buf = ReadFile(fileName);
            X509CrlParser xx = new X509CrlParser();
            X509Crl ss = xx.ReadCrl(buf);
            var nextupdate = ss.NextUpdate;
            var isRevoked = ss.IsRevoked(cert);
            Console.WriteLine("{0} {1}",nextupdate,isRevoked);
        }
        catch (Exception ex)
        {
            Console.WriteLine(ex.Message);
        }
    }