Phew...  Glad it was not just me.

In my workaround i posted the Base64 to hex code i use.. Does .NET2 or WSE have a method to do this.  I can convert a string to/from base64 easily but i have yet to find a base64 to hex.

 Hi Ste,
 Yes, I also reported that problem.
 This X509 API doesn't allow to do a indexed search by KeyIdentifier so WSE has to do a sequential search, which can take a lot of time to complete if you have many certificates in your store.
 In your case, WSE is doing a sequential search against 85 certificates.
 Anyway, WSE keeps the certificate in a caches after finding it and therefore it only takes a lot of time the first time.

 Regards,
 Pablo Cibraro
 http://weblogs.asp.net/cibrax
 http://www.lagash.com

 "Ste" <noemail@nospam.com> wrote in message news:wJ-dnbFQWeMtfifeRVny1w@pipex.net...
   X509Util.FindCertificateByKeyIdentifier() takes an extraordinary amount of time to complete.  On my system it is taking in excess of 5 minutes to complete.
   I only have 85 certificates in the store.

   Is this expected behaviour?

       string keyIdentifier = Convert.FromBase64String("7CwyLoUNwbbjJwx5oX75Af1cQEs=");
       X509Certificate2Collection certs2 = X509Util.FindCertificateByKeyIdentifier(keyIdentifier, StoreLocation.LocalMachine, StoreName.Root.ToString());

   The FindCertificateBySubjectName() call completes instantaneously!

   If i open the store via X509Store and invoke the find method on certificate collection, it returns immediately!

   What is the recommended method for finding certificates in a store, X509Util or X509Certificate2Collection ?

   X509 store code pasted below ..........

             // convert the base64 string to the hexadecimal equivalent
             byte[] b = Convert.FromBase64String("7CwyLoUNwbbjJwx5oX75Af1cQEs=");
             char[] h = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F' };
             char[] c = new char[b.Length * 2];
             for (int i = 0; i < b.Length; i++)
             {
               c[i*2+0] = h[b[i] >> 4];
               c[i*2+1] = h[b[i] & 0xF];
             }
             string keyId = new string(c);

             // now open the store
             X509Store store = null;
             try
             {
                 store = new X509Store(StoreName.Root, StoreLocation.CurrentUser);
                 store.Open(OpenFlags.ReadOnly | OpenFlags.OpenExistingOnly);

                 X509Certificate2Collection found = store.Certificates.Find(X509FindType.FindBySubjectKeyIdentifier, keyId, true);

                 if (found.Count != 1)
                 {
                    throw new ApplicationException("The certificate specified cannot be identified by the keyId " + keyId);

                 }
                 return found[0];

             }
             finally
             {
                 store.Close();
             }