Hi all, The other day a colleague of mine was trying to renew his smart card certificate, but he got an error telling him that there was not enough space in the card to store the new cert. So he asked me: Alex, how can I delete a certificate from my...

Hi all, When executing RSACryptoServiceProvider.Encrypt method (see How to generate key pairs, encrypt and decrypt data with .NET (C#) for an example), you may get a System.Security.Cryptography.CryptographicException . According to MSDN , this is...

Hi all, The other day a colleague of mine asked me if I had a .NET version of the C++ sample in How to generate key pairs, encrypt and decrypt data with CryptoAPI post. C++ sample calls CryptoAPI directly (and you know we can do the same thing in ...

Hi all, Sorry I haven't been able to write anything for a few weeks. I've been on vacation + paternity leave... Paternity leave! Yes, I'm a father now! My son Nicolas was born on Sept 11th, 2008, and he's taken pretty much all my free time since. WELCOME...

Hi all, The other day I was working with a customer of mine on a .NET application which was suffering from a memory leak . The weird thing was that the application could run just fine for 10 days in a row before the memory began growing and growing...

Hi all, The other day I was trying to add a simple autoupdate functionality to a little tool I developed, and I needed to check the version of current assembly against the udpated one. If current assembly was older than the updated one, I needed to...

Hi all, The following C# sample shows how to use CertEnroll COM component to create a certificate request , send the request to the CA , get the response from the CA , and install the new certificate in the machine: (Note that this sample is a WinForms...

Hi all, If you ever try to use XEnroll.dll in your ASP.NET application (through Interop.XENROLLLib.dll , of course), you may face an issue like the following: Your ASP.NET app impersonates the client user and tries to make a certificate request...

Hi all, If you want to know how to debug a Windows service , the following article will be of great assistance: How to debug Windows services . I suggest you read this article before you continue reading this post. Also, you should have Debugging Tools...

Hi all, We may have a group in our Active Directory with members from a foreign domain . We may try to retrieve all those members with ADSI and a code like this: Using IADs::GetInfoEx for Range Retrieval . The issue with this code is that we will only...

Hi all, In some situations we may need to reference a COM dll in our Visual Studio project in order to use a specific COM object within our .NET application, and thanks to COM Interop we can do it. When we add a reference to a COM dll in our project...

Hi all, When working with RSACryptoServiceProvider , we may get an exception like the following: System.Security.Cryptography. CryptographicException : Unable to open the access token of the current thread at System.Security.Cryptography.CryptographicException...

Hi all, The other day I had to troubleshoot an issue with a process that a specific Windows service was trying to launch without success. We could see with a debugger (i.e. WinDbg) that the new process was actually being created but it exited before...

Hi all, Imagine we are running a 32bit .NET app in a x64 machine . This app is failing so we have taken a memory dump of the app when a specific CLR exception gets raised. We open the dump with our 64bit version of Windbg ( Windbg x64 ), and we...

Hi all, When using RSACryptoServiceProvider in i.e. ASP.NET you may get the following exception under a heavy load scenario: "System.Security.Cryptography.CryptographicException: CryptoAPI cryptographic service provider (CSP) for this implementation...

Hi all, Let's talk a bit about concurrency in CryptoAPI . When calling CryptoAPI from different threads , we have to take into consideration that key handles are not thread safe . The following document describes the threading issues when dealing...

Hi all, You may be trying to install a hotfix or update silently , but you keep getting a security warning dialog because the file was downloaded from the Internet . The following article explains this situation: 889815 The Open File - Security Warning...

Hi all, Today I'm posting a sample which shows how to sign a text with a certificate in my Personal store (this cert will have public and private key associated to it) and how to verify that signature with a .cer file (for i.e. WinForms) applications...

Hi all, You may get an Access Denied error ( COMException 0x80070005 ) when using System.DirectoryServices.DirectorySynchronization in your .NET application with a non-admin user , but everything works fine with a domain administrator. This issue...

Hi all, If you ever use WMI Diag script ( The WMI Diagnosis Utility -- Version 2.0 ) on a non-English version of Windows (i.e. Spanish , French, Italian, German...), you will get tons of errors when the script checks out default permissions on WMI...

Hi all, Some customers asked me in the past if there was any API to verify if a password meets Windows complexity requirements . Unfortunately there is no such API. We could implement our own if we know the requirements of the password filter used...

Hi all, If you read CryptAcquireContext documentation, you'll see that setting pszContainer to NULL allow us to use a default key container . Microsoft recommends that every application creates its own key container instead of the default one, because...

Hi all, When we try to access a key container, CryptAcquireContext may return NTE_BAD_KEYSET (or error # 0x80090016 or -2146893802 or "Keyset does not exist") for the following two reasons: 1) key container doesn't exist . You may repeat the call...

Hi all, welcome back, The following .NET 2.0 sample shows how to get security info from a folder to find out the permissions for users/groups on it: using System; using System.IO; using System.Security.AccessControl; using System.Security.Principal;...

Hi all, welcome back, CryptAcquireContext API will fail with error #2 or ERROR_FILE_NOT_FOUND if: 1) the user's profile is not loaded, as we saw in my post RSACryptoServiceProvider fails when used with ASP.NET . 2) AppData registry value in the...