How do you thumbprint a certificate?

You often use thumbprints to find certificates, but what is the thumbprint?  The thumbprint is the hash of the certificate. In the case of the CLR’s X509Certificate2 class, the thumbprint is the SHA1 hash of the certificate. If you want to compute the thumbprint of a certificate yourself it’s pretty simple:

 
function get-CertThumbprint ($cert)
{
	$sha = new-object System.Security.Cryptography.SHA1CNG
	$hashOfRawBytesOfCertificate = $sha.ComputeHash($cert.RawData)
	( $hashOfRawBytesOfCertificate| % {"{0:X}" -f $_} ) -join ""
}
 
PS cert:\LocaLMachine\My> dir


    Directory: Microsoft.PowerShell.Security\Certificate::LocaLMachine\My


Thumbprint                                Subject
----------                                -------
3BCA8A25A071300BD177E4C73135E54FA830039A  CN=STS
08766D8B3DCDE5D633ED06AB1CB4DF4CCAECA533  CN=localhost

PS cert:\LocalMachine\My> $cert = get-item 08766D8B3DCDE5D633ED06AB1CB4DF4CCAECA533
PS cert:\LocalMachine\My> $cert.Thumbprint
08766D8B3DCDE5D633ED06AB1CB4DF4CCAECA533
PS cert:\LocalMachine\My> get-CertThumbprint $cert
8766D8B3DCDE5D633ED6AB1CB4DF4CCAECA533

If you’re wondering why you don’t use the subject name to identify a certificate, it’s because you can have lots of certificates with the same subject name.

Comments

Unknown said…
Life isn't about finding yourself. Life is about creating yourself. See the link below for more info.


#yourself
www.ufgop.org
12/09/2015 11:08 PM
Post a Comment

Popular posts from this blog

Finding CLR exceptions without visual studio

(If you want to understand what exception code 0xe0434352 is, read this post ) Often exceptions are thrown and caught and you don't see them. You probably know how to debug this in Visual Studio, so let me show you how to do it in cdb. Sample Code: class Program { static void Main(string[] args) { foreach (var x in Enumerable.Range(0,2000)) { Thread.Sleep(TimeSpan.FromSeconds(1)); Console.WriteLine("Hello World"); ThrowAndCatchException(); } } private static void ThrowAndCatchException() { try { throw new NotImplementedException(); } catch(Exception) { } } } Output of the application: Hello World Hello World Hello World Nothing about an exception, but you're sure it's happening behind the covers -- fire up cdb: C:\Program Files\Debugging Tools for Windows (x64)>cdb -pn consoleapplication3.exe <SNIP> ModLoad: 000007fe`f7e90000 000007fe`f7eb4000 C:\Windows\Mi
Read more

Why do I keep getting exception code e0434352?

If you want to know how to debug CLR exceptions using cdb then read this post . Exception code e0434352 is the exception code used internally by the CLR to represent most exceptions(*). Regardless of if you throw a System.NullReferenceException or a System.ArgumentException in C#, you'll throw a SEH exception e0434352 under the covers. A fun way to validate this theory is to watch what happens to the CLR exceptions settings in cdb. Fire up cdb, and see the state of clr exceptions: 0:000> .shell -ci "sx" findstr clr clr - CLR exception - second-chance break - not handled clrn - CLR notification exception - break - handled .shell: Process exited Now, set the exception handler for exception number e0434352 and recheck the value of the clr exception handler: 0:000> sxe e0434352 0:000> .shell -ci "sx" findstr clr clr - CLR exception - break - not handled clrn - CLR notification exception - break - handled .shell: Process exited Armed with
Read more

Powershell script to enable windows to capture localhost traffic in wireshark

If you want to understand why the following scripts work read this post . Otherwise just paste the following into an elevated powershell window: Setup windows networking to allow localhost capturing in wireshark: # Find the network configuration that has the default gateway. $defaultAdapter = Get-WMIObject Win32_NetworkAdapterConfiguration | ? {$_.DefaultIPGateway} if (@($defaultAdapter).Length -ne 1) {throw "You don't have 1 default gateway, your network configuration is not supported" } # Route local IP address via the default gateway route add $defaultAdapter.IPAddress[0] $defaultAdapter.DefaultIPGateway Write-Host "Start capturing on localhost by connecting to $($defaultAdapter.IPAddress[0])" Return windows networking to normal configuration: # Find the network configuration that has the default gateway. $defaultAdapter = Get-WMIObject Win32_NetworkAdapterConfiguration | ? {$_.DefaultIPGateway} if (@($defaultAdapter).Length -ne 1) {throw "Y
Read more