Winhttp and p12 certificate

Question

I am writing a client program in VB6 which will interface to a server over HTTP. The company who runs the server provided me with a certificate file called SomeCertificate.p12.

My program is running on Windows XP. This is the operating system the customer is using.

I am trying to find how to use this certificate when sending requests to the server.

Here is what I have done so far:

1. Copied the certificate file to my test computer.
2. Using Internet Explorer V8, I did "Tools|Internet Options|Content|Certificates|Trusted Root Authorities" and imported the certificate.
3. Installed the winhttpcertcfg tool.

4. Ran the following from command prompt:

   "winhttpcertcfg -i SomeCertificate.p12 -c LOCAL_MACHINE\My -a COMPUTERNAME\USERNAME -p PasswordFromServerCompany"

the output was something like this. I replaced the different tokens with dummy strings:

Imported certificate:

CN=string1

OU=string2

O=string3

L=string4

C=string5

Private key access has already been granted for account: COMPUTERNAME\USERNAME

6. My VB6 code looks something like this:

   Private WithEvents m_ServerObj As WinHttpRequest Set m_ServerObj = New WinHttpRequest m_ServerObj.Open "GET", "https://serveraddress"

   Call m_ServerObj.SetClientCertificate("LOCAL_MACHINE\Personal\SomeCertificate")

   m_ServerObj.Send TextToSend

The Send call causes an exception: "A certificate is required to complete client authentication"

I tried different strings in the SetClientCertificate call but I keep getting the same error.

I'd appreciate any help and tips. What am i doing wrong? Is my code wrong? Did I use winhttpcertcfg incorrectly?

thank you.

Answer 1

The server company sent me a .PEM certificate to install. Once I did that, the problem was solved. Thank you.