(Visual Basic 6.0) Find Certificate by Email Address

See more Cert Store Examples

Demonstrates how to find a certificate having the specified email address either within the cert's subject email, or the RFC822 name.

In an X.509 certificate, an email address can typically be located in two places:

1. RFC822 Name (Subject Alternative Name extension) -
   • The certificate may include an email address in the Subject Alternative Name (SAN) extension under the RFC822 Name field. This is a modern and preferred method because it allows for flexibility and alignment with security best practices.
   • To find it, Chilkat inspects the SAN extension in the certificate details.
2. Subject (Common Name or Email Address attribute) -
   • Older certificates may store the email address directly in the Subject field, typically under the Email Address attribute ("emailAddress") or, less commonly, the Common Name (CN).
   • This method is less preferred in modern standards but can still be encountered in legacy implementations. Chilkat also searches here for the email address.

Note: Requires Chilkat v10.1.2 or later.

Chilkat ActiveX Downloads ActiveX for 32-bit and 64-bit Windows

Dim certStore As New ChilkatCertStore

' This opens the Current User certificate store on Windows,
' On MacOS and iOS it opens the default Keychain.
Dim readOnly As Long
readOnly = 0
Dim success As Long
success = certStore.OpenCurrentUserStore(readOnly)
If (success = 0) Then
    Debug.Print certStore.LastErrorText
    Exit Sub
End If

' Find the certificate having the specified email address in either the RFC822 Name or in the Subject.
Dim json As New ChilkatJsonObject
Dim email_address As String
email_address = "joe@example.com"
success = json.UpdateString("email",email_address)

Dim cert As New ChilkatCert
success = certStore.FindCert(json,cert)
If (success = 1) Then
    ' Show the full distinguished name of the certificate.
    Debug.Print "Found: " & cert.SubjectDN
Else
    Debug.Print "Not found."
End If