Check if Certificate Expired

How to check to see if a digital certificate is expired.

Download Chilkat .NET for 2.0 Framework

Download Chilkat .NET for 1.0 / 1.1 Framework

Dim cert As New Chilkat.Cert()
Dim isExpired As Boolean

'  The LoadByCommonName method searches the registry-based
'  Windows Current User Certificate Store and Local Machine Certificate
'  Store for a certificate whose common name (CN) matches
'  the argument:
Dim success As Boolean
success = cert.LoadByCommonName("Chilkat Software, Inc.")
If (success = false) Then
    MsgBox("Failed to find certificate!")
Else

    '  Display the certificate's distinguished name:
    TextBox1.Text = TextBox1.Text & cert.SubjectDN & vbCrLf



    isExpired = cert.Expired
    If (isExpired = true) Then
        TextBox1.Text = TextBox1.Text & "Certificate is expired." & vbCrLf
    Else
        TextBox1.Text = TextBox1.Text & "Certificate is NOT expired." & vbCrLf
    End If


End If


'  Alternatively, load a Certificate from a .cer file.
'  (Certs may also be loaded from other types of files, such as PEM, DER, PFX, etc.)
success = cert.LoadFromFile("myCert.cer")
If (success = false) Then
    MsgBox("Failed to load certificate!")
Else

    '  Display the certificate's distinguished name:
    TextBox1.Text = TextBox1.Text & cert.SubjectDN & vbCrLf



    isExpired = cert.Expired
    If (isExpired = true) Then
        TextBox1.Text = TextBox1.Text & "Certificate is expired." & vbCrLf
    Else
        TextBox1.Text = TextBox1.Text & "Certificate is NOT expired." & vbCrLf
    End If


End If


'  The Chilkat Certificate, Certificate Store, Private Key,
'  Public Key, and Key Container classes / objects are freeware.

'  They are used by and included with the Chilkat Email,
'  Crypt, S/MIME, and other commercial Chilkat components.