(Visual Basic 6.0) Sign a File to Create a .p7s (Detached Signature)

Visual Basic 6.0 example to create a detached signature file (.p7s) for any type file. The signature can be verified by calling VerifyP7S and passing the original filename and the .p7s filename.

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

' This example requires the Chilkat API to have been previously unlocked.
' See Global Unlock Sample for sample code.

Dim crypt As New ChilkatCrypt2

' Use a digital certificate and private key from a PFX file (.pfx or .p12).
Dim signingCertSubject As String
signingCertSubject = "Acme Inc"
Dim pfxFilename As String
pfxFilename = "/Users/chilkat/testData/pfx/acme.pfx"
Dim pfxPassword As String
pfxPassword = "test123"

Dim certStore As New ChilkatCertStore
Dim success As Long
success = certStore.LoadPfxFile(pfxFilename,pfxPassword)
If (success <> 1) Then
    Debug.Print certStore.LastErrorText
    Exit Sub
End If

Dim cert As ChilkatCert
Set cert = certStore.FindCertBySubjectCN(signingCertSubject)
If (certStore.LastMethodSuccess = 0) Then
    Debug.Print "Failed to find certificate by subject common name."
    Exit Sub
End If

' Tell the crypt component to use this cert.
success = crypt.SetSigningCert(cert)

' We can sign any type of file, creating a .p7s as output:
Dim inFile As String
inFile = "/Users/chilkat/testData/pdf/sample.pdf"
Dim sigFile As String
sigFile = "/Users/chilkat/testData/p7s/sample.p7s"

success = crypt.CreateP7S(inFile,sigFile)
If (success = 0) Then
    Debug.Print crypt.LastErrorText

    Exit Sub
End If

success = crypt.VerifyP7S(inFile,sigFile)
If (success = 0) Then
    Debug.Print crypt.LastErrorText

    Exit Sub
End If

Debug.Print "Success!"