(Visual Basic 6.0) Sign a File to Create a .p7m File (using a PFX)

Visual Basic 6.0 example to sign a file creating a .p7m file as output. The .p7m contains the signed contents of the original file. It can be verified and restored by calling VerifyP7M.

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 .p7m as output:
Dim inFile As String
inFile = "/Users/chilkat/testData/pdf/sample.pdf"
Dim outputFile As String
outputFile = "/Users/chilkat/testData/p7m/sample.pdf.p7m"
success = crypt.CreateP7M(inFile,outputFile)
If (success = 0) Then
    Debug.Print crypt.LastErrorText

    Exit Sub
End If

' Verify and restore the original file:
success = crypt.SetVerifyCert(cert)

inFile = outputFile
outputFile = "/Users/chilkat/testData/pdf/restored.pdf"

success = crypt.VerifyP7M(inFile,outputFile)
If (success = 0) Then
    Debug.Print crypt.LastErrorText

    Exit Sub
End If

Debug.Print "Success!"