(VB.NET) Sign a File to Create a .p7m File (using a PFX)

VB.NET 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.

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

Dim crypt As New Chilkat.Crypt2


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

Dim certStore As New Chilkat.CertStore
Dim success As Boolean = certStore.LoadPfxFile(pfxFilename,pfxPassword)
If (success <> True) Then
    Debug.WriteLine(certStore.LastErrorText)
    Exit Sub
End If


Dim cert As Chilkat.Cert
cert = certStore.FindCertBySubjectCN(signingCertSubject)
If (certStore.LastMethodSuccess = False) Then
    Debug.WriteLine("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 = "/Users/chilkat/testData/pdf/sample.pdf"
Dim outputFile As String = "/Users/chilkat/testData/p7m/sample.pdf.p7m"
success = crypt.CreateP7M(inFile,outputFile)
If (success = False) Then
    Debug.WriteLine(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 = False) Then
    Debug.WriteLine(crypt.LastErrorText)

    Exit Sub
End If




Debug.WriteLine("Success!")