(VB.NET) Sign a File to Create a .p7s (Detached Signature)

VB.NET 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.

Note: This example requires Chilkat v10.1.2 or greater.

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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 jsonCN As New Chilkat.JsonObject
jsonCN.UpdateString("CN",signingCertSubject)

Dim cert As New Chilkat.Cert
success = certStore.FindCert(jsonCN,cert)
If (success = 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 .p7s as output:
Dim inFile As String = "/Users/chilkat/testData/pdf/sample.pdf"
Dim sigFile As String = "/Users/chilkat/testData/p7s/sample.p7s"

success = crypt.CreateP7S(inFile,sigFile)
If (success = False) Then
    Debug.WriteLine(crypt.LastErrorText)
    Exit Sub
End If


success = crypt.VerifyP7S(inFile,sigFile)
If (success = False) Then
    Debug.WriteLine(crypt.LastErrorText)
    Exit Sub
End If


Debug.WriteLine("Success!")