(VB.NET) Create CMS (PKCS7) Detached MIME Signature

Demonstrates how to add a CMS detached signature to MIME.

Chilkat .NET Downloads Chilkat .NET Framework Chilkat for .NET Core

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


Dim mime As New Chilkat.Mime

' Load a certificate w/ private key for signing.
Dim cert As New Chilkat.Cert
Dim success As Boolean = cert.LoadPfxFile("qa_data/pfx/ecc256_12345.p12","12345")
If (success <> True) Then
    Debug.WriteLine(cert.LastErrorText)
    Exit Sub
End If


Debug.WriteLine("Cert: " & cert.SubjectDN)

' Create a simple MIME message to be signed:
mime.AddHeaderField("Subject","This is a test")
mime.AddHeaderField("MyCustomHeader","abc123")
mime.ContentType = "text/plain"
mime.SetBody("This is a plain-text body.")

' Examine the MIME prior to signing:
Debug.WriteLine("--- MIME prior to signing ---")
Debug.WriteLine(mime.GetMime())

' The MIME prior to signing looks like this:

' Subject: This is a test
' MyCustomHeader: abc123
' Content-Type: text/plain; format=flowed
' 
' This is a plain-text body.


' Use SHA256 as the hash algorithm in the CMS signature.
mime.SigningHashAlg = "SHA256"

' Add a detached signature:
success = mime.AddDetachedSignature(cert)
If (success = False) Then
    Debug.WriteLine(mime.LastErrorText)
    Exit Sub
End If


' Examine the MIME with detached signature:
Debug.WriteLine("--- MIME with detached signature ---")
Debug.WriteLine(mime.GetMime())

' Content-Type: multipart/signed; boundary="----=_NextPart_6e3_c655_9641494d.b4f00501";
'  protocol="application/x-pkcs7-signature";
'  micalg=sha256
' 
' ------=_NextPart_6e3_c655_9641494d.b4f00501
' Subject: This is a test
' MyCustomHeader: abc123
' Content-Type: text/plain; format=flowed
' 
' This is a plain-text body.
' ------=_NextPart_6e3_c655_9641494d.b4f00501
' Content-Transfer-Encoding: base64
' Content-Type: application/x-pkcs7-signature; name="smime.p7s"
' Content-Disposition: attachment; filename="smime.p7s"
' 
' MIID7AYJKoZIhvcNAQcCoIID3TCCA9kCAQExDzANBglghkgBZQMEAgEFADALBgkqhkiG9w0BBwGg
' ggJxMIICbTCCAhOgAwIBAgIJAJuS2kgOoyr+MAkGByqGSM49BAEwWzELMAkGA1UEBhMCQVUxEzAR
' BgNVBAgTClNvbWUtU3RhdGUxITAfBgNVBAoTGEludGVybmV0IFdpZGdpdHMgUHR5IEx0ZDEUMBIG
' A1UEAxMLZWNjMjU2LXRlc3QwHhcNMTYwODIzMTU0OTM5WhcNNDQwMTA4MTU0OTM5WjBbMQswCQYD
' VQQGEwJBVTETMBEGA1UECBMKU29tZS1TdGF0ZTEhMB8GA1UEChMYSW50ZXJuZXQgV2lkZ2l0cyBQ
' dHkgTHRkMRQwEgYDVQQDEwtlY2MyNTYtdGVzdDBZMBMGByqGSM49AgEGCCqGSM49AwEHA0IABARy
' Hd86A7+qQ4DlIfKynZaFGdGLpkU3GlQwqaVD6GIJg3QIDhaWEksYtZ9OWjNHn9a6+i/P9o5/NrdI
' SP0VWDWjgcAwgb0wHQYDVR0OBBYEFGmd2DfK4c3VBTVn8ebKH2BTmRicMIGNBgNVHSMEgYUwgYKA
' FGmd2DfK4c3VBTVn8ebKH2BTmRicoV+kXTBbMQswCQYDVQQGEwJBVTETMBEGA1UECBMKU29tZS1T
' dGF0ZTEhMB8GA1UEChMYSW50ZXJuZXQgV2lkZ2l0cyBQdHkgTHRkMRQwEgYDVQQDEwtlY2MyNTYt
' dGVzdIIJAJuS2kgOoyr+MAwGA1UdEwQFMAMBAf8wCQYHKoZIzj0EAQNJADBGAiEAhuiwGy0lZKtK
' LA13Ffc8AMTK7NsePPSfs0clXlZUR78CIQDXsJXpYsJ7tlTeockrK+6099sG/gGFTRPiQYU8juyf
' LzGCAT8wggE7AgEBMGgwWzELMAkGA1UEBhMCQVUxEzARBgNVBAgTClNvbWUtU3RhdGUxITAfBgNV
' BAoTGEludGVybmV0IFdpZGdpdHMgUHR5IEx0ZDEUMBIGA1UEAxMLZWNjMjU2LXRlc3QCCQCbktpI
' DqMq/jANBglghkgBZQMEAgEFAKBpMBgGCSqGSIb3DQEJAzELBgkqhkiG9w0BBwEwHAYJKoZIhvcN
' AQkFMQ8XDTIyMDUwODE0MzM1NFowLwYJKoZIhvcNAQkEMSIEIMvNpYuymLvF68aFFe+l3NEQTdkB
' 7T8U6/j+Y5FgDlIUMAoGCCqGSM49BAMCBEYwRAIgQ6migEn3Le9ciIVUP/qc2JZAJZWjpulJXY9Q
' IZJ3XK0CIGZwpLOgiv7ES8958hqT9a/q7aPc1xmkaZHtsat/k+Ki
' 
' ------=_NextPart_6e3_c655_9641494d.b4f00501--