B4X

CoSign PKCS7/CMS Signed Data

See more Digital Signatures Examples

Demonstrates how to add a 2nd signature to a CMS SignedData. This is to add an additional signature, SignerInfo and certificate(s) to an existing CMS signed data.

In this example, we cosign an existing pdf.p7s

Note: The CoSign method is added in Chilkat v9.5.0.89.

B4X

Dim success As Boolean = False

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

Dim crypt As ChilkatCrypt2
crypt.Initialize("crypt")
Dim cert As ChilkatCert
cert.Initialize("cert")

'  If loading from a smart card, set the smartcard PIN.
cert.SmartCardPin = "0000"

'  Load a certificate in some way, such as from a smart card.
'  Chilkat provides other methods to load from a .pfx, .pem, or from the Windows certificate stores..
success = cert.LoadFromSmartcard("")
If success = False Then
    Log(cert.LastErrorText)
    Return
End If


success = crypt.SetSigningCert(cert)
If success = False Then
    Log(crypt.LastErrorText)
    Return
End If


'  Load the file to be co-signed.
'  NOTE:  This is to cosign a PDF file contained within a CMS (PKCS7) message.
'  (In other words, the PDF is contained within the CMS SignedData, rather than the other way around
'  where a CMS signature is contained within a PDF.  Use Chilkat's PDF class to sign a PDF, which is
'  to embed a CMS signature within the PDF.)
Dim bd As ChilkatBinData
bd.Initialize
success = bd.LoadFile("qa_data/p7s/cosign/sample.pdf.p7s")
If success = False Then
    Log("Failed to load pdf.p7s input file.")
    Return
End If


'  bd2 will contain the co-signed result.
Dim bd2 As ChilkatBinData
bd2.Initialize
success = crypt.CoSign(bd, cert, bd2)
If success = False Then
    Log(crypt.LastErrorText)
    Return
End If


success = bd.WriteFile("qa_output/cosigned.pdf.p7s")
If success = False Then
    Log("Failed to save pdf.p7s output file.")
    Return
End If


Log("Success!")