(PowerShell) 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.

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Add-Type -Path "C:\chilkat\ChilkatDotNet47-9.5.0-x64\ChilkatDotNet47.dll"

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

$crypt = New-Object Chilkat.Crypt2
$cert = New-Object Chilkat.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 -eq $false) {
    $($cert.LastErrorText)
    exit
}

$success = $crypt.SetSigningCert($cert)
if ($success -eq $false) {
    $($crypt.LastErrorText)
    exit
}

# 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.)
$bd = New-Object Chilkat.BinData
$success = $bd.LoadFile("qa_data/p7s/cosign/sample.pdf.p7s")
if ($success -eq $false) {
    $("Failed to load pdf.p7s input file.")
    exit
}

# bd2 will contain the co-signed result.
$bd2 = New-Object Chilkat.BinData
$success = $crypt.CoSign($bd,$cert,$bd2)
if ($success -eq $false) {
    $($crypt.LastErrorText)
    exit
}

$success = $bd.WriteFile("qa_output/cosigned.pdf.p7s")
if ($success -eq $false) {
    $("Failed to save pdf.p7s output file.")
    exit
}

$("Success!")