(PowerShell) Sign a Byte Array to Create an Opaque Signature in a Byte Array

Signs data contained in a byte array to produce an opaque signature (also in a byte array). An opaque signature is a PKCS7 signature (also known as CAdES) that embeds the signed data. Also shows how to verify the signature and extract the original data.

Chilkat .NET Downloads Chilkat .NET Assemblies

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

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

$cert = New-Object Chilkat.Cert
$success = $cert.LoadPfxFile("qa_data/pfx/cert_test123.pfx","test123")
if ($success -eq $false) {
    $($cert.LastErrorText)
    exit
}

$fac = New-Object Chilkat.FileAccess

$fileBytes = $fac.ReadEntireFile("qa_data/pdf/sample.pdf")
if ($fac.LastMethodSuccess -ne $true) {
    $($fac.LastErrorText)
    exit
}

$crypt = New-Object Chilkat.Crypt2

$success = $crypt.SetSigningCert($cert)

# We can sign any type of file.

$sigBytes = $crypt.OpaqueSignBytes($fileBytes)
if ($crypt.LastMethodSuccess -ne $true) {
    $($crypt.LastErrorText)
    exit
}

$success = $fac.WriteEntireFile("qa_output/sample.pdf.p7m",$sigBytes)
if ($fac.LastMethodSuccess -ne $true) {
    $($fac.LastErrorText)
    exit
}

# We can verify the opaque signature and extract the original data like this

$originalData = $crypt.OpaqueVerifyBytes($sigBytes)
if ($crypt.LastMethodSuccess -ne $true) {
    $($crypt.LastErrorText)
    exit
}

$success = $fac.WriteEntireFile("qa_output/sample.pdf",$originalData)
if ($fac.LastMethodSuccess -ne $true) {
    $($fac.LastErrorText)
    exit
}

$("Signature is verified and the original data was extracted.")