(PowerShell) Add S/MIME Signature using PFX

Add a digital signature to a MIME message using the certificate + private key from a PFX file.

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.

$mime = New-Object Chilkat.Mime

# Load a PFX file into a certificate object.
$cert = New-Object Chilkat.Cert
$pfxFilepath = "pfxFiles/something.pfx"
$pfxPassword = "secret"
$success = $cert.LoadPfxFile($pfxFilepath,$pfxPassword)
if ($success -eq $false) {
    $($cert.LastErrorText)
    exit
}

$success = $mime.SetBodyFromPlainText("This is the plain-text MIME body.")

$mime.Charset = "utf-8"
$mime.Encoding = "quoted-printable"

# Sign the MIME (adds a PKCS7 detached signature)
$success = $mime.AddDetachedSignature($cert)
if ($success -eq $false) {
    $($mime.LastErrorText)
    exit
}

# Save the S/MIME to a file.
$success = $mime.SaveMime("/temp/signedMime.txt")
if ($success -eq $false) {
    $($mime.LastErrorText)
    exit
}

$("success!")