PowerShell

Add a Detached Signature (Header Placement Control)

Demonstrates the Chilkat Mime.AddDetachedSignature2 method, which creates the same multipart/signed structure as AddDetachedSignature, with a second argument controlling whether the existing message header fields are transferred to the new outer entity.

Note: The file paths are relative to the application's current working directory. Absolute paths may also be used. Supply the paths appropriate to your own environment.

Background: Signing wraps the content in a new outer multipart/signed, which raises the question of where the message-level headers (Subject, From, To) should live. This variant lets you choose: transfer them up to the outer entity so the signed message looks like a normal email, or leave them on the inner part. Transferring is typical for email; the finer control matters when the signed entity is embedded in a larger structure.

Chilkat PowerShell Downloads

Download Chilkat for PowerShell

PowerShell

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

$success = $false

$mime = New-Object Chilkat.Mime
$success = $mime.SetBodyFromPlainText("This message will be signed.")
if ($success -eq $false) {
    $($mime.LastErrorText)
    exit
}

#  Load the signing certificate (which must have access to its private key) from a PFX file.
#  The PFX password should come from a secure source rather than being hard-coded.
$pfxPassword = "myPfxPassword"
$cert = New-Object Chilkat.Cert
$success = $cert.LoadPfxFile("qa_data/signer.pfx",$pfxPassword)
if ($success -eq $false) {
    $($cert.LastErrorText)
    exit
}

#  AddDetachedSignature2 is the same as AddDetachedSignature, but the 2nd argument controls whether
#  the existing message header fields are transferred to the new outer multipart/signed entity.
$transferHeaderFields = $true
$success = $mime.AddDetachedSignature2($cert,$transferHeaderFields)
if ($success -eq $false) {
    $($mime.LastErrorText)
    exit
}

$success = $mime.SaveMime("qa_output/signed.eml")
if ($success -eq $false) {
    $($mime.LastErrorText)
    exit
}

$("Detached signature added (headers transferred).")