(PowerShell) Extract PKCS7 from MIME and Decrypt

Extracts the base64-encoded PKCS7 body of a MIME message to a file, and then decrypts using Chilkat Crypt2.

Chilkat .NET Downloads Chilkat .NET Assemblies

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.

$mime = New-Object Chilkat.Mime

$success = $mime.LoadMimeFile("c:/aaworkarea/EmailInBytes.txt")
if ($success -ne $true) {
    $($mime.LastErrorText)
    exit
}

$success = $mime.SaveBody("c:/aaworkarea/smime.p7m")
if ($success -ne $true) {
    $($mime.LastErrorText)
    exit
}

$crypt = New-Object Chilkat.Crypt2

$success = $crypt.AddPfxSourceFile("c:/aaworkarea/my.pfx","pfxPassword")
if ($success -eq $false) {
    $($crypt.LastErrorText)
    exit
}

# Indicate the public-key (PKCS7) encryption/decryption should be used:
$crypt.CryptAlgorithm = "pki"

$inPath = "c:/aaworkarea/smime.p7m"
$outPath = "c:/aaworkarea/decrypted.dat"

$success = $crypt.CkDecryptFile($inPath,$outPath)
if ($success -eq $false) {
    $($crypt.LastErrorText)
    exit
}

$("Success.")