(PowerShell) Decrypt a .p7m File (using a PFX)

PowerShell sample code showing how to decrypt a .p7m using a .p12 / .pfx certificate w/ private key.

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.

$crypt = New-Object Chilkat.Crypt2

# Use a digital certificate and private key from a PFX file (.pfx or .p12).
$pfxPath = "myCertAndKey.pfx"
$pfxPassword = "test123"

$success = $crypt.AddPfxSourceFile($pfxPath,$pfxPassword)
if ($success -ne $true) {
    $($crypt.LastErrorText)
    exit
}

# Set the  outPath to whatever is appropriate.
# If you are decrypting a PDF, your output might be "out.pdf"...
$inPath = "smime.p7m"
$outPath = "original.txt"

# Indicate that we're doing public key decryption (i.e. PKCS7)
$crypt.CryptAlgorithm = "pki"

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

$("Success.")