(PowerShell) CMS Sign Hash

Demonstrates how to use the SignHashENC method to sign a pre-computed hash. This method creates a CMS signature (PKCS7 detached signature).

This example requires Chilkat v9.5.0.90 or later.

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

# Create the hash to be signed...
$crypt.HashAlgorithm = "sha256"
$crypt.EncodingMode = "base64"
$crypt.Charset = "utf-8"
# Create the SHA256 hash of a string using the utf-8 byte representation.
# Return the hash as base64.
$base64Hash = $crypt.HashStringENC("This is the string to be hashed")

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

$crypt.SetSigningCert($cert)

# Sign the hash to create a base64 CMS signature (which does not contain the original data).
# We can get the signature in a single line of base64 by specifying "base64", or 
# we can get multi-line base64 by specifying "base64_mime".
$crypt.EncodingMode = "base64_mime"
$base64CmsSig = $crypt.SignHashENC($base64Hash,"sha256","base64")
if ($crypt.LastMethodSuccess -eq $false) {
    $($crypt.LastErrorText)
    exit
}

# Note: In the above call to SignHashENC, the encoding of the returned CMS signature is specified by the EncodingMode property.
# However, the encoding of the passed-in hash is indicated by the 3rd argument.

$("CMS Signature: " + $base64CmsSig)