(PowerShell) Create PKCS7 (CMS) EnvelopedData

Encrypt some data to a recipient by creating a PKCS7 (CMS) EnvelopedData structure. The data will be encrypted using a symmetric content-encryption algorithm (e.g., AES), and the randomly generated symmetric key will be encrypted using the recipient’s RSA public key extracted from their X.509 certificate.

Chilkat .NET Downloads Chilkat .NET Assemblies

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

$crypt = New-Object Chilkat.Crypt2

# Specify the encryption to be used.
# "pki" indicates "Public Key Infrastructure" and will create a PKCS7 encrypted (enveloped-data) message.
$crypt.CryptAlgorithm = "pki"
$crypt.Pkcs7CryptAlg = "aes"
$crypt.KeyLength = 256
$crypt.OaepHash = "sha256"
$crypt.OaepPadding = $true

$cert = New-Object Chilkat.Cert

# Use a certificate found in the Windows certificate store.
$success = $cert.LoadByCommonName("My Certificate")
if ($success -ne $true) {
    $($cert.LastErrorText)
    exit
}

# Tell the crypt object to use the certificate.
$crypt.SetEncryptCert($cert)

$toBeEncrypted = "This string is to be encrypted."

# Get the result in multi-line BASE64 MIME format.
$crypt.EncodingMode = "base64_mime"
$crypt.Charset = "utf-8"

$result = $crypt.EncryptStringENC($toBeEncrypted)
if ($success -ne $true) {
    $($crypt.LastErrorText)
    exit
}

# -------------------------------------------------------------------------
# See the following example to decrypt what was created in this example
# Decrypt PKCS7 (CMS) EnvelopedData
# -------------------------------------------------------------------------

$($result)

# Sample output:

# MIICSgYJKoZIhvcNAQcDoIICOzCCAjcCAQAxggHiMIIB3gIBADCBljCBgTELMAkGA1UEBhMCSVQx
# EDAOBgNVBAgMB0JlcmdhbW8xGTAXBgNVBAcMEFBvbnRlIFNhbiBQaWV0cm8xFzAVBgNVBAoMDkFj
# dGFsaXMgUy5wLkEuMSwwKgYDVQQDDCNBY3RhbGlzIENsaWVudCBBdXRoZW50aWNhdGlvbiBDQSBH
# MwIQPCWvkSv8oQ7xRmEHJ6TzEDA8BgkqhkiG9w0BAQcwL6APMA0GCWCGSAFlAwQCAQUAoRwwGgYJ
# KoZIhvcNAQEIMA0GCWCGSAFlAwQCAQUABIIBAKqHAPQNSsQoX7B2NH7QyEOWQRsSVs8oCHXmy8f4
# MVZD2er3bvYUCIomxpwbLEAl14qjUIMynahooYGgqip7+4FqL301G+BVjZVfEhHWj+VI1dAWnWuL
# VHlvc/pbQNBWqV8rKVJsNIsuAZkdj4WSwLVKxYkYX43B8fh/g71XN2DTJu7Z/824v48KBmgpQBOT
# 2q7IcDGxNPAFN2p6eavIVGn2LvhEbf/Fszyj+GR5tMcnQP1BOLJ3s3JzUBbvj8hcZrF1Vhl9HnTU
# YQx8G/KdW1mR+Wlhl3BWoK0LYKRTbnTx2BXOs0CY1SXOAdhKr01ZYjA+xW4nGzY0lfXS9QZjh9gw
# TAYJKoZIhvcNAQcBMB0GCWCGSAFlAwQBKgQQw0xTbfmnt0zjWHo5SaQIp4AgxTVY9E/Ncqy6t+RM
# 8y4c3Av62/wB8IpPUEmtM2OeuZo=