(PowerShell) RSAES-OAEP Encrypt String with AES-128 Content Encryption and SHA256

Encrypts a string using RSAES-OAEP with SHA256 and AES-128 content encryption to produce PKCS7 output (base64 encoded).

Note: This example requires Chilkat v9.5.0.67 or greater.

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Add-Type -Path "C:\chilkat\ChilkatDotNet47-9.5.0-x64\ChilkatDotNet47.dll"

# This example requires the Chilkat Crypt API to have been previously unlocked.
# See Unlock Chilkat Crypt for sample code.

# First build a string to be encrypted
$sb = New-Object Chilkat.StringBuilder
$i = 1
while ($i -lt 25) {
    $sb.AppendInt($i)
    $sb.Append(" the quick brown fox jumped over the lazy dog.`r`n")
    $i = $i + 1
}

$($sb.GetAsString())

# The string to be encrypted looks like this:

# 1 the quick brown fox jumped over the lazy dog.
# 2 the quick brown fox jumped over the lazy dog.
# 3 the quick brown fox jumped over the lazy dog.
# 4 the quick brown fox jumped over the lazy dog.
# 5 the quick brown fox jumped over the lazy dog.
# 6 the quick brown fox jumped over the lazy dog.
# ...

# Load a digital certificate. 
# We don't need the private key for encryption.
# Only the public key is needed (which is included in a certificate).
$cert = New-Object Chilkat.Cert
$success = $cert.LoadFromFile("qa_data/rsaes-oaep/cert.pem")
if ($success -ne $true) {
    $($cert.LastErrorText)
    exit
}

$crypt = New-Object Chilkat.Crypt2

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

# Indicate that we want PKI encryption (i.e. public-key infrastructure)
# to produce a CMS message (Cryptographic Message Syntax/PKCS7),
# that is be created with RSAES-OAEP padding, SHA256, and AES-128 for the
# bulk encryption.
$crypt.CryptAlgorithm = "pki"
$crypt.Pkcs7CryptAlg = "aes"
$crypt.KeyLength = 128
$crypt.OaepHash = "sha256"
$crypt.OaepPadding = $true

# Also, don't forget to be specific about the character encoding (byte representation) of the
# string to be encrypted.
$crypt.Charset = "utf-8"

# Now indicate that the PKCS7 output is to be returned in the base64 encoding.
$crypt.EncodingMode = "base64"

$base64Pkcs7 = $crypt.EncryptStringENC($sb.GetAsString())
if ($crypt.LastMethodSuccess -ne $true) {
    $($crypt.LastErrorText)
    exit
}

# Show the output
$($base64Pkcs7)

# This base64 can be copy-and-pasted into the form at http://lapo.it/asn1js/
# to verify that all the chosen algorithms were indeed used.

$("OK.")