(PowerShell) RSA Encrypt and Decrypt Credit Card Numbers

PowerShell sample code to RSA public-key encrypt and decrypt credit card numbers. The RSA key is loaded from an unencrypted PKCS8 file. Chilkat provides many ways of setting the key -- loading from both encrypted and unencrypted PEM, PKCS8, DER, PVK, etc. Keys may be loaded from files or in-memory representations. (The RSA component also provides the ability to generate RSA keys.)

Note: This example requires Chilkat v11.0.0 or greater.

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

$success = $false

# This example assumes the Chilkat API to have been previously unlocked.
# See Global Unlock Sample for sample code.

$rsa = New-Object Chilkat.Rsa

$privKey = New-Object Chilkat.PrivateKey

# Load an RSA private key from a file:
$success = $privKey.LoadAnyFormatFile("rsaPrivateKey.key","")
if ($success -eq $false) {
    $($privKey.LastErrorText)
    exit
}

# Get the public part of the private key.
$pubKey = New-Object Chilkat.PublicKey
$privKey.ToPublicKey($pubKey)

$success = $rsa.UsePublicKey($pubKey)
if ($success -eq $false) {
    $($rsa.LastErrorText)
    exit
}

# Encrypt a VISA credit card number:
# 1234-5678-0000-9999
$ccNumber = "1234567800009999"

$usePrivateKey = $false
$rsa.EncodingMode = "base64"
$encryptedStr = $rsa.EncryptStringENC($ccNumber,$usePrivateKey)
$("Encrypted:")
$($encryptedStr)

# Now decrypt:
$rsaDecryptor = New-Object Chilkat.Rsa

$rsaDecryptor.EncodingMode = "base64"
$rsaDecryptor.UsePrivateKey($privKey)

$usePrivateKey = $true
$decryptedStr = $rsaDecryptor.DecryptStringENC($encryptedStr,$usePrivateKey)

$("Decrypted:")
$($decryptedStr)

# Important: RSA encryption should only be used to encrypt small amounts of data.
# It is typically used for encrypting symmetric encryption
# keys such that a symmetric encryption algorithm, such as 
# AES is then used to encrypt/decrypt bulk data