(PowerShell) How to Parse a X.509 Certificate and Extract its Public Key

Demonstrates how to load an X.509 certificate and extract the public key. Chilkat supports many certificate encodings:

• DER (binary) encoded certificates (.crt/.cer)
• PEM (BASE64) encoded certificates (.pem)
• Load Certificates Directly from Windows Certificate Stores
• PFX/PKCS12 (.pfx/.p12)
• Java KeyStore (.jks)
• Cryptographic Message Syntax Standard - PKCS #7 Certificates (.P7B)

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[Reflection.Assembly]::LoadFile("C:\myAssemblies\ChilkatDotNet2.dll")

$cert = New-Object Chilkat.Cert

#  Load a DER (binary) encoded certificate.
#  To load from a .pem or .p7b, or any other file format that contains
#  just one certificate, call LoadFromFile in exactly the same way.
#  The LoadFromFile method automatically detects the format and loads the certificate.
$success = $cert.LoadFromFile("qa_data/certs/testCert.cer")
if ($success -eq $false) {
    $($cert.LastErrorText)
    exit
}

#  Get the public key:
$pubKey = $cert.ExportPublicKey()
if ($cert.LastMethodSuccess -ne $true) {
    $($cert.LastErrorText)
    exit
}

#  Examine the key type.
#  A PublicKey object can contain an RSA, ECC, or DSA public key.
#  The KeyType property will contain "rsa", "ecc", or "dsa".
$("key type = " + $pubKey.KeyType)