(Ruby) 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)

Chilkat Ruby Downloads install from rubygems.org gem install chilkat or download... Ruby Library for Windows, MacOS, Linux, Alpine Linux

require 'chilkat'

cert = Chilkat::CkCert.new()

# 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 == false)
    print cert.lastErrorText() + "\n";
    exit
end

# Get the public key:
# pubKey is a CkPublicKey
pubKey = cert.ExportPublicKey()
if (cert.get_LastMethodSuccess() != true)
    print cert.lastErrorText() + "\n";
    exit
end

# 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".
print "key type = " + pubKey.keyType() + "\n";