(PureBasic) 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 PureBasic Module Download Chilkat PureBasic Module

IncludeFile "CkPublicKey.pb"
IncludeFile "CkCert.pb"

Procedure ChilkatExample()

    cert.i = CkCert::ckCreate()
    If cert.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    ; 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.i = CkCert::ckLoadFromFile(cert,"qa_data/certs/testCert.cer")
    If success = 0
        Debug CkCert::ckLastErrorText(cert)
        CkCert::ckDispose(cert)
        ProcedureReturn
    EndIf

    ; Get the public key:
    pubKey.i = CkCert::ckExportPublicKey(cert)
    If CkCert::ckLastMethodSuccess(cert) <> 1
        Debug CkCert::ckLastErrorText(cert)
        CkCert::ckDispose(cert)
        ProcedureReturn
    EndIf

    ; 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".
    Debug "key type = " + CkPublicKey::ckKeyType(pubKey)

    CkPublicKey::ckDispose(pubKey)



    CkCert::ckDispose(cert)


    ProcedureReturn
EndProcedure