(C#) HTTPS Mutual Authentication using Smartcard or Token

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Explains how to do HTTP TLS mutual authentication using an HSM (Smartcard or USB Token).

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Chilkat.Http http = new Chilkat.Http();

// To do HTTPS mutual authentication where the certificate and private key are stored
// on a smartcard or token, first load the Chilkat certificate object from the smartcard/token,
// and then pass the certificate object to the Http object's SetSslClientCert method.

// Doing HTTP mutual authentication is the same regardless of the source of the cert + private key.
// The steps are to first load the certificate from the source, then pass the cert object to the HTTP object.
// Chilkat provides methods for loading the certificate from a variety of sources, such as smartcards, tokens,
// .pfx/.p12 files, Windows registry-based certificate stores, PEM files, or other file formats.
Chilkat.Cert cert = new Chilkat.Cert();

// The easiest way to load a certificate from an HSM is to call cert.LoadFromSmartcard with 
// an empty string argument.  Chilkat will detect the HSM and will choose the most appropriate
// underlying means for accessing and loading the default certificate + key from the HSM.
// The underlying means could be PKCS11, ScMinidriver, or MSCNG, depending on the HSM what it
// supports.

// For example:
// If you know the smart card PIN, it's good to set it prior to loading from the smartcard/USB token.
cert.SmartCardPin = "12345678";

// To let Chilkat discover what smartcard or token is connected, pass an empty string to LoadFromSmartcard.
// When testing in this way, it's best to have only a single smartcard or token connected to the system.
bool success = cert.LoadFromSmartcard("");
if (success == false) {
    Debug.WriteLine(cert.LastErrorText);
    Debug.WriteLine("Certificate not loaded.");
    return;
}

// If there are multiple certificates stored on the smartcard/token, then 
// you can be more specific.  See these examples:

// Load a Certificate from an HSM by Common Name
// Load a Certificate from an HSM by Serial Number

// It may be that you need to code at a lower level with a specific
// supported interface, such as PKCS11.
// See these examples:

// Use PKCS11 to Find a Specific Certificate
// Use PKCS11 to Find a Certificate with a Specified Key Usage

// Once you have the desired certificate, pass it to SetSslClientCert.
// Set the certificate to be used for mutual TLS authentication
// (i.e. sets the client-side certificate for two-way TLS authentication)
success = http.SetSslClientCert(cert);
if (success != true) {
    Debug.WriteLine(http.LastErrorText);
    return;
}

// At this point, the HTTP object instance is setup with the client-side cert, and any SSL/TLS
// connection will automatically use it if the server demands a client-side cert.