// Create face authenticator and connect it to the device on port COM9
RealSenseID::FaceAuthenticator authenticator;
connect_status = authenticator.Connect({RealSenseID::SerialType::USB, "COM9"});

// Enroll a user
const char* user_id = "John";
MyEnrollClbk enroll_clbk;
auto status = authenticator.Enroll(enroll_clbk, user_id);

// Authenticate a user
MyAuthClbk auth_clbk;
status = authenticator.Authenticate(auth_clbk);

// Remove the user from device
success = authenticator.RemoveUser(user_id);

class MySigClbk : public RealSenseID::SignatureCallback
{
public:
    bool Sign(const unsigned char* buffer, const unsigned int buffer_len, unsigned char* out_sig) override
    {
      // Sign buffer with host ECDSA private key
    }

    bool Verify(const unsigned char* buffer, const unsigned int buffer_len, const unsigned char* sig,const unsigned int sign_len) override
    {
      // Verify buffer with device ECDSA public key
    }
};

MySigClbk sig_clbk;
RealSenseID::FaceAuthenticator authenticator {&sig_clbk};
Status connect_status = authenticator.Connect({RealSenseID::SerialType::USB, "COM9"});
authenticator.Disconnect();
char* hostPubKey = getHostPubKey(); // 64 bytes ECDSA public key of the host
char host_pubkey_signature[64];
if (!sig_clbk.Sign((unsigned char*)hostPubKey, 64, host_pubkey_signature))
{
    printf("Failed to sign host ECDSA key\n");
    return;
}
char device_pubkey[64]; // Save this key after getting it to use it for verification
Status pair_status = authenticator.Pair(host_pubkey, host_pubkey_signature, device_pubkey);

class MySigClbk : public RealSenseID::SignatureCallback
{
public:
    bool Sign(const unsigned char* buffer, const unsigned int buffer_len, unsigned char* out_sig) override
    {
      // Sign buffer with host ECDSA private key
    }

    bool Verify(const unsigned char* buffer, const unsigned int buffer_len, const unsigned char* sig,const unsigned int sign_len) override
    {
      // Verify buffer with device ECDSA public key
    }
};

MySigClbk sig_clbk;
RealSenseID::FaceAuthenticator authenticator {&sig_clbk};
Status connect_status = authenticator.Connect({RealSenseID::SerialType::USB, "COM9"});
authenticator.Disconnect();

Status pair_status = authenticator.Pair(host_pubkey, host_pubkey_signature, device_pubkey);

class MyEnrollClbk : public RealSenseID::EnrollmentCallback
{
public:
    void OnResult(const RealSenseID::EnrollStatus status) override
    {
        std::cout << "on_result: status: " << status << std::endl;
    }

    void OnProgress(const RealSenseID::FacePose pose) override
    {
        std::cout << "on_progress: pose: " << pose << std::endl;
    }

    void OnHint(const RealSenseID::EnrollStatus hint) override
    {
        std::cout << "on_hint: hint: " << hint << std::endl;
    }
};

const char* user_id = "John";
MyEnrollClbk enroll_clbk;
Status status = authenticator.Enroll(enroll_clbk, user_id);

class MyAuthClbk : public RealSenseID::AuthenticationCallback
{
public:
    // Called when authentication result is available.
    // If there are multiple faces it will be called for each face detected.
    void OnResult(const RealSenseID::AuthenticateStatus status, const char* user_id) override
    {
        if (status == RealSenseID::AuthenticateStatus::Success)
        {
            std::cout << "******* Authenticate success.  user_id: " << user_id << " *******" << std::endl;
        }
        else
        {
            std::cout << "on_result: status: " << status << std::endl;
        }
    }

    void OnHint(const RealSenseID::AuthenticateStatus hint) override
    {
        std::cout << "on_hint: hint: " << hint << std::endl;
    }
};

MyAuthClbk auth_clbk;
Status status = authenticator.Authenticate(auth_clbk);

class MyAuthClbk : public RealSenseID::AuthenticationCallback
{
public:
    // Called when result is available for a detected face.
    // If the status==AuthenticateStatus::Success then the user_id will point to c string of the authenenticated user id.
    void OnResult(const RealSenseID::AuthenticateStatus status, const char* user_id) override
    {
        if (status == RealSenseID::AuthenticateStatus::Success)
        {
            std::cout << "******* Authenticate success.  user_id: " << user_id << " *******" << std::endl;
        }
        else
        {
            std::cout << "on_result: status: " << status << std::endl;
        }
    }

    void OnHint(const RealSenseID::AuthenticateStatus hint) override
    {
        std::cout << "on_hint: hint: " << hint << std::endl;
    }

   
    // Called when faces are detected. Can be single or multiple faces.
    // The faces vector contains coord X(,y,h,w)of faces detected 
    // Coords are in full HD resolution (1920x1080):
    //   x,y: top left face rect
    //   w,h: width/height of the face rect
    //   Note: The `X` coords are flipped which means X==0 is most right, and X==1920 is most left.         
    // The timestamp argument is the timestamp in millis of the frame that the faces were found in.    
    void OnFaceDetected(const std::vector<RealSenseID::FaceRect>& faces, const unsigned int timestamp) override
    {
        _faces = faces;
    }
};

MyAuthClbk auth_clbk;
Status status = authenticator.AuthenticateLoop(auth_clbk);

struct RSID_API DeviceConfig
{
    /**
     * @enum CameraRotation
     * @brief Camera rotation.
     */
    enum class CameraRotation
    {
        Rotation_0_Deg = 0, // default
        Rotation_180_Deg = 1,
        Rotation_90_deg = 2,
        Rotation_270_deg = 3
    };

    /**
     * @enum SecurityLevel
     * @brief SecurityLevel to allow
     */
    enum class SecurityLevel
    {
        High = 0,   // high security, no mask support, all AS algo(s) will be activated
        Medium = 1, // default mode to support masks, only main AS algo will be activated.
    };
  
    /**
     * @enum AlgoFlow
     * @brief Algorithms which will be used during authentication
     */
    enum class AlgoFlow
    {
        All = 0,               // default
        FaceDetectionOnly = 1, // face detection only
        SpoofOnly = 2,         // spoof only
        RecognitionOnly = 3    // recognition only
    };

    /**
     * @enum FaceSelectionPolicy
     * @brief To run authentication on all (up to 5) detected faces vs single (closest) face
     */
    enum class FaceSelectionPolicy
    {
        Single = 0, // default, run authentication on closest face
        All = 1     // run authentication on all (up to 5) detected faces
    };

    enum class DumpMode
    {
        None = 0,
        CroppedFace = 1,
        FullFrame = 2,
    };

    CameraRotation camera_rotation = CameraRotation::Rotation_0_Deg;
    SecurityLevel security_level = SecurityLevel::Medium;
    AlgoFlow algo_flow = AlgoFlow::All;
    FaceSelectionPolicy face_selection_policy = FaceSelectionPolicy::Single;
    DumpMode dump_mode = DumpMode::None;
};

...
using namespace RealSenseID;
// config with default options except for the algo flow which is set to spoof only 
DeviceConfig device_config; 
device_config.algo_flow = AlgoFlow::SpoofOnly;
auto status = authenticator->SetDeviceConfig(device_config);

authenticator.Cancel();

bool success = authenticator.RemoveAll();

const char* user_id = "John";
bool success = authenticator.RemoveUser(user_id);

RealSenseID::DeviceController deviceController;
Status connect_status = deviceController.Connect({RealSenseID::SerialType::USB, "COM9"});
deviceController.Disconnect();

bool success = deviceController.Reboot();

/**
 * Preview modes
 */
enum class PreviewMode
{
    MJPEG_1080P = 0, // default
    MJPEG_720P = 1,
    RAW10_1080P = 2,
};

/**
 * Preview configuration
 */
struct RSID_API PreviewConfig
{
    int cameraNumber = -1; // attempt to auto detect by default
    PreviewMode previewMode = PreviewMode::MJPEG_1080P; // RAW10 requires custom fw support
    bool portraitMode = true; 
};

class PreviewRender : public RealSenseID::PreviewImageReadyCallback
{
public:
	void OnPreviewImageReady(const Image image)
	{
		// Callback will be used to provide RGB preview image (for RAW10_1080P PreviewMode - raw converted to RGB).
	}

    	void OnSnapshotImageReady(const Image image) // Not mandatory. To enable it, see Device Configuration API.
	{
		// Callback will be used to provide images destined to be dumped (cropped/full). See DeviceConfig::DumpMode attribute.
		// Raw formatted images will be raised by this function.
	}
};

PreviewRender image_clbk;
Preview preview;
bool success = preview.StartPreview(image_clbk);

bool success = preview.PausePreview();

bool success = preview.ResumePreview();

bool success = preview.StopPreview();

// extract faceprints using authentication flow
class FaceprintsAuthClbk : public RealSenseID::AuthFaceprintsExtractionCallback
{
public:
    void OnResult(const RealSenseID::AuthenticateStatus status, const Faceprints* faceprints) override
    {
        std::cout << "result: " << status << std::endl;
        s_extraction_status = status;
        // if status was success pass '_faceprints' to user 
    }

    void OnHint(const RealSenseID::AuthenticateStatus hint) override
    {
        std::cout << "hint: " << hint << std::endl;
    }
};

FaceprintsAuthClbk clbk;
auto status = authenticator->ExtractFaceprintsForAuth(clbk);

// extract faceprints using enrollment flow
class MyEnrollServerClbk : public RealSenseID::EnrollmentCallback
{
    const char* _user_id = nullptr;

public:
    explicit MyEnrollServerClbk(const char* user_id) : _user_id {user_id}
    {        
    }

    void OnResult(const RealSenseID::EnrollStatus status, const Faceprints* faceprints) override
    {
        std::cout << "result: " << status << "for user: " << _user_id << std::endl;
        s_extraction_status = status;    
        // if status was success pass '_faceprints' to user            
    }

    void OnProgress(const RealSenseID::FacePose pose) override
    {
        std::cout << "pose: " << pose << std::endl;
    }

    void OnHint(const RealSenseID::EnrollStatus hint) override
    {
        std::cout << "hint: " << hint << std::endl;
    }
};

MyEnrollServerClbk enroll_clbk {user_id.c_str()};
auto status = authenticator->ExtractFaceprintsForEnroll(enroll_clbk);

// extract faceprints in a loop using authentication flow
class AuthLoopExtrClbk : public RealSenseID::AuthFaceprintsExtractionCallback
{    
public:
    void OnResult(const RealSenseID::AuthenticateStatus status, const Faceprints* faceprints) override
    {        
        std::cout << "result: " << status << std::endl;
        s_extraction_status = status;
        // if status was success pass '_faceprints' to user 
    }

    void OnHint(const RealSenseID::AuthenticateStatus hint) override
    {
        std::cout << "hint: " << hint << std::endl;
    }
};

AuthLoopExtrClbk clbk;
auto status = authenticator->ExtractFaceprintsForAuthLoop(clbk);

// match extracted faceprints to the ones in the user-managed database
for (auto& db_item : db)
{
    auto match_result = authenticator->MatchFaceprints(scanned_faceprints, db_item.faceprints, updated_faceprints);    
    if (match_result.success)
    {
        std::cout << "Match succeeded with user id: " << db_item.id << std::endl;
        break;
    }
}