AuthForge C# SDK

Official C# SDK for AuthForge — credit-based license key authentication with Ed25519-verified responses.

Dependencies: BouncyCastle.Cryptography for Ed25519 verification. Targets .NET 6+.

Installation

The package is AuthForge on NuGet.

dotnet add package AuthForge

Alternative: copy AuthForgeClient.cs into your solution if you need a source-only vendored layout (you still need the same NuGet dependencies declared in your project).

Quick Start

using AuthForge;

var client = new AuthForgeClient(
    appId: "YOUR_APP_ID",           // from your AuthForge dashboard
    appSecret: "YOUR_APP_SECRET",   // from your AuthForge dashboard
    publicKey: "YOUR_PUBLIC_KEY",   // base64 Ed25519 public key from dashboard
    heartbeatMode: "SERVER"         // "SERVER" or "LOCAL"
);

Console.Write("Enter license key: ");
var key = Console.ReadLine() ?? "";

if (client.Login(key))
{
    Console.WriteLine("Authenticated!");
    // Your app logic here — heartbeats run automatically in the background
}
else
{
    Console.WriteLine("Invalid license key.");
    Environment.Exit(1);
}

Configuration

Parameter	Type	Default	Description
appId	string	required	Your application ID from the AuthForge dashboard
appSecret	string	required	Your application secret from the AuthForge dashboard
publicKey	string	required	App Ed25519 public key (base64) from dashboard
heartbeatMode	string	required	"SERVER" or "LOCAL" (see below)
heartbeatInterval	int	900	Seconds between heartbeat checks (any value ≥ 1; default 15 min)
apiBaseUrl	string	https://auth.authforge.cc	API endpoint
onFailure	Action<string, Exception?>	null	Callback on auth failure
requestTimeout	int	15	HTTP request timeout in seconds
ttlSeconds	int?	null (server default: 86400)	Requested session token lifetime. Server clamps to [3600, 604800]; preserved across heartbeat refreshes.
hwidOverride	string?	null	Optional custom hardware/subject identifier. When set to a non-empty value, the SDK uses it instead of machine fingerprinting.

Identity-based binding example (Telegram/Discord)

var client = new AuthForgeClient(
    appId: "YOUR_APP_ID",
    appSecret: "YOUR_APP_SECRET",
    publicKey: "YOUR_PUBLIC_KEY",
    heartbeatMode: "SERVER",
    hwidOverride: $"tg:{telegramUserId}" // or $"discord:{discordUserId}"
);

Billing

• One Login() or ValidateLicense() call = 1 credit (one /auth/validate debit each).
• 10 heartbeats on the same session = 1 credit (debited on every 10th successful heartbeat).

Any heartbeat interval is safe economically: a desktop app running 6h/day at a 15-minute interval burns ~3–4 credits/day; a server app running 24/7 at a 1-minute interval burns ~145 credits/day. Choose your interval based on how quickly you need revocations to propagate (they always land on the next heartbeat).

Methods

Method	Returns	Description
Login(string licenseKey)	bool	Validates key and stores signed session (sessionToken, expiresIn, appVariables, licenseVariables)
ValidateLicense(string licenseKey)	ValidateLicenseResult	Same /auth/validate + signatures as Login; does not update client session or start heartbeats; never calls onFailure or Environment.Exit
SelfBan(...)	Dictionary<string, object?>	Requests /auth/selfban to blacklist HWID/IP and optionally revoke (session-authenticated only)
Logout()	void	Stops heartbeat and clears all session/auth state
IsAuthenticated()	bool	True when an active authenticated session exists
GetSessionData()	Dictionary<string, object?>?	Full decoded payload map
GetAppVariables()	Dictionary<string, object?>?	App-scoped variables map
GetLicenseVariables()	Dictionary<string, object?>?	License-scoped variables map

Heartbeat Modes

SERVER — The SDK calls /auth/heartbeat every heartbeatInterval seconds with a fresh nonce, verifies signature + nonce, and triggers failure on invalid session state.

LOCAL — No network calls. The SDK re-verifies stored signature state and checks expiry timestamp locally. If expired, it triggers failure with session_expired.

Failure Handling

If authentication fails, the SDK calls your onFailure callback if one is provided. If no callback is set, the SDK calls Environment.Exit(1) to terminate the process. This is intentional — it prevents your app from running without a valid license.

ValidateLicense() returns a result object instead; it does not invoke onFailure or exit for validate/network failures.

Recognized server errors: invalid_app, invalid_key, expired, revoked, hwid_mismatch, no_credits, blocked, rate_limited, replay_detected, app_disabled, session_expired, revoke_requires_session, bad_request

Request retries are automatic inside the internal HTTP layer:

• rate_limited: retry after 2s, then 5s (max 3 attempts total)
• network failure: retry once after 2s
• every retry regenerates a fresh nonce

var client = new AuthForgeClient(
    appId: "YOUR_APP_ID",
    appSecret: "YOUR_APP_SECRET",
    publicKey: "YOUR_PUBLIC_KEY",
    heartbeatMode: "SERVER",
    onFailure: (reason, exception) =>
    {
        Console.WriteLine($"Auth failed: {reason}");
        if (exception != null)
            Console.WriteLine($"Details: {exception.Message}");
        Environment.Exit(1);
    }
);

Self-ban (tamper response)

Use SelfBan(...) when anti-tamper checks trigger:

// Post-session (authenticated): defaults to revoke + HWID/IP blacklist.
client.SelfBan();

// Pre-session: pass licenseKey, SDK automatically disables revokeLicense.
client.SelfBan(licenseKey: "AF-XXXX-XXXX-XXXX");

// Custom flags:
client.SelfBan(
    blacklistHwid: true,
    blacklistIp: true,
    revokeLicense: false
);

SelfBan(...) auto-selects request mode:

• Uses post-session mode when a session token is available (sessionToken argument or current SDK session).
• Falls back to pre-session mode with licenseKey + nonce + app secret.
• In pre-session mode, revoke is forced off client-side to avoid unsafe key revocations.

How It Works

1. Login — Uses hwidOverride if provided; otherwise collects a hardware fingerprint (MAC, CPU, disk serial). It then generates a random nonce and sends everything to the AuthForge API. The server validates the license key, binds the HWID, deducts a credit, and returns a signed payload. The SDK verifies the Ed25519 signature and nonce to prevent replay attacks.

2. Heartbeat — A background thread checks in at the configured interval. In SERVER mode, it sends a fresh nonce and verifies the response. In LOCAL mode, it re-verifies the stored signature and checks expiry without network calls.

3. Crypto — Both /validate and /heartbeat responses are signed by AuthForge with your app's Ed25519 private key. The SDK verifies every signed payload using your configured publicKey and rejects tampered responses.

Test Vectors

The test_vectors.json file is shared across all SDKs and validates cross-language Ed25519 verification behavior.

Requirements

• .NET 6+
• NuGet package: BouncyCastle.Cryptography

License

MIT