SteamTotpNet 1.0.0

SteamTotp

A .NET library for generating Steam-style TOTP authentication codes. Supports Steam Guard codes, mobile confirmation keys, device ID generation, and server time synchronization.

Installation

dotnet add package SteamTotp

Quick Start

using SteamTotp;

var service = new SteamTotpService();

// Generate a Steam Guard code from a hex secret
var code = service.GenerateAuthCodeHex("0123456789ABCDEF0123456789ABCDEF01234567");
Console.WriteLine(code); // e.g., "2W3R4"

API Reference

SteamTotpService

Main service for TOTP operations.

// Create with default dependencies
var service = new SteamTotpService();

// Create with custom dependencies (for testing)
var service = new SteamTotpService(customTimeProvider, customSecretDecoder);

Generate Authentication Code

// From hex secret
string code = service.GenerateAuthCodeHex("0123456789ABCDEF0123456789ABCDEF01234567");

// From base64 secret
string code = service.GenerateAuthCode("SGVsbG8gV29ybGQ=");

// From raw bytes
string code = service.GenerateAuthCode(secretBytes);

// With time offset (seconds ahead/behind Steam server)
string code = service.GenerateAuthCodeHex("0123456789ABCDEF...", offset: 10);

The offset parameter adjusts for clock drift between your server and Steam's servers. Use TimeOffsetService to calculate the correct offset.

Generate Confirmation Key

Generates keys needed for mobile trade confirmations.

// With tag: "conf" (confirm), "allow" (approve), "cancel" (reject), "details" (details)
string key = service.GenerateConfirmationKeyHex("FEDCBA9876543210...", timestamp, "conf");

// From base64 identity secret
string key = service.GenerateConfirmationKey(base64IdentitySecret, timestamp, "conf");

Get Current Time

long time = service.Time();
long timeWithOffset = service.Time(offset: 10);

TimeOffsetService

Synchronize with Steam's server time to ensure generated codes are valid.

var offsetService = new TimeOffsetService();
var result = await offsetService.GetTimeOffsetAsync();

Console.WriteLine($"Offset: {result.Offset}s");
Console.WriteLine($"Latency: {result.LatencyMs}ms");

Use the offset when generating codes:

var offsetService = new TimeOffsetService();
var result = await offsetService.GetTimeOffsetAsync();

var code = service.GenerateAuthCodeHex(secret, offset: (int)result.Offset);

DeviceIdGenerator

Generate standardized Android device IDs from SteamIDs.

var generator = new DeviceIdGenerator();

string deviceId = generator.GetDeviceId("STEAM_1:1:12345678");
// android:f1776fe6-a7ae-c9c3-e8f8-036c7edc1d31

// With custom salt
string deviceId = generator.GetDeviceId("STEAM_1:1:12345678", "my-salt");

SecretDecoder

Decode hex and base64 encoded secrets.

var decoder = new SecretDecoder();

byte[] fromHex = decoder.DecodeHex("0123456789ABCDEF");
byte[] fromBase64 = decoder.DecodeBase64("SGVsbG8gV29ybGQ=");

Architecture

The library follows SOLID principles with dependency injection support:

Testing

dotnet test

Requirements

• .NET Standard 2.0 compatible runtime

License

MIT