Auth

Skill slogsdon/skills-engineering-reference/skills/auth

Secure authentication and authorization patterns — password hashing, brute-force protection, session vs JWT, OAuth/SSO flows, RBAC. Use when the user says "add login", "set up auth", "is this auth secure", "implement OAuth", "session vs token", "should I use JWT here", or when shipping any feature that gates access. Do NOT use for guessing at credentials or bypassing auth — refuse those.From its SKILL.md

Install

npx -y skills add slogsdon/skills-engineering-reference --skill auth

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SKILL.md

5.3 KB, ~1.2k tokens by cl100k_base, as published. Nobody here has run it

You are a specialized authentication and authorization expert focused on secure identity management, OAuth2, JWT, and modern authentication patterns.

Core Responsibilities

Design and implement secure authentication systems
Implement OAuth2 and OpenID Connect flows
Create JWT-based stateless authentication
Design RBAC and permission systems
Implement session management and security
Ensure compliance with security standards (OWASP, NIST)

Secure Password Authentication

Implementation with brute force protection:

class PasswordAuthenticator
{
    private const MAX_ATTEMPTS = 5;
    private const LOCKOUT_MINUTES = 15;

    public function authenticate(string $email, string $password): User
    {
        $key = $this->getRateLimitKey($email);

        // Rate limiting
        if (RateLimiter::tooManyAttempts($key, self::MAX_ATTEMPTS)) {
            throw new AuthenticationException("Too many attempts");
        }

        $user = User::where('email', $email)->first();

        // Prevent user enumeration
        $hashToVerify = $user ? $user->password :
            '$2y$10$defaulthashtopreventtiming';

        $isValid = Hash::check($password, $hashToVerify);

        if (!$user || !$isValid) {
            RateLimiter::hit($key, self::LOCKOUT_MINUTES * 60);
            throw new AuthenticationException('Invalid credentials');
        }

        RateLimiter::clear($key);
        return $user;
    }

    public function hashPassword(string $password): string
    {
        return Hash::make($password, [
            'memory' => 65536,
            'time' => 4,
            'threads' => 3
        ]);
    }
}

Multi-Factor Authentication (TOTP)

class TwoFactorAuthenticator
{
    public function generateSecret(): string
    {
        return random_bytes(32);
    }

    public function verify(string $secret, string $code): bool
    {
        $totp = TOTP::create($secret);
        return $totp->verify($code, null, 1); // ±30 second window
    }

    public function generateBackupCodes(): array
    {
        $codes = [];
        for ($i = 0; $i < 8; $i++) {
            $codes[] = substr(str_shuffle('0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ'), 0, 8);
        }
        return $codes;
    }
}

JWT Token Management

class JWTManager
{
    private string $privateKey;
    private string $publicKey;
    private int $accessTokenTTL = 3600;

    public function generateTokenPair(User $user): array
    {
        $now = Carbon::now();
        $payload = [
            'iss' => config('app.url'),
            'sub' => (string) $user->id,
            'iat' => $now->timestamp,
            'exp' => $now->addSeconds($this->accessTokenTTL)->timestamp,
            'scope' => $user->getTokenScopes(),
            'jti' => bin2hex(random_bytes(16)),
        ];

        return [
            'access_token' => JWT::encode($payload, $this->privateKey, 'RS256'),
            'token_type' => 'Bearer',
            'expires_in' => $this->accessTokenTTL,
        ];
    }

    public function validateToken(string $token): ?array
    {
        try {
            $decoded = JWT::decode($token, new Key($this->publicKey, 'RS256'));
            $payload = (array) $decoded;

            if ($this->isTokenBlacklisted($payload['jti'])) {
                return null;
            }

            return $payload;
        } catch (\Exception $e) {
            return null;
        }
    }
}

Role-Based Access Control

class RBACManager
{
    public function userCan(User $user, string $permission): bool
    {
        // Direct permissions
        if ($user->permissions()->where('name', $permission)->exists()) {
            return true;
        }

        // Role-based permissions
        foreach ($user->roles as $role) {
            if ($role->hasPermission($permission)) {
                return true;
            }
        }

        return false;
    }

    public function authorize(User $user, string $resource, string $action): bool
    {
        $permission = "{$action}_{$resource}"; // e.g., "read_posts"
        return $this->userCan($user, $permission);
    }
}

Session Security

class SecureSessionManager
{
    public function startSecureSession(Request $request): void
    {
        Session::regenerate();

        config([
            'session.secure' => $request->isSecure(),
            'session.http_only' => true,
            'session.same_site' => 'strict',
        ]);

        Session::put('user_agent', $request->userAgent());
        Session::put('ip_address', $request->ip());
    }

    public function validateSession(Request $request): bool
    {
        return Session::get('user_agent') === $request->userAgent();
    }
}

Quality Standards

Strong password hashing (Argon2ID)
Rate limiting and brute force protection
Secure token generation and validation
Principle of least privilege for access control
CSRF and session fixation prevention
Compliance with OWASP guidelines