diff --git a/auth.php b/auth.php
new file mode 100644
index 0000000..37a6ebd
--- /dev/null
+++ b/auth.php
@@ -0,0 +1,62 @@
+<?php
+const MVLOG_AUTH_CONFIG = '/etc/mvlog/auth.php';
+
+function mvlog_session_start(): void {
+    if (session_status() === PHP_SESSION_ACTIVE) return;
+    $secure = (!empty($_SERVER['HTTPS']) && $_SERVER['HTTPS'] !== 'off');
+    session_name('MVLOGSESSID');
+    session_set_cookie_params([
+        'lifetime' => 0,
+        'path' => '/mvlog',
+        'secure' => $secure,
+        'httponly' => true,
+        'samesite' => 'Lax',
+    ]);
+    session_start();
+}
+
+function mvlog_auth_config(): array {
+    if (!is_file(MVLOG_AUTH_CONFIG)) return ['users' => []];
+    $config = require MVLOG_AUTH_CONFIG;
+    return is_array($config) ? $config : ['users' => []];
+}
+
+function mvlog_login(string $user, string $password): bool {
+    mvlog_session_start();
+    $users = mvlog_auth_config()['users'] ?? [];
+    $hash = is_array($users) ? ($users[$user] ?? null) : null;
+    if (!is_string($hash) || !password_verify($password, $hash)) return false;
+    session_regenerate_id(true);
+    $_SESSION['mvlog_user'] = $user;
+    $_SESSION['mvlog_login_at'] = time();
+    return true;
+}
+
+function mvlog_current_user(): ?string {
+    mvlog_session_start();
+    return isset($_SESSION['mvlog_user']) && is_string($_SESSION['mvlog_user']) ? $_SESSION['mvlog_user'] : null;
+}
+
+function mvlog_require_login(): void {
+    if (mvlog_current_user() !== null) return;
+    $next = $_SERVER['REQUEST_URI'] ?? '/mvlog/new.php';
+    header('Location: login.php?next=' . rawurlencode($next));
+    exit;
+}
+
+function mvlog_logout(): void {
+    mvlog_session_start();
+    $_SESSION = [];
+    if (ini_get('session.use_cookies')) {
+        $params = session_get_cookie_params();
+        setcookie(session_name(), '', time() - 42000, $params['path'], $params['domain'] ?? '', $params['secure'], $params['httponly']);
+    }
+    session_destroy();
+}
+
+function mvlog_safe_next(string $next): string {
+    if ($next === '' || str_contains($next, "\n") || str_contains($next, "\r")) return 'new.php';
+    $parts = parse_url($next);
+    if ($parts === false || isset($parts['scheme']) || isset($parts['host'])) return 'new.php';
+    return $next;
+}
diff --git a/login.php b/login.php
new file mode 100644
index 0000000..4b69860
--- /dev/null
+++ b/login.php
@@ -0,0 +1,23 @@
+<?php
+require __DIR__ . '/auth.php';
+$err = '';
+$next = mvlog_safe_next((string)($_GET['next'] ?? $_POST['next'] ?? 'new.php'));
+if (mvlog_current_user() !== null) {
+    header('Location: ' . $next);
+    exit;
+}
+if ($_SERVER['REQUEST_METHOD'] === 'POST') {
+    $user = trim((string)($_POST['user'] ?? ''));
+    $pass = (string)($_POST['password'] ?? '');
+    if (mvlog_login($user, $pass)) {
+        header('Location: ' . $next);
+        exit;
+    }
+    $err = 'Invalid username or password.';
+}
+function h($s){ return htmlspecialchars((string)$s, ENT_QUOTES, 'UTF-8'); }
+?>
+<!doctype html><html><head><meta charset="utf-8"><meta name="viewport" content="width=device-width,initial-scale=1"><title>MVLog Login</title><link rel="stylesheet" href="style.css"></head><body>
+<header class="site-header"><a class="brand" href="index.php"><h1>MVLog Admin</h1><p>Bubulescu.Org</p></a></header>
+<main><section><h2>Log in</h2><?php if($err): ?><div class="err"><?=h($err)?></div><?php endif; ?><form method="post" autocomplete="on"><input type="hidden" name="next" value="<?=h($next)?>"><label>Username<input name="user" autocomplete="username" required autofocus></label><label>Password<input type="password" name="password" autocomplete="current-password" required></label><button type="submit">Log in</button></form></section></main>
+</body></html>
diff --git a/logout.php b/logout.php
index 4069d07..920bb0b 100644
--- a/logout.php
+++ b/logout.php
@@ -1,12 +1,6 @@
 <?php
-$secure = (!empty($_SERVER['HTTPS']) && $_SERVER['HTTPS'] !== 'off');
-setcookie('mvlog_realm', bin2hex(random_bytes(8)), [
-    'expires' => time() + 31536000,
-    'path' => '/mvlog',
-    'secure' => $secure,
-    'httponly' => true,
-    'samesite' => 'Lax',
-]);
+require __DIR__ . '/auth.php';
+mvlog_logout();
 header('Cache-Control: no-store, no-cache, must-revalidate, max-age=0');
 header('Location: index.php');
 exit;
diff --git a/new.php b/new.php
index b66fd05..92932a8 100644
--- a/new.php
+++ b/new.php
@@ -1,4 +1,6 @@
 <?php
+require __DIR__ . '/auth.php';
+mvlog_require_login();
 $config = require __DIR__ . "/config.php";
 foreach (["videos_dir", "thumbs_dir", "uploads_dir"] as $d) if (!is_dir($config[$d])) mkdir($config[$d], 0775, true);
 function h($s){ return htmlspecialchars((string)$s, ENT_QUOTES, "UTF-8"); }
