diff --git a/.gitignore b/.gitignore
index f3be5cb..3d060ad 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,3 +1,4 @@
 /.next/
 /node_modules/
-/.idea
\ No newline at end of file
+/.idea
+check-syntax.sh
diff --git a/js/CommonComponents.js b/js/CommonComponents.js
index 87791dd..b32d412 100644
--- a/js/CommonComponents.js
+++ b/js/CommonComponents.js
@@ -2,20 +2,27 @@ import {
     Badge,
     Button,
     ButtonGroup,
+    Card,
+    CardBody,
+    Container,
     Collapse,
+    Form,
+    FormGroup,
     Nav,
     Navbar,
     NavbarBrand,
     NavbarToggler,
     NavItem,
-    NavLink
+    NavLink,
+    Input,
+    Label
 } from 'reactstrap';
 
 import { connect } from 'react-redux';
 
 import React from 'react';
 
-import { logout } from './api';
+import { login, logout } from './api';
 
 export function BigImage(props) {
     return (
@@ -95,7 +102,6 @@ class InvisibleLoginLogoutButtons extends React.Component {
             );
         }
     }
-
 }
 
 const mapStateToLoginLogoutButtonProperties = (state) => {
@@ -124,3 +130,153 @@ export function Footer() {
         </footer>
     );
 }
+
+/**
+ * This component works just like a switch statement, although the conditions of the first items
+ * are checked first, and the first component with a condition that is true will be shown.
+ * 
+ * For single conditions and options any kind of component can be taken, while the Option-component
+ * is dedicated for this job. The only important thing is that this component has to have a condition property.
+ *
+ * You should also give a default option with a condition that always evaluates to true.
+ *
+ * A quick example would be some content that is only to be shown when the user is logged in:
+ *
+ * function SomeRestrictedContent(props) {
+ *     const { isSignedIn } = props;
+ *     
+ *     return (
+ *         <UserRestrictor>
+ *             <Option condition={isSignedIn}>
+ *                 < The restricted content >
+ *             </Option>
+ *             <Option condition={true}>
+ *                 < Some default content; in this case some kind of login >
+ *             </Option>
+ *         </UserRestrictor>
+ *     );
+ * }
+ *
+ * In the example you'll have to note that the default option is at the bottom of all the options
+ * since it would always be taken otherwise (the options' conditions are checked from top to bottom)
+ */
+export class UserRestrictor extends React.Component {
+
+    render() {
+        const { children } = this.props;
+
+        for(var i in children) {
+            var c = children[i];
+            
+            if(c.props.condition) {
+                return c;
+            }
+        }
+
+        return null;
+    }
+}
+
+export function Option(props) {
+    return props.children;
+}
+
+export function Login(props) {
+    return (
+        <Container className="py-5">
+            <Card className="shadow">
+                <CardBody>
+                    <h1 className="custom-font">Login</h1>
+                    <Hint hint={props.hint}/>
+                    <LoginForm/>
+                    <div className="mt-3">
+                        <a href="/register" className="mr-3">Account anlegen</a>
+                        <a href="/register#account-requirement">Warum ist ein Account nötig?</a>
+                    </div>
+                </CardBody>
+            </Card>
+        </Container>
+    );
+}
+
+class LoginErrorList extends React.Component {
+    render() {
+        const { error, errorMessages } = this.props;
+        if(error) {
+            return (
+                <ul>
+                    { errorMessages.map((message, index) => 
+                        <li key={index}>
+                            <style jsx>{`
+                                li {
+                                    color:red;
+                                }
+                            `}</style>
+                            {message}
+                        </li>
+
+                    ) }
+                </ul>
+            );
+        } else {
+            return null;
+        }
+    }
+}
+
+const mapStateToErrorMessages = (state) => {
+    const { errorMessages, error } = state.userinfo;
+    return { errorMessages, error };
+};
+
+const VisibleLoginErrorList = connect(
+    mapStateToErrorMessages
+)(LoginErrorList);
+
+
+class LoginForm extends React.Component {
+
+    constructor(props) {
+        super(props);
+
+        this.state = {
+            email : '',
+            password : ''
+        };
+    }
+
+    render() {
+        return (
+            <Form>
+                <FormGroup>
+                    <Label for="username">E-Mail-Adresse</Label>
+                    <Input type="email" name="username" value={this.state.email} onChange={ this.handleEmailInput.bind(this) } />
+                </FormGroup>
+                <FormGroup>
+                    <Label for="password">Passwort</Label>
+                    <Input type="password" name="password" value={this.state.password} onChange={ this.handlePasswordInput.bind(this) } />
+                </FormGroup>
+                <Button onClick={login.bind(this, this.state.email, this.state.password)} color="success" size="lg" className="w-100 shadow-sm">Anmelden</Button>
+                <VisibleLoginErrorList/>
+            </Form>
+        );
+    }
+
+    handlePasswordInput(input) {
+        this.setState({ password : input.target.value });
+    }
+
+    handleEmailInput(input) {
+        this.setState({ email : input.target.value });
+    }
+}
+
+function Hint(props) {
+    if(props.hint != null) {
+        return (
+            <h3>{ props.hint }</h3>
+        );
+    } else {
+        return null;
+    }
+}
diff --git a/js/api.js b/js/api.js
index 83f281b..92b9753 100644
--- a/js/api.js
+++ b/js/api.js
@@ -57,6 +57,7 @@ const defaultstate_tournamentinfo = {
     description : '',
     id : -1,
     name : '',
+    ownerUsername : '',
     isPublic : '',
     stages: [],
     teams : []
@@ -272,6 +273,7 @@ const reducer_tournamentinfo = (state = defaultstate_tournamentinfo, action) =>
             description : action.parameters.description,
             id : action.parameters.id,
             name : action.parameters.name,
+            ownerUsername : action.parameters.owner_username,
             isPublic : action.parameters.public,
             stages: action.parameters.stages,
             teams : action.parameters.teams
diff --git a/js/components/ErrorComponents.js b/js/components/ErrorComponents.js
index d33190b..2e84ee9 100644
--- a/js/components/ErrorComponents.js
+++ b/js/components/ErrorComponents.js
@@ -26,7 +26,7 @@ export class ErrorPageComponent extends React.Component {
     }
 }
 
-function ErrorPage(props){
+export function ErrorPage(props){
     return (
         <Container className="mb-5">
             <div className="row mb-5">
diff --git a/pages/create.js b/pages/create.js
index b1606f4..3a25a0b 100644
--- a/pages/create.js
+++ b/pages/create.js
@@ -1,7 +1,8 @@
 import Head from 'next/head';
 import '../static/everypage.css';
-import { Footer, TurniereNavigation } from '../js/CommonComponents';
+import { Footer, TurniereNavigation, UserRestrictor, Option, Login } from '../js/CommonComponents';
 import React from 'react';
+import { connect } from 'react-redux';
 
 import {
     Button,
@@ -22,28 +23,56 @@ import {
 
 import EditableStringList from '../js/EditableStringList';
 
-export default class CreatePage extends React.Component {
+class PrivateCreatePage extends React.Component {
 
     componentDidMount() {
         verifyCredentials();
     }
 
     render() {
+        const { isSignedIn } = this.props;
+
         return (
-            <div className="main generic-fullpage-bg">
-                <Head>
-                    <title>Turnier erstellen: turnie.re</title>
-                </Head>
-                <TurniereNavigation/>
-                <div>
-                    <CreateTournamentCard/>
-                </div>
-                <Footer/>
-            </div>
+            <UserRestrictor>
+                <Option condition={isSignedIn}>
+                    <div className="main generic-fullpage-bg">
+                        <Head>
+                            <title>Turnier erstellen: turnie.re</title>
+                        </Head>
+                        <TurniereNavigation/>
+                        <div>
+                            <CreateTournamentCard/>
+                        </div>
+                        <Footer/>
+                    </div>
+                </Option>
+                <Option condition={true}>
+                    <div className="main generic-fullpage-bg">
+                        <Head>
+                            <title>Anmeldung</title>
+                        </Head>
+                        <TurniereNavigation/>
+                        <div>
+                            <Login hint="Sie müssen angemeldet sein, um diesen Inhalt anzuzeigen!"/>
+                        </div>
+                        <Footer/>
+                    </div>
+                </Option>
+            </UserRestrictor>
         );
     }
-} 
+}
 
+function mapStateToCreatePageProperties(state) {
+    const { isSignedIn } = state.userinfo;
+    return { isSignedIn };
+}
+
+const CreatePage = connect(
+    mapStateToCreatePageProperties
+)(PrivateCreatePage);
+
+export default CreatePage;
 
 function CreateTournamentCard() {
     return (
diff --git a/pages/login.js b/pages/login.js
index 1a58e49..aa43fa5 100644
--- a/pages/login.js
+++ b/pages/login.js
@@ -1,10 +1,7 @@
 import Head from 'next/head';
 import '../static/everypage.css';
-import {Footer, TurniereNavigation} from '../js/CommonComponents';
+import { Footer, TurniereNavigation, Login } from '../js/CommonComponents';
 import React from 'react';
-import { Button, Card, CardBody, Container, Form, FormGroup, Input, Label } from 'reactstrap';
-import { login } from '../js/api';
-import { connect } from 'react-redux';
 
 import {
     verifyCredentials
@@ -31,92 +28,3 @@ export default class LoginPage extends React.Component {
         );
     }
 }
-
-function Login() {
-    return (
-        <Container className="py-5">
-            <Card className="shadow">
-                <CardBody>
-                    <h1 className="custom-font">Login</h1>
-                    <LoginForm/>
-                    <div className="mt-3">
-                        <a href="/register" className="mr-3">Account anlegen</a>
-                        <a href="/register#account-requirement">Warum ist ein Account nötig?</a>
-                    </div>
-                </CardBody>
-            </Card>
-        </Container>
-    );
-}
-
-class LoginErrorList extends React.Component {
-    render() {
-        const { error, errorMessages } = this.props;
-        if(error) {
-            return (
-                <ul>
-                    { errorMessages.map((message, index) => 
-                        <li key={index}>
-                            <style jsx>{`
-                                li {
-                                    color:red;
-                                }
-                            `}</style>
-                            {message}
-                        </li>
-
-                    ) }
-                </ul>
-            );
-        } else {
-            return null;
-        }
-    }
-}
-
-const mapStateToErrorMessages = (state) => {
-    const { errorMessages, error } = state.userinfo;
-    return { errorMessages, error };
-};
-
-const VisibleLoginErrorList = connect(
-    mapStateToErrorMessages
-)(LoginErrorList);
-
-
-class LoginForm extends React.Component {
-
-    constructor(props) {
-        super(props);
-
-        this.state = {
-            email : '',
-            password : ''
-        };
-    }
-
-    render() {
-        return (
-            <Form>
-                <FormGroup>
-                    <Label for="username">E-Mail-Adresse</Label>
-                    <Input type="email" name="username" value={this.state.email} onChange={ this.handleEmailInput.bind(this) } />
-                </FormGroup>
-                <FormGroup>
-                    <Label for="password">Passwort</Label>
-                    <Input type="password" name="password" value={this.state.password} onChange={ this.handlePasswordInput.bind(this) } />
-                </FormGroup>
-                <Button onClick={login.bind(this, this.state.email, this.state.password)} color="success" size="lg" className="w-100 shadow-sm">Anmelden</Button>
-                <VisibleLoginErrorList/>
-            </Form>
-        );
-    }
-
-    handlePasswordInput(input) {
-        this.setState({ password : input.target.value });
-    }
-
-    handleEmailInput(input) {
-        this.setState({ email : input.target.value });
-    }
-}
\ No newline at end of file
diff --git a/pages/tournament-edit.js b/pages/tournament-edit.js
index 0c89d91..1d147c1 100644
--- a/pages/tournament-edit.js
+++ b/pages/tournament-edit.js
@@ -5,7 +5,7 @@ import { connect } from 'react-redux';
 import { notify } from 'react-notify-toast';
 
 import { requestTournament } from '../js/api';
-import { BigImage, Footer, TurniereNavigation } from '../js/CommonComponents.js';
+import { BigImage, Footer, TurniereNavigation, Login, UserRestrictor, Option } from '../js/CommonComponents.js';
 import { ErrorPageComponent } from '../js/components/ErrorComponents.js';
 
 import {
@@ -34,7 +34,7 @@ class EditTournamentPage extends React.Component {
         super(props);
 
         this.state = {
-            validCode: true
+            validCode: false
         };
     }
 
@@ -42,7 +42,10 @@ class EditTournamentPage extends React.Component {
         verifyCredentials();
         requestTournament(this.props.query.code, () => {
             this.setState({ validCode: true });
-            this._edittournamentcontent.notifyOfContentUpdate();
+
+            if(this._edittournamentcontent != null) {
+                this._edittournamentcontent.notifyOfContentUpdate();
+            }
         }, () => {
             this.setState({ validCode: false });
         });
@@ -50,33 +53,50 @@ class EditTournamentPage extends React.Component {
 
     render() {
         const { validCode } = this.state;
-        const { name } = this.props;
+        const { tournamentname, ownerUsername, isSignedIn, username } = this.props;
 
-        if(validCode) {
-            return (
-                <div className='pb-5'>
-                    <Head>
-                        <title>Turnie.re - Turnier bearbeiten</title>
-                    </Head>
-                    <TurniereNavigation/>
-                    <BigImage text={ name }/>
+        return (
+            <UserRestrictor>
+                <Option condition={ validCode && isSignedIn && ownerUsername === username }>
+                    <div className='pb-5'>
+                        <Head>
+                            <title>Turnie.re - Turnier bearbeiten</title>
+                        </Head>
+                        <TurniereNavigation/>
 
-                    <EditTournamentContent ref={(edittournamentcontent) => { this._edittournamentcontent = edittournamentcontent; }}/>
-                    
-                    <Footer/>
-                </div>
-            );
-        } else {
-            return (
-                <ErrorPageComponent statusCode={ 404 }/>
-            );
-        }
+                        <BigImage text={ tournamentname }/>
+                        <EditTournamentContent ref={(edittournamentcontent) => { this._edittournamentcontent = edittournamentcontent; }}/>
+                        <Footer/>
+                    </div>
+                </Option>
+                <Option condition={ validCode && isSignedIn }>
+                    <ErrorPageComponent statusCode={ 403 }/>
+                </Option>
+                <Option condition={ !isSignedIn }>
+                    <div className="main generic-fullpage-bg">
+                        <Head>
+                            <title>Turnie.re - Turnier bearbeiten</title>
+                        </Head>
+                        <TurniereNavigation/>
+
+                        <div>
+                            <Login hint="Sie müssen angemeldet sein, um ein Turnier zu bearbeiten."/>
+                        </div>
+                        <Footer/>
+                    </div>                      
+                </Option>
+                <Option condition={true}>
+                    <ErrorPageComponent statusCode={ 404 }/>
+                </Option>
+            </UserRestrictor>
+        );
     }
 }
 
 function mapStateToTournamentInfo(state) {
-    const { name } = state.tournamentinfo;
-    return { name };
+    const { tournamentname, ownerUsername } = state.tournamentinfo;
+    const { isSignedIn, username } = state.userinfo;
+    return { tournamentname, ownerUsername, isSignedIn, username };
 }
 
 export default connect(
diff --git a/pages/tournament.js b/pages/tournament.js
index 40753f5..779a0ba 100644
--- a/pages/tournament.js
+++ b/pages/tournament.js
@@ -18,10 +18,12 @@ import {
     Row,
     Table
 } from 'reactstrap';
+import { ErrorPageComponent } from '../js/components/ErrorComponents.js';
 import 'bootstrap/dist/css/bootstrap.min.css';
 import {BigImage, Footer, TurniereNavigation} from '../js/CommonComponents.js';
 import '../static/everypage.css';
 import '../static/css/tournament.css';
+import { connect } from 'react-redux';
 
 import {
     getRequest,
@@ -38,7 +40,7 @@ class TournamentPage extends React.Component {
         return (
             <div className='pb-5'>
                 <Container>
-                    <a href={'/t/' + id + '/edit'} className='btn btn-outline-secondary'>Turnier bearbeiten</a>
+                    <EditButton id={id} ownerName={ownerUsername}/>
                     <p>{description}</p>
                     <ListGroup>
                         <ListGroupItem>
@@ -57,6 +59,27 @@ class TournamentPage extends React.Component {
     }
 }
 
+function PrivateEditButton(props) {
+    const { id, ownerName, isSignedIn, username } = props;
+
+    if(isSignedIn && ownerName === username) {
+        return (
+            <a href={'/t/' + id + '/edit'} className='btn btn-outline-secondary'>Turnier bearbeiten</a>
+        );
+    } else {
+        return null;
+    }
+}
+
+function mapStateToEditButtonProperties(state) {
+    const { isSignedIn, username } = state.userinfo;
+    return { isSignedIn, username };
+}
+
+const EditButton = connect(
+    mapStateToEditButtonProperties
+)(PrivateEditButton);
+
 function getLevelName(levelNumber) {
     const names = ['Finale', 'Halbfinale', 'Viertelfinale', 'Achtelfinale'];
     if(levelNumber < names.length){
@@ -66,16 +89,6 @@ function getLevelName(levelNumber) {
     }
 }
 
-function TournamentContainer(props) {
-    const { tournament } = props.data;
-
-    if (tournament === null) {
-        return <Container>null</Container>;
-    } else {
-        return <TournamentPage tournament={tournament}/>;
-    }
-}
-
 function Stage(props) {
     return (<div>
         <Container className='py-5'>
@@ -371,25 +384,34 @@ class Main extends React.Component {
 
         getRequest(getState(), '/tournaments/' + code)
             .then(response => {
-                this.setState({tournament: convertTournament(response.data)});
+                this.setState({ status : response.status, tournament : convertTournament(response.data)});
             })
-            .catch(() => { /* TODO: Show some kind of error or smth */ });
+            .catch((err) => {
+                this.setState({ status : err.response.status });
+            });
     }
 
 
     render() {
         const tournamentName = this.state.tournament === null ? 'Turnier' : this.state.tournament.name;
-        return (
-            <div>
-                <Head>
-                    <title>{tournamentName}: turnie.re</title>
-                </Head>
-                <TurniereNavigation/>
-                <BigImage text={tournamentName}/>
-                <TournamentContainer data={this.state}/>
-                <Footer/>
-            </div>
-        );
+
+        const { status, tournament } = this.state;
+
+        if (status == 200) {
+            return (
+                <div>
+                    <Head>
+                        <title>{tournamentName}: turnie.re</title>
+                    </Head>
+                    <TurniereNavigation/>
+                    <BigImage text={tournamentName}/>
+                    <TournamentPage tournament={tournament}/>
+                    <Footer/>
+                </div>
+            );
+        } else {
+            return <ErrorPageComponent code={status}/>;
+        }
     }
 }