Compile the project with Java 7. Many hosters don't have Java 8 yet.

.gitignore

@@ -1,8 +1,42 @@
-target/
-pom.xml.tag
-pom.xml.releaseBackup
-pom.xml.versionsBackup
-pom.xml.next
-release.properties
-dependency-reduced-pom.xml
-buildNumber.properties
+# Eclipse stuff
+/.classpath
+/.project
+/.settings
+
+# netbeans
+/nbproject
+nb-configuration.xml
+
+# maven
+/target
+
+# vim
+.*.sw[a-p]
+
+# virtual machine crash logs, see http://www.java.com/en/download/help/error_hotspot.xml
+hs_err_pid*
+
+# various other potential build files
+/build
+/bin
+/dist
+/manifest.mf
+*.log
+
+# Mac filesystem dust
+.DS_Store
+
+# intellij
+*.iml
+*.ipr
+*.iws
+.idea/
+
+# Gradle
+.gradle
+
+# Ignore Gradle GUI config
+gradle-app.setting
+
+# Avoid ignoring Gradle wrapper jar file (.jar files are usually ignored)
+!gradle-wrapper.jar

README.md

@@ -1,2 +1,13 @@
 # FastLogin
-Checks if a minecraft player has a valid paid account. If so, they can skip offline authentification.
+
+Checks if a minecraft player has a valid premium (paid account). If so, they can skip offline authentification.
+
+Requirements:
+* [ProtocolLib](http://www.spigotmc.org/resources/protocollib.1997/)
+* Bukkit 1.8.8
+* Java 8 or above
+* An auth plugin. Supported Plugins:
+    * [AuthMe](http://dev.bukkit.org/bukkit-plugins/authme-reloaded/)
+    * [xAuth](http://dev.bukkit.org/bukkit-plugins/xauth/)
+    * [CrazyLogin](http://dev.bukkit.org/bukkit-plugins/crazylogin/)
+    * [LoginSecurity](http://dev.bukkit.org/bukkit-plugins/loginsecurity/)

pom.xml

@@ -0,0 +1,173 @@
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+
+    <groupId>com.github.games647</groupId>
+    <!--This have to be in lowercase because it's used by plugin.yml-->
+    <artifactId>fastlogin</artifactId>
+    <packaging>jar</packaging>
+
+    <name>FastLogin</name>
+    <version>0.2.2</version>
+    <inceptionYear>2015</inceptionYear>
+    <url>https://github.com/games647/FastLogin</url>
+    <description>
+        Automatically logins premium (paid accounts) player on a offline mode server
+    </description>
+
+    <properties>
+        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+        <!--Possibility to deploy directly to the plugins folder-->
+        <outputDir>${basedir}/target</outputDir>
+    </properties>
+
+    <issueManagement>
+        <system>GitHub</system>
+        <url>https://github.com/games647/FastLogin/issues</url>
+    </issueManagement>
+
+    <scm>
+        <url>https://github.com/games647/FastLogin</url>
+        <connection>scm:git:git://github.com/games647/FastLogin.git</connection>
+        <developerConnection>scm:git:ssh://git@github.com:games647/FastLogin.git</developerConnection>
+    </scm>
+
+    <build>
+        <defaultGoal>install</defaultGoal>
+        <!--Just use the project name to replace an old version of the plugin if the user does only copy-paste-->
+        <finalName>${project.name}</finalName>
+
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <version>3.2</version>
+                <configuration>
+                    <source>1.7</source>
+                    <target>1.7</target>
+                    <showWarnings>true</showWarnings>
+                    <showDeprecation>true</showDeprecation>
+                    <!--false means actual true http://jira.codehaus.org/browse/MCOMPILER-209-->
+                    <useIncrementalCompilation>false</useIncrementalCompilation>
+                </configuration>
+            </plugin>
+
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-jar-plugin</artifactId>
+                <version>2.6</version>
+                <configuration>
+                    <outputDirectory>${outputDir}</outputDirectory>
+                </configuration>
+            </plugin>
+        </plugins>
+
+        <resources>
+            <resource>
+                <directory>src/main/resources</directory>
+                <!--Replace variables-->
+                <filtering>true</filtering>
+            </resource>
+
+            <!--Add the license to jar in order to see it in the final jar-->
+            <resource>
+                <directory>${basedir}</directory>
+                <includes>
+                    <include>LICENSE</include>
+                </includes>
+            </resource>
+        </resources>
+    </build>
+
+    <repositories>
+        <!--Bukkit-Server-API -->
+        <repository>
+            <id>spigot-repo</id>
+            <url>https://hub.spigotmc.org/nexus/content/repositories/snapshots/</url>
+        </repository>
+
+        <!--ProtocolLib-->
+        <repository>
+            <id>dmulloy2-repo</id>
+            <url>http://repo.dmulloy2.net/content/groups/public/</url>
+        </repository>
+
+        <!--Authme Reloaded-->
+        <repository>
+            <id>xephi-repo</id>
+            <url>http://ci.xephi.fr/plugin/repository/everything/</url>
+        </repository>
+
+        <!--xAuth-->
+        <repository>
+            <id>luricos.de-repo</id>
+            <url>http://repo.luricos.de/bukkit-plugins/</url>
+        </repository>
+    </repositories>
+
+    <dependencies>
+        <!--Server API-->
+        <dependency>
+            <groupId>org.spigotmc</groupId>
+            <artifactId>spigot-api</artifactId>
+            <version>1.8.8-R0.1-SNAPSHOT</version>
+            <scope>provided</scope>
+        </dependency>
+
+        <!--Library for listening and sending Minecraft packets-->
+        <dependency>
+            <groupId>com.comphenix.protocol</groupId>
+            <artifactId>ProtocolLib</artifactId>
+            <version>3.6.5-SNAPSHOT</version>
+            <optional>true</optional>
+        </dependency>
+
+        <!--Login Plugins-->
+        <dependency>
+            <groupId>fr.xephi</groupId>
+            <artifactId>authme</artifactId>
+            <version>5.0-SNAPSHOT</version>
+        </dependency>
+
+        <dependency>
+            <groupId>de.luricos.bukkit</groupId>
+            <artifactId>xAuth</artifactId>
+            <version>2.6</version>
+            <!--These artifacts produce conflicts on downloading-->
+            <exclusions>
+                <exclusion>
+                    <groupId>net.gravitydevelopment.updater</groupId>
+                    <artifactId>updater</artifactId>
+                </exclusion>
+                <exclusion>
+                    <groupId>net.ess3</groupId>
+                    <artifactId>EssentialsGroupManager</artifactId>
+                </exclusion>
+            </exclusions>
+        </dependency>
+
+        <dependency>
+            <groupId>de.st_ddt.crazy</groupId>
+            <artifactId>CrazyCore</artifactId>
+            <version>10.7.7</version>
+            <scope>system</scope>
+            <systemPath>${project.basedir}/lib/CrazyCore v10.7.7.jar</systemPath>
+        </dependency>
+
+        <dependency>
+            <groupId>de.st_ddt.crazy</groupId>
+            <artifactId>CrazyLogin</artifactId>
+            <version>7.23</version>
+            <scope>system</scope>
+            <systemPath>${project.basedir}/lib/CrazyLogin v7.23.2.jar</systemPath>
+        </dependency>
+
+        <dependency>
+            <groupId>me.lenis0012.ls</groupId>
+            <artifactId>LoginSecurity</artifactId>
+            <version>2.0.10</version>
+            <scope>system</scope>
+            <systemPath>${project.basedir}/lib/LoginSecurity v2.0.10.jar</systemPath>
+        </dependency>
+    </dependencies>
+</project>

src/main/java/com/github/games647/fastlogin/Encryption.java

@@ -0,0 +1,125 @@
+package com.github.games647.fastlogin;
+
+import com.google.common.base.Charsets;
+
+import java.security.GeneralSecurityException;
+import java.security.InvalidKeyException;
+import java.security.Key;
+import java.security.KeyFactory;
+import java.security.KeyPair;
+import java.security.KeyPairGenerator;
+import java.security.MessageDigest;
+import java.security.NoSuchAlgorithmException;
+import java.security.PrivateKey;
+import java.security.PublicKey;
+import java.security.spec.InvalidKeySpecException;
+import java.security.spec.X509EncodedKeySpec;
+
+import javax.crypto.BadPaddingException;
+import javax.crypto.Cipher;
+import javax.crypto.IllegalBlockSizeException;
+import javax.crypto.NoSuchPaddingException;
+import javax.crypto.SecretKey;
+import javax.crypto.spec.IvParameterSpec;
+import javax.crypto.spec.SecretKeySpec;
+
+/**
+ * Source: https://github.com/bergerkiller/CraftSource/blob/master/net.minecraft.server/MinecraftEncryption.java
+ *
+ * Remapped by: https://github.com/Techcable/MinecraftMappings/tree/master/1.8
+ */
+public class Encryption {
+
+    public static KeyPair generateKeyPair() {
+        try {
+            KeyPairGenerator keypairgenerator = KeyPairGenerator.getInstance("RSA");
+
+            keypairgenerator.initialize(1024);
+            return keypairgenerator.generateKeyPair();
+        } catch (NoSuchAlgorithmException nosuchalgorithmexception) {
+            //Should be existing in every vm
+            return null;
+        }
+    }
+
+    public static byte[] getServerIdHash(String serverId, PublicKey publickey, SecretKey secretkey) {
+        return digestOperation("SHA-1"
+                , new byte[][]{serverId.getBytes(Charsets.ISO_8859_1), secretkey.getEncoded(), publickey.getEncoded()});
+    }
+
+    private static byte[] digestOperation(String algo, byte[]... content) {
+        try {
+            MessageDigest messagedigest = MessageDigest.getInstance(algo);
+            for (byte[] data : content) {
+                messagedigest.update(data);
+            }
+
+            return messagedigest.digest();
+        } catch (NoSuchAlgorithmException nosuchalgorithmexception) {
+            nosuchalgorithmexception.printStackTrace();
+            return null;
+        }
+    }
+
+    public static PublicKey decodePublicKey(byte[] encodedKey) {
+        try {
+            X509EncodedKeySpec x509encodedkeyspec = new X509EncodedKeySpec(encodedKey);
+            KeyFactory keyfactory = KeyFactory.getInstance("RSA");
+
+            return keyfactory.generatePublic(x509encodedkeyspec);
+        } catch (NoSuchAlgorithmException | InvalidKeySpecException nosuchalgorithmexception) {
+            ;
+        }
+
+        System.err.println("Public key reconstitute failed!");
+        return null;
+    }
+
+    public static SecretKey decryptSharedKey(PrivateKey privatekey, byte[] encryptedSharedKey) {
+        return new SecretKeySpec(decryptData(privatekey, encryptedSharedKey), "AES");
+    }
+
+    public static byte[] decryptData(Key key, byte[] abyte) {
+        return cipherOperation(Cipher.DECRYPT_MODE, key, abyte);
+    }
+
+    private static byte[] cipherOperation(int operationMode, Key key, byte[] data) {
+        try {
+            return createCipherInstance(operationMode, key.getAlgorithm(), key).doFinal(data);
+        } catch (IllegalBlockSizeException | BadPaddingException illegalblocksizeexception) {
+            illegalblocksizeexception.printStackTrace();
+        }
+
+        System.err.println("Cipher data failed!");
+        return null;
+    }
+
+    private static Cipher createCipherInstance(int operationMode, String cipherName, Key key) {
+        try {
+            Cipher cipher = Cipher.getInstance(cipherName);
+
+            cipher.init(operationMode, key);
+            return cipher;
+        } catch (InvalidKeyException | NoSuchAlgorithmException | NoSuchPaddingException invalidkeyexception) {
+            invalidkeyexception.printStackTrace();
+        }
+
+        System.err.println("Cipher creation failed!");
+        return null;
+    }
+
+    public static Cipher createBufferedBlockCipher(int operationMode, Key key) {
+        try {
+            Cipher cipher = Cipher.getInstance("AES/CFB8/NoPadding");
+
+            cipher.init(operationMode, key, new IvParameterSpec(key.getEncoded()));
+            return cipher;
+        } catch (GeneralSecurityException generalsecurityexception) {
+            throw new RuntimeException(generalsecurityexception);
+        }
+    }
+
+    private Encryption() {
+        //utility
+    }
+}

src/main/java/com/github/games647/fastlogin/FastLogin.java

@@ -0,0 +1,164 @@
+package com.github.games647.fastlogin;
+
+import com.github.games647.fastlogin.listener.PlayerListener;
+import com.comphenix.protocol.ProtocolLibrary;
+import com.comphenix.protocol.ProtocolManager;
+import com.comphenix.protocol.utility.SafeCacheBuilder;
+import com.github.games647.fastlogin.hooks.AuthPlugin;
+import com.github.games647.fastlogin.listener.EncryptionPacketListener;
+import com.github.games647.fastlogin.listener.StartPacketListener;
+import com.google.common.cache.CacheLoader;
+import com.google.common.collect.Sets;
+import com.google.common.reflect.ClassPath;
+
+import java.io.IOException;
+import java.net.HttpURLConnection;
+import java.net.URL;
+import java.security.KeyPair;
+import java.util.Set;
+import java.util.concurrent.ConcurrentMap;
+import java.util.concurrent.TimeUnit;
+import java.util.logging.Level;
+
+import org.bukkit.plugin.java.JavaPlugin;
+
+public class FastLogin extends JavaPlugin {
+
+    private static final int TIMEOUT = 15000;
+    private static final String USER_AGENT = "Premium-Checker";
+
+    //provide a immutable key pair to be thread safe
+    private final KeyPair keyPair = Encryption.generateKeyPair();
+
+    //we need a thread-safe set because we access it async in the packet listener
+    private final Set<String> enabledPremium = Sets.newConcurrentHashSet();
+
+    //this map is thread-safe for async access (Packet Listener)
+    //SafeCacheBuilder is used in order to be version independent
+    private final ConcurrentMap<String, PlayerSession> session = SafeCacheBuilder.<String, PlayerSession>newBuilder()
+            //mapped by ip:port
+            .expireAfterWrite(2, TimeUnit.MINUTES)
+            //2 minutes should be enough as a timeout for bad internet connection (Server, Client and Mojang)
+            .build(new CacheLoader<String, PlayerSession>() {
+
+                @Override
+                public PlayerSession load(String key) throws Exception {
+                    //A key should be inserted manually on start packet
+                    throw new UnsupportedOperationException("Not supported");
+                }
+            });
+
+    @Override
+    public void onLoad() {
+        //online mode is only changeable after a restart so check it here
+        if (getServer().getOnlineMode()) {
+            getLogger().severe("Server have to be in offline mode");
+
+            setEnabled(false);
+        }
+    }
+
+    @Override
+    public void onEnable() {
+        if (!isEnabled() || !registerHooks()) {
+            return;
+        }
+
+        //register packet listeners on success
+        ProtocolManager protocolManager = ProtocolLibrary.getProtocolManager();
+        protocolManager.addPacketListener(new EncryptionPacketListener(this, protocolManager));
+        protocolManager.addPacketListener(new StartPacketListener(this, protocolManager));
+
+        //register commands
+        getCommand("premium").setExecutor(new PremiumCommand(this));
+    }
+
+    @Override
+    public void onDisable() {
+        //clean up
+        session.clear();
+        enabledPremium.clear();
+    }
+
+    /**
+     * Gets a thread-safe map about players which are connecting to the server are being checked to be premium (paid
+     * account)
+     *
+     * @return a thread-safe session map
+     */
+    public ConcurrentMap<String, PlayerSession> getSessions() {
+        return session;
+    }
+
+    /**
+     * Gets the server KeyPair
+     *
+     * @return the server KeyPair
+     */
+    public KeyPair getKeyPair() {
+        return keyPair;
+    }
+
+    /**
+     * Gets a set of user who activated premium logins
+     *
+     * @return user who activated premium logins
+     */
+    public Set<String> getEnabledPremium() {
+        return enabledPremium;
+    }
+
+    /**
+     * Prepares a Mojang API connection. The connection is not started in this method
+     *
+     * @param url the url connecting to
+     * @return the prepared connection
+     *
+     * @throws IOException on invalid url format or on {@link java.net.URL#openConnection() }
+     */
+    public HttpURLConnection getConnection(String url) throws IOException {
+        HttpURLConnection connection = (HttpURLConnection) new URL(url).openConnection();
+        connection.setConnectTimeout(TIMEOUT);
+        connection.setReadTimeout(TIMEOUT);
+        //the new Mojang API just uses json as response
+        connection.setRequestProperty("Content-Type", "application/json");
+        connection.setRequestProperty("User-Agent", USER_AGENT);
+
+        return connection;
+    }
+
+    private boolean registerHooks() {
+        AuthPlugin authPluginHook = null;
+        try {
+            String hooksPackage = this.getClass().getPackage().getName() + ".hooks";
+            //Look through all classes in the hooks package and look for supporting plugins on the server
+            for (ClassPath.ClassInfo clazzInfo : ClassPath.from(getClassLoader()).getTopLevelClasses(hooksPackage)) {
+                //remove the hook suffix
+                String pluginName = clazzInfo.getSimpleName().replace("Hook", "");
+                Class<?> clazz = clazzInfo.load();
+                //uses only member classes which uses AuthPlugin interface (skip interfaces)
+                if (AuthPlugin.class.isAssignableFrom(clazz)
+                        && getServer().getPluginManager().isPluginEnabled(pluginName)) {
+                    authPluginHook = (AuthPlugin) clazz.newInstance();
+                    getLogger().log(Level.INFO, "Hooking into auth plugin: {0}", pluginName);
+                    break;
+                }
+            }
+        } catch (InstantiationException | IllegalAccessException | IOException ex) {
+            getLogger().log(Level.SEVERE, "Couldn't load the integration class", ex);
+        }
+
+        if (authPluginHook == null) {
+            //run this check for exceptions and not found plugins
+            getLogger().warning("No support offline Auth plugin found. ");
+            getLogger().warning("Disabling this plugin...");
+
+            setEnabled(false);
+            return false;
+        }
+
+        //We found a supporting plugin - we can now register a forwarding listener
+        getServer().getPluginManager().registerEvents(new PlayerListener(this, authPluginHook), this);
+        return true;
+    }
+}

src/main/java/com/github/games647/fastlogin/PlayerSession.java

@@ -0,0 +1,56 @@
+package com.github.games647.fastlogin;
+
+/**
+ * Represents a client connecting to the server.
+ *
+ * This session is invalid if the player disconnects or the login was successful
+ */
+public class PlayerSession {
+
+    private final byte[] verifyToken;
+    private final String username;
+    private boolean verified;
+
+    public PlayerSession(byte[] verifyToken, String username) {
+        this.username = username;
+        this.verifyToken = verifyToken;
+    }
+
+    /**
+     * Gets the verify token the server sent to the client.
+     *
+     * @return the verify token from the server
+     */
+    public byte[] getVerifyToken() {
+        return verifyToken;
+    }
+
+    /**
+     * Gets the username the player sent to the server
+     *
+     * @return the client sent username
+     */
+    public String getUsername() {
+        return username;
+    }
+
+    /**
+     * Sets whether the player has a premium (paid account) account
+     * and valid session
+     *
+     * @param verified whether the player has valid session
+     */
+    public synchronized void setVerified(boolean verified) {
+        this.verified = verified;
+    }
+
+    /**
+     * Get whether the player has a premium (paid account) account
+     * and valid session
+     *
+     * @return whether the player has a valid session
+     */
+    public synchronized boolean isVerified() {
+        return verified;
+    }
+}

src/main/java/com/github/games647/fastlogin/PremiumCommand.java

@@ -0,0 +1,45 @@
+package com.github.games647.fastlogin;
+
+import org.bukkit.ChatColor;
+import org.bukkit.command.Command;
+import org.bukkit.command.CommandExecutor;
+import org.bukkit.command.CommandSender;
+import org.bukkit.entity.Player;
+
+public class PremiumCommand implements CommandExecutor {
+
+    private final FastLogin plugin;
+
+    public PremiumCommand(FastLogin plugin) {
+        this.plugin = plugin;
+    }
+
+    @Override
+    public boolean onCommand(CommandSender sender, Command command, String label, String[] args) {
+        if (args.length == 0) {
+            if (!(sender instanceof Player)) {
+                //console or command block
+                sender.sendMessage(ChatColor.DARK_RED + "Only players can add themselves as premium");
+                return true;
+            }
+
+            String playerName = sender.getName();
+            plugin.getEnabledPremium().add(playerName);
+            sender.sendMessage(ChatColor.DARK_GREEN + "Added to the list of premium players");
+            return true;
+        }
+
+        if (sender.hasPermission(plugin.getName() + ".command." + command.getName() + ".others")) {
+            String playerName = args[0];
+            //todo check if valid username
+            plugin.getEnabledPremium().add(playerName);
+            sender.sendMessage(ChatColor.DARK_GREEN + "Added "
+                    + ChatColor.DARK_BLUE + ChatColor.BOLD + playerName
+                    + ChatColor.RESET + ChatColor.DARK_GREEN + " to the list of premium players");
+        } else {
+            sender.sendMessage(ChatColor.DARK_RED + "Not enough permissions");
+        }
+
+        return true;
+    }
+}

src/main/java/com/github/games647/fastlogin/hooks/AuthMeHook.java

@@ -0,0 +1,25 @@
+package com.github.games647.fastlogin.hooks;
+
+import fr.xephi.authme.api.NewAPI;
+import fr.xephi.authme.cache.limbo.LimboCache;
+
+import org.bukkit.entity.Player;
+
+/**
+ * Github: https://github.com/Xephi/AuthMeReloaded/
+ * Project page: http://dev.bukkit.org/bukkit-plugins/authme-reloaded/
+ */
+public class AuthMeHook implements AuthPlugin {
+
+    @Override
+    public void forceLogin(Player player) {
+        //here is the gamemode, inventory ... saved
+        if (!LimboCache.getInstance().hasLimboPlayer(player.getName().toLowerCase())) {
+            //add cache entry - otherwise logging in wouldn't work
+            LimboCache.getInstance().addLimboPlayer(player);
+        }
+
+        //skips registration and login
+        NewAPI.getInstance().forceLogin(player);
+    }
+}

src/main/java/com/github/games647/fastlogin/hooks/AuthPlugin.java

@@ -0,0 +1,16 @@
+package com.github.games647.fastlogin.hooks;
+
+import org.bukkit.entity.Player;
+
+/**
+ * Represents a supporting authentication plugin
+ */
+public interface AuthPlugin {
+
+    /**
+     * Login the premium (paid account) player
+     *
+     * @param player the player that needs to be logged in
+     */
+    void forceLogin(Player player);
+}

src/main/java/com/github/games647/fastlogin/hooks/CrazyLoginHook.java

@@ -0,0 +1,31 @@
+package com.github.games647.fastlogin.hooks;
+
+import de.st_ddt.crazylogin.CrazyLogin;
+import de.st_ddt.crazylogin.data.LoginPlayerData;
+import de.st_ddt.crazylogin.databases.CrazyLoginDataDatabase;
+
+import org.bukkit.entity.Player;
+
+/**
+ * Github: https://github.com/ST-DDT/CrazyLogin
+ * Project page: http://dev.bukkit.org/server-mods/crazylogin/
+ */
+public class CrazyLoginHook implements AuthPlugin {
+
+    @Override
+    public void forceLogin(Player player) {
+        CrazyLogin crazyLoginPlugin = CrazyLogin.getPlugin();
+        CrazyLoginDataDatabase crazyDatabase = crazyLoginPlugin.getCrazyDatabase();
+
+        LoginPlayerData playerData = crazyLoginPlugin.getPlayerData(player.getName());
+        if (playerData == null) {
+            //create a fake account - this will be saved to the database with the password=FAILEDLOADING
+            //user cannot login with that password unless the admin uses plain text
+            playerData = new LoginPlayerData(player);
+            crazyDatabase.save(playerData);
+        } else {
+            //mark the account as logged in
+            playerData.setLoggedIn(true);
+        }
+    }
+}

src/main/java/com/github/games647/fastlogin/hooks/LoginSecurityHook.java

@@ -0,0 +1,30 @@
+package com.github.games647.fastlogin.hooks;
+
+import com.lenis0012.bukkit.ls.LoginSecurity;
+
+import org.bukkit.entity.Player;
+
+/**
+ * Github: http://dev.bukkit.org/bukkit-plugins/loginsecurity/
+ * Project page: https://github.com/lenis0012/LoginSecurity-2
+ *
+ * on join:
+ * https://github.com/lenis0012/LoginSecurity-2/blob/master/src/main/java/com/lenis0012/bukkit/ls/LoginSecurity.java#L282
+ */
+public class LoginSecurityHook implements AuthPlugin {
+
+    @Override
+    public void forceLogin(Player player) {
+        //Login command of this plugin: (How the plugin logs the player in)
+        //https://github.com/lenis0012/LoginSecurity-2/blob/master/src/main/java/com/lenis0012/bukkit/ls/commands/LoginCommand.java#L39
+        LoginSecurity securityPlugin = LoginSecurity.instance;
+        String name = player.getName().toLowerCase();
+
+        //mark the user as logged in
+        securityPlugin.authList.remove(name);
+        //cancel timeout timer
+        securityPlugin.thread.timeout.remove(name);
+        //remove effects
+        securityPlugin.rehabPlayer(player, name);
+    }
+}

src/main/java/com/github/games647/fastlogin/hooks/xAuthHook.java

@@ -0,0 +1,36 @@
+package com.github.games647.fastlogin.hooks;
+
+import de.luricos.bukkit.xAuth.xAuth;
+import de.luricos.bukkit.xAuth.xAuthPlayer;
+import de.luricos.bukkit.xAuth.xAuthPlayer.Status;
+
+import java.sql.Timestamp;
+
+import org.bukkit.entity.Player;
+
+/**
+ * Github: https://github.com/LycanDevelopment/xAuth/
+ * Project page: http://dev.bukkit.org/bukkit-plugins/xauth/
+ */
+public class xAuthHook implements AuthPlugin {
+
+    @Override
+    public void forceLogin(Player player) {
+        xAuth xAuthPlugin = xAuth.getPlugin();
+
+        xAuthPlayer xAuthPlayer = xAuthPlugin.getPlayerManager().getPlayer(player);
+        //we checked that the player is premium (paid account)
+        xAuthPlayer.setPremium(true);
+        //mark the player online
+        xAuthPlugin.getAuthClass(xAuthPlayer).online(xAuthPlayer.getName());
+
+        //update last login time
+        xAuthPlayer.setLoginTime(new Timestamp(System.currentTimeMillis()));
+
+        //mark the player as logged in
+        xAuthPlayer.setStatus(Status.AUTHENTICATED);
+
+        //restore inventory
+        xAuthPlugin.getPlayerManager().unprotect(xAuthPlayer);
+    }
+}

src/main/java/com/github/games647/fastlogin/listener/EncryptionPacketListener.java

@@ -0,0 +1,201 @@
+package com.github.games647.fastlogin.listener;
+
+import com.comphenix.protocol.PacketType;
+import com.comphenix.protocol.ProtocolManager;
+import com.comphenix.protocol.events.PacketAdapter;
+import com.comphenix.protocol.events.PacketContainer;
+import com.comphenix.protocol.events.PacketEvent;
+import com.comphenix.protocol.injector.server.TemporaryPlayerFactory;
+import com.comphenix.protocol.reflect.FuzzyReflection;
+import com.comphenix.protocol.wrappers.WrappedGameProfile;
+import com.github.games647.fastlogin.Encryption;
+import com.github.games647.fastlogin.FastLogin;
+import com.github.games647.fastlogin.PlayerSession;
+
+import java.io.BufferedReader;
+import java.io.InputStreamReader;
+import java.lang.reflect.Field;
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+import java.math.BigInteger;
+import java.net.HttpURLConnection;
+import java.security.PrivateKey;
+import java.util.Arrays;
+import java.util.logging.Level;
+
+import javax.crypto.SecretKey;
+
+import org.bukkit.Bukkit;
+import org.bukkit.entity.Player;
+import org.json.simple.JSONObject;
+import org.json.simple.JSONValue;
+
+/**
+ * Receiving packet information:
+ * http://wiki.vg/Protocol#Encryption_Response
+ *
+ * sharedSecret=encrypted byte array
+ * verify token=encrypted byte array
+ */
+public class EncryptionPacketListener extends PacketAdapter {
+
+    private static final String HAS_JOINED_URL = "https://sessionserver.mojang.com/session/minecraft/hasJoined?";
+
+    private final ProtocolManager protocolManager;
+    //hides the inherit Plugin plugin field, but we need this type
+    private final FastLogin plugin;
+
+    public EncryptionPacketListener(FastLogin plugin, ProtocolManager protocolManger) {
+        //run async in order to not block the server, because we make api calls to Mojang
+        super(params(plugin, PacketType.Login.Client.ENCRYPTION_BEGIN).optionAsync());
+
+        this.plugin = plugin;
+        this.protocolManager = protocolManger;
+    }
+
+    /**
+     * C->S : Handshake State=2
+     * C->S : Login Start
+     * S->C : Encryption Key Request
+     * (Client Auth)
+     * C->S : Encryption Key Response
+     * (Server Auth, Both enable encryption)
+     * S->C : Login Success (*)
+     *
+     * On offline logins is Login Start followed by Login Success
+     *
+     * Minecraft Server implementation
+     * https://github.com/bergerkiller/CraftSource/blob/master/net.minecraft.server/LoginListener.java#L180
+     */
+    @Override
+    public void onPacketReceiving(PacketEvent packetEvent) {
+        PacketContainer packet = packetEvent.getPacket();
+        Player player = packetEvent.getPlayer();
+
+        //the player name is unknown to ProtocolLib - now uses ip:port as key
+        String uniqueSessionKey = player.getAddress().toString();
+        PlayerSession session = plugin.getSessions().get(uniqueSessionKey);
+        if (session == null) {
+            disconnect(packetEvent, "Invalid request", Level.FINE
+                    , "Player {0} tried to send encryption response"
+                            + "on an invalid connection state"
+                    , player.getAddress());
+            return;
+        }
+
+        byte[] sharedSecret = packet.getByteArrays().read(0);
+        byte[] clientVerify = packet.getByteArrays().read(1);
+
+        PrivateKey privateKey = plugin.getKeyPair().getPrivate();
+        byte[] serverVerify = session.getVerifyToken();
+        //https://github.com/bergerkiller/CraftSource/blob/master/net.minecraft.server/LoginListener.java#L182
+        if (!Arrays.equals(serverVerify, Encryption.decryptData(privateKey, clientVerify))) {
+            //check if the verify token are equal to the server sent one
+            disconnect(packetEvent, "Invalid token", Level.FINE
+                    , "Player {0} ({1}) tried to login with an invalid verify token. "
+                            + "Server: {2} Client: {3}"
+                    , session.getUsername(), player.getAddress(), serverVerify, clientVerify);
+            return;
+        }
+
+        SecretKey loginKey = Encryption.decryptSharedKey(privateKey, sharedSecret);
+        try {
+            //get the NMS connection handle of this player
+            Object networkManager = getNetworkManager(player);
+
+            //try to detect the method by parameters
+            Method encryptConnectionMethod = FuzzyReflection.fromObject(networkManager)
+                    .getMethodByParameters("a", SecretKey.class);
+
+            //encrypt/decrypt following packets
+            //the client expects this behaviour
+            encryptConnectionMethod.invoke(networkManager, loginKey);
+        } catch (ReflectiveOperationException ex) {
+            disconnect(packetEvent, "Error occurred", Level.SEVERE, "Couldn't enable encryption", ex);
+            return;
+        }
+
+        //https://github.com/bergerkiller/CraftSource/blob/master/net.minecraft.server/LoginListener.java#L193
+        //generate the server id based on client and server data
+        String serverId = (new BigInteger(Encryption.getServerIdHash("", plugin.getKeyPair().getPublic(), loginKey)))
+                .toString(16);
+
+        String username = session.getUsername();
+        if (hasJoinedServer(username, serverId)) {
+            session.setVerified(true);
+
+            plugin.getLogger().log(Level.FINE, "Player {0} has a verified premium account", username);
+
+            receiveFakeStartPacket(username, player);
+        } else {
+            //user tried to fake a authentification
+            disconnect(packetEvent, "Invalid session", Level.FINE
+                    , "Player {0} ({1}) tried to log in with an invalid session ServerId: {2}"
+                    , session.getUsername(), player.getAddress(), serverId);
+        }
+
+        packetEvent.setCancelled(true);
+    }
+
+    private void disconnect(PacketEvent packetEvent, String kickMessage, Level logLevel, String logMessage
+            , Object... arguments) {
+        plugin.getLogger().log(logLevel, logMessage, arguments);
+        packetEvent.getPlayer().kickPlayer(kickMessage);
+        //cancel the event in order to prevent the server receiving an invalid packet
+        packetEvent.setCancelled(true);
+    }
+
+    private Object getNetworkManager(Player player)
+            throws SecurityException, IllegalAccessException, NoSuchFieldException {
+        Object injector = TemporaryPlayerFactory.getInjectorFromPlayer(player);
+        Field injectorField = injector.getClass().getDeclaredField("injector");
+        injectorField.setAccessible(true);
+
+        Object rawInjector = injectorField.get(injector);
+
+        injectorField = rawInjector.getClass().getDeclaredField("networkManager");
+        injectorField.setAccessible(true);
+        return injectorField.get(rawInjector);
+    }
+
+    private boolean hasJoinedServer(String username, String serverId) {
+        try {
+            String url = HAS_JOINED_URL + "username=" + username + "&serverId=" + serverId;
+
+            HttpURLConnection conn = plugin.getConnection(url);
+
+            BufferedReader reader = new BufferedReader(new InputStreamReader(conn.getInputStream()));
+            String line = reader.readLine();
+            if (!line.equals("null")) {
+                //validate parsing
+                JSONObject object = (JSONObject) JSONValue.parseWithException(line);
+                String uuid = (String) object.get("id");
+                String name = (String) object.get("name");
+
+                return true;
+            }
+        } catch (Exception ex) {
+            //catch not only ioexceptions also parse and NPE on unexpected json format
+            plugin.getLogger().log(Level.WARNING, "Failed to verify if session is valid", ex);
+        }
+        //this connection doesn't need to be closed. So can make use of keep alive in java
+
+        return false;
+    }
+
+    private void receiveFakeStartPacket(String username, Player from) {
+        //fake a new login packet
+        //see StartPacketListener for packet information
+        PacketContainer startPacket = protocolManager.createPacket(PacketType.Login.Client.START, true);
+
+        WrappedGameProfile fakeProfile = WrappedGameProfile.fromOfflinePlayer(Bukkit.getOfflinePlayer(username));
+        startPacket.getGameProfiles().write(0, fakeProfile);
+        try {
+            protocolManager.recieveClientPacket(from, startPacket, false);
+        } catch (InvocationTargetException | IllegalAccessException ex) {
+            plugin.getLogger().log(Level.WARNING, "Failed to fake a new start packet", ex);
+            //cancel the event in order to prevent the server receiving an invalid packet
+            from.kickPlayer("Error occurred");
+        }
+    }
+}

src/main/java/com/github/games647/fastlogin/listener/PlayerListener.java

@@ -0,0 +1,53 @@
+package com.github.games647.fastlogin.listener;
+
+import com.github.games647.fastlogin.FastLogin;
+import com.github.games647.fastlogin.PlayerSession;
+import com.github.games647.fastlogin.hooks.AuthPlugin;
+
+import java.util.logging.Level;
+
+import org.bukkit.Bukkit;
+import org.bukkit.entity.Player;
+import org.bukkit.event.EventHandler;
+import org.bukkit.event.Listener;
+import org.bukkit.event.player.PlayerJoinEvent;
+
+public class PlayerListener implements Listener {
+
+    private final FastLogin plugin;
+    private final AuthPlugin authPlugin;
+
+    public PlayerListener(FastLogin plugin, AuthPlugin authPlugin) {
+        this.plugin = plugin;
+        this.authPlugin = authPlugin;
+    }
+
+    @EventHandler(ignoreCancelled = true)
+    public void onJoin(PlayerJoinEvent joinEvent) {
+        final Player player = joinEvent.getPlayer();
+        String address = player.getAddress().toString();
+
+        //removing the session because we now use it
+        PlayerSession session = plugin.getSessions().remove(address);
+        //check if it's the same player as we checked before
+        if (session != null && session.getUsername().equals(player.getName())
+                && session.isVerified()) {
+//            Bukkit.getScheduler().runTaskLater(plugin, () -> {
+//                if (player.isOnline()) {
+//                    plugin.getLogger().log(Level.FINER, "Logging player {0} in", player.getName());
+//                    authPlugin.forceLogin(player);
+//                }
+            Bukkit.getScheduler().runTaskLater(plugin, new Runnable() {
+
+                @Override
+                public void run() {
+                    if (player.isOnline()) {
+                        plugin.getLogger().log(Level.FINE, "Logging player {0} in", player.getName());
+                        authPlugin.forceLogin(player);
+                    }
+                }
+                //Wait before auth plugin initializes the player
+            }, 1 * 20L);
+        }
+    }
+}

src/main/java/com/github/games647/fastlogin/listener/StartPacketListener.java

@@ -0,0 +1,131 @@
+package com.github.games647.fastlogin.listener;
+
+import com.comphenix.protocol.PacketType;
+import com.comphenix.protocol.ProtocolManager;
+import com.comphenix.protocol.events.PacketAdapter;
+import com.comphenix.protocol.events.PacketContainer;
+import com.comphenix.protocol.events.PacketEvent;
+import com.github.games647.fastlogin.FastLogin;
+import com.github.games647.fastlogin.PlayerSession;
+
+import java.io.IOException;
+import java.lang.reflect.InvocationTargetException;
+import java.net.HttpURLConnection;
+import java.security.PublicKey;
+
+import java.util.Random;
+import java.util.logging.Level;
+import java.util.regex.Pattern;
+
+import org.bukkit.entity.Player;
+
+/**
+ * Receiving packet information:
+ * http://wiki.vg/Protocol#Login_Start
+ *
+ * String=Username
+ */
+public class StartPacketListener extends PacketAdapter {
+
+    //only premium (paid account) users have a uuid from there
+    private static final String UUID_LINK = "https://api.mojang.com/users/profiles/minecraft/";
+    //this includes a-zA-Z1-9_
+    private static final String VALID_PLAYERNAME = "^\\w{2,16}$";
+
+    private final ProtocolManager protocolManager;
+    //hides the inherit Plugin plugin field, but we need a more detailed type than just Plugin
+    private final FastLogin plugin;
+
+    //just create a new once on plugin enable
+    private final Random random = new Random();
+    //compile the pattern on plugin enable
+    private final Pattern playernameMatcher = Pattern.compile(VALID_PLAYERNAME);
+
+    public StartPacketListener(FastLogin plugin, ProtocolManager protocolManger) {
+        //run async in order to not block the server, because we make api calls to Mojang
+        super(params(plugin, PacketType.Login.Client.START).optionAsync());
+
+        this.plugin = plugin;
+        this.protocolManager = protocolManger;
+    }
+
+    /**
+     * C->S : Handshake State=2
+     * C->S : Login Start
+     * S->C : Encryption Key Request
+     * (Client Auth)
+     * C->S : Encryption Key Response
+     * (Server Auth, Both enable encryption)
+     * S->C : Login Success (*)
+     *
+     * On offline logins is Login Start followed by Login Success
+     */
+    @Override
+    public void onPacketReceiving(PacketEvent packetEvent) {
+        PacketContainer packet = packetEvent.getPacket();
+        Player player = packetEvent.getPlayer();
+
+        //this includes ip and port. Should be unique for 2 Minutes
+        String sessionKey = player.getAddress().toString();
+
+        //remove old data every time on a new login in order to keep the session only for one person
+        plugin.getSessions().remove(sessionKey);
+
+        String username = packet.getGameProfiles().read(0).getName();
+        plugin.getLogger().log(Level.FINER, "Player {0} with {1} connecting to the server"
+                , new Object[]{sessionKey, username});
+        //do premium login process
+        if (isPremium(username)) {
+            //minecraft server implementation
+            //https://github.com/bergerkiller/CraftSource/blob/master/net.minecraft.server/LoginListener.java#L161
+            sentEncryptionRequest(sessionKey, username, player, packetEvent);
+        }
+    }
+
+    private boolean isPremium(String playerName) {
+        //check if it's a valid playername and the user activated fast logins
+        if (playernameMatcher.matcher(playerName).matches() && plugin.getEnabledPremium().contains(playerName)) {
+            //only make a API call if the name is valid existing mojang account
+            try {
+                HttpURLConnection connection = plugin.getConnection(UUID_LINK + playerName);
+                int responseCode = connection.getResponseCode();
+
+                return responseCode == HttpURLConnection.HTTP_OK;
+                //204 - no content for not found
+            } catch (IOException ex) {
+                plugin.getLogger().log(Level.SEVERE, "Failed to check if player has a paid account", ex);
+            }
+            //this connection doesn't need to be closed. So can make use of keep alive in java
+        }
+
+        return false;
+    }
+
+    private void sentEncryptionRequest(String sessionKey, String username, Player player, PacketEvent packetEvent) {
+        plugin.getLogger().log(Level.FINER, "Player {0} uses a premium username", username);
+        try {
+            /**
+             * Packet Information: http://wiki.vg/Protocol#Encryption_Request
+             *
+             * ServerID="" (String)
+             * key=public server key
+             * verifyToken=random 4 byte array
+             */
+            PacketContainer newPacket = protocolManager
+                    .createPacket(PacketType.Login.Server.ENCRYPTION_BEGIN, true);
+
+            newPacket.getSpecificModifier(PublicKey.class).write(0, plugin.getKeyPair().getPublic());
+            byte[] verifyToken = new byte[4];
+            random.nextBytes(verifyToken);
+            newPacket.getByteArrays().write(0, verifyToken);
+
+            protocolManager.sendServerPacket(player, newPacket, false);
+
+            //cancel only if the player has a paid account otherwise login as normal offline player
+            packetEvent.setCancelled(true);
+            plugin.getSessions().put(sessionKey, new PlayerSession(verifyToken, username));
+        } catch (InvocationTargetException ex) {
+            plugin.getLogger().log(Level.SEVERE, "Cannot send encryption packet. Falling back to normal login", ex);
+        }
+    }
+}

src/main/resources/plugin.yml

@@ -0,0 +1,33 @@
+# project informations for Bukkit in order to register our plugin with all it components
+# ${project.name} are variables from Maven (pom.xml) which will be replaced after the build
+name: ${project.name}
+version: ${project.version}
+main: ${project.groupId}.${project.artifactId}.${project.name}
+
+# meta informations for plugin managers
+authors: [games647, 'https://github.com/games647/FastLogin/graphs/contributors']
+description: |
+    ${project.description}
+website: ${project.url}
+dev-url: ${project.url}
+
+depend: [ProtocolLib]
+softdepend:
+    - xAuth
+    - AuthMe
+    - CrazyLogin
+    - LoginSecurity
+
+commands:
+    premium:
+        description: 'Marks the invoker or the player specified as premium'
+        aliases: [prem, fastlogin, loginfast]
+        usage: /<command> [player]
+        permission: ${project.artifactId}.command.premium
+
+permissions:
+    ${project.artifactId}.command.premium:
+        description: 'Mark themselves as premium using a command'
+        default: true
+    ${project.artifactId}.command.premium.others:
+        description: 'Mark other people as premium'