diff --git a/LaunchServer/source/LaunchServer.java b/LaunchServer/source/LaunchServer.java
index ddbf113..b6ab303 100644
--- a/LaunchServer/source/LaunchServer.java
+++ b/LaunchServer/source/LaunchServer.java
@@ -510,7 +510,9 @@
 			if (url.isEmpty()) {
 				return null;
 			}
-			return CommonHelper.replace(url, "username", username, "uuid", uuid.toString(), "hash", ClientLauncher.toHash(uuid));
+			return CommonHelper.replace(url, "username", IOHelper.urlEncode(username),
+				"uuid", IOHelper.urlEncode(uuid.toString()),
+				"hash", IOHelper.urlEncode(ClientLauncher.toHash(uuid)));
 		}
 	}
 }
diff --git a/LaunchServer/source/auth/provider/URLAuthProvider.java b/LaunchServer/source/auth/provider/URLAuthProvider.java
index e0d3b94..8cbcba2 100644
--- a/LaunchServer/source/auth/provider/URLAuthProvider.java
+++ b/LaunchServer/source/auth/provider/URLAuthProvider.java
@@ -39,6 +39,6 @@
 	}
 
 	private String getFormattedURL(String login, String password) {
-		return CommonHelper.replace(url, "login", login, "password", password);
+		return CommonHelper.replace(url, "login", IOHelper.urlEncode(login), "password", IOHelper.urlEncode(password));
 	}
 }
diff --git a/LaunchServer/source/command/hash/DownloadAssetCommand.java b/LaunchServer/source/command/hash/DownloadAssetCommand.java
index 1a463cc..5242820 100644
--- a/LaunchServer/source/command/hash/DownloadAssetCommand.java
+++ b/LaunchServer/source/command/hash/DownloadAssetCommand.java
@@ -44,7 +44,7 @@
 
 		// Download required asset
 		LogHelper.subInfo("Downloading asset, it may take some time");
-		unpack(new URL(String.format(ASSET_URL_MASK, version.name)), assetDir);
+		unpack(new URL(String.format(ASSET_URL_MASK, IOHelper.urlEncode(version.name))), assetDir);
 
 		// Finished
 		server.syncUpdatesDir(Collections.singleton(dirName));
diff --git a/LaunchServer/source/command/hash/DownloadClientCommand.java b/LaunchServer/source/command/hash/DownloadClientCommand.java
index 2240d0a..5f792c1 100644
--- a/LaunchServer/source/command/hash/DownloadClientCommand.java
+++ b/LaunchServer/source/command/hash/DownloadClientCommand.java
@@ -48,7 +48,8 @@
 
 		// Download required client
 		LogHelper.subInfo("Downloading client, it may take some time");
-		DownloadAssetCommand.unpack(new URL(String.format(CLIENT_URL_MASK, version.name)), clientDir);
+		DownloadAssetCommand.unpack(new URL(String.format(CLIENT_URL_MASK,
+			IOHelper.urlEncode(version.name))), clientDir);
 
 		// Create profile file
 		LogHelper.subInfo("Creaing profile file: '%s'", dirName);
@@ -59,7 +60,8 @@
 		}
 		client.setTitle(dirName);
 		client.block.getEntry("dir", StringConfigEntry.class).setValue(dirName);
-		try (BufferedWriter writer = IOHelper.newWriter(IOHelper.resolveIncremental(LaunchServer.PROFILES_DIR, dirName, "cfg"))) {
+		try (BufferedWriter writer = IOHelper.newWriter(IOHelper.resolveIncremental(LaunchServer.PROFILES_DIR,
+			dirName, "cfg"))) {
 			TextConfigWriter.write(client.block, writer, true);
 		}
 
diff --git a/LauncherAuthlib/source/yggdrasil/LegacyBridge.java b/LauncherAuthlib/source/yggdrasil/LegacyBridge.java
index e7558b0..e4c6bb7 100644
--- a/LauncherAuthlib/source/yggdrasil/LegacyBridge.java
+++ b/LauncherAuthlib/source/yggdrasil/LegacyBridge.java
@@ -2,6 +2,7 @@
 
 import launcher.client.ClientLauncher;
 import launcher.helper.CommonHelper;
+import launcher.helper.IOHelper;
 import launcher.helper.LogHelper;
 import launcher.request.auth.CheckServerRequest;
 import launcher.request.auth.JoinServerRequest;
@@ -20,14 +21,14 @@
 	public static String getCloakURL(String username) {
 		LogHelper.debug("LegacyBridge.getCloakURL: '%s'", username);
 		return CommonHelper.replace(System.getProperty("launcher.legacy.cloaksURL",
-			"http://skins.minecraft.net/MinecraftCloaks/%username%.png"), "username", username);
+			"http://skins.minecraft.net/MinecraftCloaks/%username%.png"), "username", IOHelper.urlEncode(username));
 	}
 
 	@SuppressWarnings("unused")
 	public static String getSkinURL(String username) {
 		LogHelper.debug("LegacyBridge.getSkinURL: '%s'", username);
 		return CommonHelper.replace(System.getProperty("launcher.legacy.skinsURL",
-			"http://skins.minecraft.net/MinecraftSkins/%username%.png"), "username", username);
+			"http://skins.minecraft.net/MinecraftSkins/%username%.png"), "username", IOHelper.urlEncode(username));
 	}
 
 	@SuppressWarnings("unused")