my minecraft crash!@

[14:47:58] [Client thread/INFO]: Setting user: TheKingShoko
[14:47:58] [Client thread/INFO]: (Session ID is token: :ec2ce0bf8d92315a909c3eafb667c915)
[14:47:59] [Client thread/INFO]: LWJGL Version: 2.9.1
[14:48:02] [Client thread/INFO]: Reloading ResourceManager: Default
[14:48:03] [Client Shutdown Thread/INFO]: Stopping server
2015-11-28 14:48:05,180 WARN Unable to register shutdown hook due to JVM state
[14:48:05] [Sound Library Loader/INFO]: Starting up SoundSystem...
[14:48:05] [Thread-9/INFO]: Initializing LWJGL OpenAL
[14:48:05] [Thread-9/INFO]: (The LWJGL binding of OpenAL.  For more information, see http://www.lwjgl.org)
[14:48:05] [Thread-9/INFO]: OpenAL initialized.
[14:48:05] [Sound Library Loader/INFO]: Sound engine started
[14:48:22] [Client thread/INFO]: Created: 512x512 textures-atlas
javax.crypto.BadPaddingException: Decryption error
	at sun.security.rsa.RSAPadding.unpadV15(Unknown Source)
	at sun.security.rsa.RSAPadding.unpad(Unknown Source)
	at com.sun.crypto.provider.RSACipher.doFinal(RSACipher.java:363)
	at com.sun.crypto.provider.RSACipher.engineDoFinal(RSACipher.java:389)
	at javax.crypto.Cipher.doFinal(Cipher.java:2165)
	at tk.wurst_client.alts.Encryption.loadKeys(Encryption.java:217)
	at tk.wurst_client.alts.Encryption.checkKeys(Encryption.java:93)
	at tk.wurst_client.alts.Encryption.encrypt(Encryption.java:56)
	at tk.wurst_client.files.FileManager.saveAlts(FileManager.java:410)
	at tk.wurst_client.files.FileManager.init(FileManager.java:90)
	at tk.wurst_client.WurstClient.startClient(WurstClient.java:61)
	at net.minecraft.client.Minecraft.startGame(Minecraft.java:528)
	at net.minecraft.client.Minecraft.run(Minecraft.java:359)
	at net.minecraft.client.main.Main.main(Main.java:129)
java.lang.NullPointerException
	at tk.wurst_client.alts.Encryption.encrypt(Encryption.java:61)
	at tk.wurst_client.files.FileManager.saveAlts(FileManager.java:410)
	at tk.wurst_client.files.FileManager.init(FileManager.java:90)
	at tk.wurst_client.WurstClient.startClient(WurstClient.java:61)
	at net.minecraft.client.Minecraft.startGame(Minecraft.java:528)
	at net.minecraft.client.Minecraft.run(Minecraft.java:359)
	at net.minecraft.client.main.Main.main(Main.java:129)
java.lang.NullPointerException
	at tk.wurst_client.files.FileManager.saveAlts(FileManager.java:411)
	at tk.wurst_client.files.FileManager.init(FileManager.java:90)
	at tk.wurst_client.WurstClient.startClient(WurstClient.java:61)
	at net.minecraft.client.Minecraft.startGame(Minecraft.java:528)
	at net.minecraft.client.Minecraft.run(Minecraft.java:359)
	at net.minecraft.client.main.Main.main(Main.java:129)
java.lang.NullPointerException
	at tk.wurst_client.files.FileManager.loadSliders(FileManager.java:383)
	at tk.wurst_client.gui.GuiManager.setup(GuiManager.java:222)
	at tk.wurst_client.WurstClient.startClient(WurstClient.java:63)
	at net.minecraft.client.Minecraft.startGame(Minecraft.java:528)
	at net.minecraft.client.Minecraft.run(Minecraft.java:359)
	at net.minecraft.client.main.Main.main(Main.java:129)
[14:48:25] [Client thread/INFO]: No update found.