Java.security.InvalidKeyException: Illegal key size or default parameters error

Error message
->Illegal key size or default parameters  
->at javax.crypto.Cipher.checkCryptoPerm(Cipher.java:1011)  
->at javax.crypto.Cipher.implInit(Cipher.java:786)  
->at javax.crypto.Cipher.chooseProvider(Cipher.java:849)
->at javax.crypto.Cipher.init(Cipher.java:1213)  
->at javax.crypto.Cipher.init(Cipher.java:1153)
解決方法:
->我的JDK版本是jdk1.7.0_17
->下載:Java Cryptography Extension (JCE) Unlimited Strength Jurisdiction Policy Files 7
->下載網址:http://www.oracle.com/technetwork/java/javase/downloads/jce-7-download-432124.html
->把local_policy和US_export_policy這兩個檔案放在C:\Program Files (x86)\Java\jre7\lib\security