WAS使用公私钥证书加密解密的问题

开始使用sun的jdk读公私钥证书加密解密，一切正常。换到WAS7后，用私钥加密时报这个错：
Exception in thread "main" java.security.InvalidKeyException: Private key cannot be used to encrypt.
        at com.ibm.crypto.provider.RSA.engineInit(Unknown Source)
        at javax.crypto.Cipher.a(Unknown Source)
        at javax.crypto.Cipher.a(Unknown Source)
        at javax.crypto.Cipher.init(Unknown Source)
        at javax.crypto.Cipher.init(Unknown Source)
        at com.ebank.CrypPara.encryptByPrivateKey(CrypPara.java:146)
        at com.ebank.CrypPara.main(CrypPara.java:51)

baidu后，找到一个办法，就是在ibm网站上下一个无限制文件：Unrestricted SDK JCE policy files 地址：https://www14.software.ibm.com/webapp/iwm/web/preLogin.do?source=jcesdk

下载文件后，将local_policy.jar和US_export_policy.jar更新到jrelibsecurity的文件夹下。

更新后又报了这个错：


Exception in thread "main" java.lang.ExceptionInInitializerError
        at java.lang.J9VMInternals.initialize(J9VMInternals.java:250)
        at javax.crypto.Mac.getInstance(Unknown Source)
        at com.ibm.security.pkcs12.BasicPFX.calculateMac(BasicPFX.java:1905)
        at com.ibm.security.pkcs12.BasicPFX.verifyMac(BasicPFX.java:1165)
        at com.ibm.security.pkcs12.PFX.verifyMac(PFX.java:795)
        at com.ibm.crypto.provider.PKCS12KeyStore.engineLoad(Unknown Source)
        at java.security.KeyStore.load(KeyStore.java:414)
        at com.ebank.CrypPara.initKey(CrypPara.java:120)
        at com.ebank.CrypPara.main(CrypPara.java:50)
Caused by: java.lang.SecurityException: Cannot set up certs for trusted CAs
        at javax.crypto.b.(Unknown Source)
        at java.lang.J9VMInternals.initializeImpl(Native Method)
        at java.lang.J9VMInternals.initialize(J9VMInternals.java:228)
        ... 8 more
Caused by: java.lang.SecurityException: Jurisdiction policy files are not signed by trusted signers!
        at javax.crypto.b.a(Unknown Source)
        at javax.crypto.b.a(Unknown Source)
        at javax.crypto.b.access$600(Unknown Source)
        at javax.crypto.b$0.run(Unknown Source)
        at java.security.AccessController.doPrivileged(AccessController.java:280)
        ... 11 more

请问该如何解决？