code: private static void addProvider(){
  		if (Security.getProvider("BC") == null) {
  			LogUtil.writeLog("add BC provider");
  			Security.addProvider(new org.bouncycastle.jce.provider.BouncyCastleProvider());
  		} else {
  			Security.removeProvider("BC"); //解决eclipse调试时tomcat自动重新加载时，BC存在不明原因异常的问题。
  			Security.addProvider(new org.bouncycastle.jce.provider.BouncyCastleProvider());
  			LogUtil.writeLog("re-add BC provider");
  		}
  		printSysInfo();
  	}
docs: 添加签名，验签，加密算法提供者