due the network design , can't launch jenkins slave by ssh , so we lanuch jenkins slave by java web start and have enabled the ssl connection from jenkins slave to jenkins master by below doc
https://github.com/hughperkins/howto-jenkins-ssl

when we run jenkins job, it include the credential that used in CURL call, jenkins master send these credential to jenkins slave by plain model

so is there a way to secure the connection from jenkins master to jenkins slave?