How do new members join the blockchain

nick_ching23

Hi everyone, I am new to HLF

I just wanted to know - how can you ensure that new members joining the Blockchain are genuine - assuming that you didn't know fully who you were interacting with. Would it be possible to add in some automated requirements to be granted permission to join? Like a digital certificate used to identify that online sites are secure?

I would really appreciate some clarification on this topic!