When a tunnel comes to be established froma dial-up client, the VPN prompts an username and password. This can beauthenticated locally or to external AAA server.
Prompt: when you prompt someone to do something, you make them decide to do it.
Nonrepudiation: this feature is highly desirable when it comes to a financial transaction. It can prevent user from denying taking participate in a financial transaction. It works by attaching a digital signature to the sent message, thus to preclude user from denying to have taken part in this transaction.
Repudiate: to disagree strongly with something and not want to be connected with.
=====================================================================
Linear: a linear process is like a line which progresses or processes from one stage to another. It has the starting point and ending point.
So the blockchain is like a space that you can store anything you like, anyone can verify that you’ve placed the information because there is your signature on it. But only you who have the private key can unblock the information.
Adimittedly, blockchain is not a very efficient software. But that’s OK. Because that’s the job of the developer to figure out how to rewrite it to take advantage of the blockchain.