PPTP: PPTP by itself doesn’t provide dataencryption, but it has supports multi protocol VPNs with 40 bit or 128 bit. It usesMicrosoft point-to-point encryption.

L2TP: it provides the security of IPsecover tunneling of tunneling protocol. Right now Internet Service Provider also can provide L2TP to their dial-in users.

Data tunneling: means using tunneling toadd another layer 3 address to hide the original ip that produces the data. In somecases, it could be a issue, like in some websites it doesn’t allow some particularIPs from some specific countries, so now you need tunneling protocol to hideyour real IP to access in the websites.

Data integrity: it is important to verify the data hasn’t been changed during the transit.

Data authentication: it is also important to verify the identity of the source that sends the data.

Anti replay: this function is to detect there played data that might be from spoofing with bad means.

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BLOCKCHAIN

Cryptocurrency has a “production” role for compensating miners asrewards when they successfully win validating transactions.

It also has a consumption role as paying a small for running smartcontract or a transaction fee on Ripples or Bitcoins.

Token also can be used as a unit of interval values.

Its just like currencies, but it has a friction whenever every time itis into real world of traditional currency.

Software infrastructure.

Blockchain is like well-designed software, powered by servers as ifthey are bound together to operate but physically located around the world, andwhat is really amazing is the developers don’t need to set up these servers.

As contrasted with web where HTTP request is sent to server, withblockchain apps, the network makes request to blockchain.

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Tunneling requires 3 protocols

Passenger:Original data

Encapsulating protocol

Carrier protocol

For site-to-site VPNs, the encapsulating protocol are usually IPsec and Generic Routing Protocol.

For remote access VPNs, usually use PPP protocol, part of TCP/IP stack, point-to-point protocol.

Authentication, authorization and Accounting. Used for more secure access, a validate username and passwords are required. They can be stored in device itself or AAA external server which can provide authentication to other databases such as Window NT, Novell, LDAP and so on. 

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Blockchain can be a transaction platform, capable of handlingmicrotransactions and largely value transactions. It can validate transactionsthat have been digitized and later verified that these transactions have takenplace. They are recorded as a “block” which is a storage space.

Blockchain’s TPS(transaction per second) is far less than current VisaNet or PayPal, but people are looking forwarding increasing TPS on the blockchain in the future.

Blockchain is like a decentralized database, it will shatter database and change the way

people see it. The author has asserted since 2014 that blockchain is going to

be the trend and developer