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  • When Bitcoin was first released to the world in 2008 it started a revolution.

  • People claimed that the blockchain would solve many problems and that it has countless of

  • applications.

  • Blockchains indeed have very interesting properties and you can learn all about them in this video

  • here.

  • However they have one big limitation and that is that don't scale very well.

  • This is exactly the problem that the creators of IOTA wanted to solve.

  • Instead of using a blockchain, IOTA uses something called a DAG or tangle.

  • DAG is short for Directed Acyclic Graph and it's a storage system where individual items

  • link to each other.

  • Directedmeans that the link between items always have a direction and acyclic

  • means that you cannot create loops inside this structure.

  • This might sound complicated, so let's take a look at a simple tangle.

  • Each square represents a single transaction and is also called a “site”.

  • Each site contains all the details about the transaction: such as the sender, the receiver

  • and the amount of coins.

  • It also has a connection to at least two other transactions.

  • These are callededgesand they validate the transactions.

  • Here is an example of a bigger Tangle.

  • Near the end of our Tangle we find a few transactions that don't have two or more incoming edges.

  • This means that these transactions are unconfirmed.

  • We also call these the tips of the tangle.

  • Alright now that we understand some of the IOTA terminology, let's take a look at how

  • we can add a new transaction to the tangle.

  • We have to attach our new transaction to one of the tips of the tangle.

  • An algorithm selects two of them at random and makes sure that the transactions don't

  • conflict with one another.

  • If one of the tips is a fake transaction, it is ignored and a new tip is selected.

  • If everything checks out, we attach our transaction to the two tips.

  • This adds our transaction to the tangle and verifies the two other transactions.

  • Our transaction is now part of the tangle and becomes a new tip.

  • This technique makes IOTA's tangle incredibly scalable.

  • For every transaction that is added to the tangle, two others are being confirmed.

  • This means that the network doesn't slow down when there are a lot of new transactions.

  • In fact, it actually speeds up!

  • That's all great, but how do we know we can trust a transaction?

  • In traditional blockchains people often use the number of confirmations to check wether

  • or not a block should be trusted.

  • Well IOTA has similar technique.

  • Each site has a weight.

  • This number signifies the amount of work that a node has done to make this transaction.

  • In other words: a higher number means the node spent more time doing the proof-of-work

  • for that transaction.

  • Each transaction also has a cumulative weight.

  • This is the sum of it's own weight plus the sum of the weights of all transactions

  • that approve this transaction.

  • It seems quite complicated, but it really isn't.

  • Here is an example of a Tangle where every transaction has a weight of 1.

  • We'll put the weight of an individual transaction in the bottom right of each square.

  • Now let's check how trustworthy this pink transaction is by calculating its cumulative

  • weight.

  • To do that, we sum up the weight of the two transactions that have approved it.

  • But those transactions where approved by other transaction as well.

  • So we keep summing up all these weights until we get to the end of the tangle.

  • In this case, the accumulative weight of the site is 6.

  • Transactions with a high cumulative weight are usually older and have more direct or

  • indirect verifications.

  • So we can trust those transactions more then others.

  • So now you know what IOTA's tangle is and how works.

  • But how does it stack up against traditional blockchains?

  • Well, the tangle solves two big issue's: scalability and miners.

  • Let's discuss _scalability_.

  • As we've seen: IOTA's network becomes faster when more transactions happen.

  • This means that IOTA can handle almost an unlimited amount of transactions per second

  • while traditional blockchains can only handle a few.

  • But there is an other aspect to scalability that most people seem to forget and that is

  • storage.

  • In a blockchain, you need a full copy of the chain before you can start adding new transactions.

  • Right now the Bitcoin blockchain is almost 150GB in size and keeps growing very fast.

  • Storing all this data is not something every device can do and will get harder over time.

  • IOTA's Tangle is much more lightweight.

  • You don't need a full copy of the tangle to add transactions.

  • You only need a small part of the tangle to create and verify transactions.

  • This makes it much more future proof.

  • And finally IOTA has _no miners_.

  • Usually miners are there to create blocks and validate transactions.

  • For this hard work, miners take a fee from each transaction.

  • In IOTA, no miners means no fees.

  • Sending money around is this completely free!

  • So now you know how IOTA's tangle works, and how it compares to regular blockchain

  • technology.

  • If you liked this video, please give it a thumbs up and get subscribed to my channel.

  • Thank you very much for watching, and I'll see you in the next video!

When Bitcoin was first released to the world in 2008 it started a revolution.

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IOTAのもつれ - 簡単に説明します。 (IOTA's Tangle - Simply Explained)

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    Yi-Cheng Guo に公開 2021 年 01 月 14 日
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