Name: IOTA的糾結--簡單的解釋 (IOTA's Tangle - Simply Explained)
Uploaded: 2021-01-14T07:45:23.000Z
Duration: 5 min 36 s
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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

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

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

“Directed” means 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

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

These are called “edges” and they validate
the transactions.

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

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.

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

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

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

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

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

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.

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

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.

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.

Usually miners are there to create blocks
and validate transactions.

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

Sending money around is this completely free!

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

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!