The rules for Bitcoin were established in the beginning, cannot be changed
There is a single, known inflation rate
There are strict rules for sending money around
Full Nodes
Transactions happen on Bitcoin in the form of blocks
Full nodes decide to accept blocks based on a set of rules
All full nodes have the same set of rules
Nodes with different rules are a different currency!
Bitcoin's Rules, Simplified
Some people have money
Money can be sent from one person to another
Once you send the money, it no longer belongs to you
Nobody can stop you from sending money
Bitcoin's Rules, Simplified
People who 'mine' blocks get Bitcoins
This is where inflation comes from
25 Bitcoin reward for mining a block
1 block every 10 minutes - enforced by the node rules
Illegal blocks will be ignored by the network
Full Nodes Repeated
Full nodes accept blocks
Chains of blocks form the history
Full nodes will ignore illegal blocks
Every full node has the same exact definition of 'illegal'
Nodes with a different definition of illegal diverge from the network - a different, isolated & worthless currency
Miners in Bitcoin
Miners create blocks
All blocks must follow the rules
Blocks that don't follow the rules are worthless
Miner's don't enforce the rules, they build consensus
Double Spending
I send the same $10 to two people, Alice and Bob
Who has the $10?
Miners decide who gets the $10
Double Spending
Miners put transactions into blocks
Transactions are not allowed to conflict
Blocks build upon eachother in a chain
Multiple Histories
There can be multiple orderings of blocks
Different orderings are called 'Forks'
One ordering might say 'Alice got my $10', and another might say 'Bob got my $10'
Which Ordering is Real?
The ordering that has the most 'work'
The Towers Example
There are two towers. One says 'Alice got $10', one says 'Bob got $10'. Who has $10?
The tallest tower wins!
It's hard to build a tower, but easy to see which tower is tallest
The Towers Example
People are paid to build on the tallest tower.
People don't get paid if they build on a smaller tower
Everyone tries to build on the tallest tower
One tower eventually definitely wins
Mining is Tower Building
Blocks are like stones building a tower
Miners get paid only if their block is in the longest chain
When two competing chains appear, one will definitely win
Then, everybody knows who got the $10.
This is Why Bitcoin is Special
Anyone can verify the true history by just seeing the towers!
Largest legal tower wins! (illegal towers are ignored)
There is no trust!
Why Does This Matter?
You can't be cheated
You don't need to go to court
If you have money, and it's got work on top of it, that money is definitely yours.
My Bitcoin Savings
I have some Bitcoins saved
They have over 50,000 blocks on top of them
Theft requires rebuilding 50,000 blocks - $500 Million of Work!
They are safe
My Bitcoin Savings
No bank can steal my bitcoins
There is no inflation on my bitcoins
I can spend my bitcoins anywhere that accepts bitcoins (no capital controls)
And All you Need is the Internet and a Computer
An Internet connection + a computer is enough for you to have your own bitcoin wallet
When someone sends you bitcoins, they are irreversibly yours
No strings attached!
Q & A
Bitcoin in the Real World
Bitcoin is Really Powerful
Bitcoin can be used in areas where there are no banks
Bitcoin can be used by merchants to minimize chargeback risk
Bitcoin can be used to send money across borders
Bitcoin is Good and Bad
Like all powerful technology, it can be used for good and for evil
In the early days of Bitcoin, it was mostly used for evil
Today, it is mostly used for good
More Good than Bad
Bitcoin is empowering remittances
Bitcoin is enabling bankless regions
Many of the bitcoin criminals have been caught
Don't make Bitcoin illegal - traditional criminal investigation can be used to catch Bitcoin criminals
Bitcoin's Value Restated
Blockchains allow you to interact safely with people you don't trust.
Irreversibility
A transaction that is confirmed on Bitcoin cannot be reversed
This is great if you are receiving money
This is bad if someone is stealing your money
With Power Comes Responsibility
Bitcoin lets you be your own bank
If you get robbed, you are to blame
Nobody can get your coins back, no matter who they are
No FDIC Insurance
Securing Bitcoins
Run a full node
Keep a cold wallet
Use a hardware wallet
Full Nodes
Validate all of the rules
Full nodes are heavy, most wallets are not full nodes
Anything less has a significantly reduced security model - trusts miners, or worse trusts an centralized entity such as Blockchain.info or Coinbase
Cold Wallets
Wallets have private keys
Without the keys, you can't spend the coins
Cold wallets are not connected to the internet - you can't hack into a computer that's offline.
Hardware Wallets
Special hardware to keep keys secure
Basically, an advanced cold wallet
Keys inside the wallet never escape - you can only spend the bitcoins if you have the physical hardware wallet.
Web Wallets
Bitcoins held by a third party
Third party has full control
Insecure, they can steal. Same as a bank.
Brain Wallets
Memorized password that can be used to generate keys
Can be used anywhere, very convenient
Very insecure!
Convenient/okay for small amounts of money
Scalability
Bitcoin can handle 1MB every 10 minutes
This number may go up, but it won't go up by much
Currently about 3tps, one day maybe 300tps
VISA does 50,000tps at peak times
Bitcoin Doesn't Scale
Today: Send money anywhere in the world for 6 cents
Next Year: Probably several dollars
Bitcoin is cheap today, will be expensive in the future
Can't scale because we lose trustlessness
For Big Purchases, Scale is Not Needed
We can't support every transaction on the Bitcoin blockchain
Buying houses is more important than buying coffee
Bitcoin cannot support most coffee purchases
Bitcoin can support most Big purchases
Bitcoin is Good for Savings
Can't be seized
Will not inflate
Useful all over the world
Bitcoin is Good for Savings
It's not as important to decentralize your small payments as it is to decentralize your savings and your big payments
Q & A
Innovations on top of Bitcoin
Lightning Network
Cutting edge, unfinished technology that enables small payments on Bitcoin
Operates by trustlessly cramming a ton of payments into a single transaction
Still not complete, needs more time
Altcoins
Simple Altcoins - Litecoin, Dogecoin, etc. - not very valuable to ecosystem
Advanced Altcoins - Ethereum, Sia, etc. - highly experimental, very risky, but provide lots of knowledge
Alternate Consensus Systems - Peercoin, Ripple, MaidSAFE, etc. - generally considered insecure
Private Blockchains
Reintroduce the need for trust
Often useful, but suboptimal
Generally missing the point of the technology, but again can be useful even if unnecessarily clunky (simpler systems serve the same goals)
Don't Make Your Own
DANGER
Just because it works, does not mean that it is secure
Anyone can design something they don't know how to break. But someone smarter than you may know how to break it
Don't make your own
Bitcoin was made by dozens of experts. Even dozens of experts got a lot of things wrong. This stuff is HARD, innovation should happen through groups of experts
People Lose Money
Bitcoin is particularly bad, because there is often a money prize for taking advantage of a broken system
Security concerns means that innovation is slow, but the tech is powerful so that's okay.
Bitcoin Is The Future
Trustless finance will change the way we look at money
Bitcoin is going to be reshaping the world, and rapidly
It's worth investigating further. My talk has only scratched the surface