Coin Desk blockchain general
Brave New Coin
Oleg Andreev

This is the e-book that accompanies David's talk on blockchain: 

CLICK HERE for the Siegel Blockchain E-Book

David Siegel's Glossary (definition of smart contracts at the end)

Ethereum Browser
A browser that includes a wallet and your trust network, so when you see apps, you see names and data rather than encrypted numbers. Your browser is essentially loaded with cash, so you can make transactions easily.

The first online decentralised currency, powered by its own blockchain. Currently at $6b market cap. 

A common ledger that thousands of computers create simultaneously. It prevents double-spending and rewriting, thus it is maintained accurately and can’t be hacked. It scales easily, as all transactions carry small payments that power the network. 

Blockchain viewer
Software that lets you see the current block being built and query the chain. 

The rules require a majority of nodes to agree to each new block. Anyone who wants to force a change would need to control 51% of nodes. 

Distributed apps
Applications that use smart contracts to move assets on the chain. They are run by all network nodes and can’t be stopped prematurely. 

Distributed ledger
A file that records transactions and may carry payloads, like smart contracts or content. All nodes in the network maintain an exact replica of the ledger, which is made up of blocks “chained” together with special hyperlinks. 

An open-source system that executes smart contracts on its own blockchain. Ethereum nodes can execute all smart contracts and maintain a copy of the Ethereum blockchain.

The native token of the Ethereum network. Is now the second-largest digital currency by market cap, behind Bitcoin. 

Small amounts of money charged by and paid to people who run nodes, which power the network.

A way to encrypt content that creates a numerical representation of a fixed length (often 156 characters). Hashing is beyond the scope of this web site - it is for technical people who use it throughout the decentralised ecosystem to preserve anonymity and ensure authenticity. 

Private key
The number (usually 30+ digits) that can unlock a transfer of ownership of an on-chain asset. People who have high-value on-chain assets must carefully guard their keys to make sure they are not stolen or lost. 

Public key
The other “half” of the encryption scheme. You give your public key to anyone to create a message (using a hash) that only you can decrypt. This is how blockchain nodes recordyour account information, so you can claim ownership of it later. Everyone can see this key and know how much value is in the account, but your identity is not public.

Units of value or score keeping within a single system. Examples are poker chips, airline miles, game points, mobile minutes.

Triple Ledger
Stores a “from,” “to,” and “amount” for each entry, denominated in the currency of the blockchain it’s on. Currently, you can’t mix currencies inside a single blockchain. 

All actors are untrusted. Because the blockchain is compiled and maintained by a large number of people who do it for the money, they can’t collude and steal your assets, the system can’t be hijacked, and only you have the keys to unlock your data. 

A wallet stores private keys. May be hot (online) or cold (held offline in memory that doesn’t rely on electricity). Don't lose your private keys!

Smart Contracts

A smart contract is software that runs on every computer in the Ethereum network. It is “on chain” code. 

It is unambiguous, can transfer asset ownership, and the results are recorded onto the blockchain by all nodes in the network. 

It may be made up of sub-contracts and have unknown dependencies. It cannot be revoked except according to predetermined conditions.

The software will execute as written regardless of any legal frameworks. 

Because smart contracts are networked code, they are not private. In most cases, this is a good thing. Groups are working on creating libraries of code/contract modules that will form an active “smart” infrastructure that eventually will tie into smart legislation and existing legal frameworks worldwide.

Rather than drafting a costly, lengthy contract using attorneys, banks, notaries and Microsoft Word, contracts might be created with a few lines of code, perhaps constructed automatically by wiring together a handful of human readable clauses.

Contracts that are both executable and human readable are called Ricardian contracts.