Introduction to Blockchain and Ethereum

Editor's Notes

• #16: Blockchains don’t actually eliminate trust. What they do is minimize the amount of trust required from any single actor in the system. They do this by distributing trust among different actors in the system via an economic game that incentivizes actors to cooperate with the rules defined by the protocol.
• #19: The term "Colored Coins" loosely describes a class of methods for representing and managing real world assets on top of the Bitcoin Blockchain. While originally designed to be a currency, Bitcoin's scripting language allows to store small amounts of metadata on the blockchain, which can be used to represent asset manipulation instructions.
• #24: DNS Solidity: https://ethfiddle.com/Vw97YA5xgE
• #25: Externally owned accounts, which are controlled by private keys and have no code associated with them. Contract accounts, which are controlled by their contract code and have code associated with them nonce: If the account is an externally owned account, this number represents the number of transactions sent from the account’s address. If the account is a contract account, the nonce is the number of contracts created by the account. balance: The number of Wei owned by this address. There are 1e+18 Wei per Ether. codeHash: The hash of the EVM (Ethereum Virtual Machine — more on this later) code of this account. For contract accounts, this is the code that gets hashed and stored as the codeHash. For externally owned accounts, the codeHash field is the hash of the empty string. storageRoot: A hash of the root node of a Merkle Patricia tree (we’ll explain Merkle trees later on). This tree encodes the hash of the storage contents of this account, and is empty by default.
• #26: https://youtu.be/mCzyDLanA7s Elliptic Curve Digital Signature Algorithm
• #27: Any kind of cost that happens in Ethereum gets translated to gas. Similarly to how in bitcoin fees get translated in some amount of bitcoin per transaction byte, same applies here Imposing fees prevents users from overtaxing the network. Ethereum is a Turing complete language. (In short, a Turing machine is a machine that can simulate any computer algorithm (for those not familiar with Turing machines, check out this and this). This allows for loops and makes Ethereum susceptible to the halting problem, a problem in which you cannot determine whether or not a program will run infinitely. If there were no fees, a malicious actor could easily try to disrupt the network by executing an infinite loop within a transaction, without any repercussions. Thus, fees protect the network from deliberate attacks. https://medium.com/@preethikasireddy/how-does-ethereum-work-anyway-22d1df506369
• #31: Demo with Jaxx and Metamask What you need is th eprivate key, because this is what allows you to open … Οπως στις τραπεζικες θυριδες, τα λεφτα ειναι παντα εκει, ωστοσο χρειαζεσαι το κλειδι για να τα μετακινήσεις
• #33: Programming and interacting with smart contracts