Blockchain and Crypto Essentials Flashcards
Year that blockchain was established?
2009 (first BTC was mined)
How to confirm transaction in double entry ledger accounting?
Confirm on the ledgers of the two businesses, a credit to one and a debit to the other.
What is consensus?
The mechanism and rules by which nodes agree on the validitity of the past and current blockchain as well as the process of how new txs/info can be added
What is blockchain (block definition)?
A series of chronological snapshots of an updated ledger containing information that is secured with cryptography.
How crypto address is created?
Produced by using a hash function on the public key along with information about the network (depending on the blockchain)
Point of public key encryption vs digital signing
Public key encryption: to secure a message itself
Digital signing: to securely determine the point of origin
Each block has a unique number called what?
Height
Process for a proof-of-work transaction
- Transaction is signed with Sally’s private key and sent.
- A node on the network receives the transaction and verifies the sender’s funds, then places it in the mempool.
- The miner gathers transactions from the mempool, verifies each sender’s funds and signature, and places them together into a potential block.
- Miner then searches for a special hash with leading zeroes by changing the nonce (random number, “number only once”), running computation, repeating until result is a valid hash and block (hash must be below difficulty number).
- The miner then sends valid block to a node, which also checks the block and its transactions, then distributes it to other nodes. Processed tx’s are removed from the mempool.
Blockchain interoperability meaning
Separate blockchains being able to interact with each other
What is the Ethereum Foundation?
Basically supports further research and development for Ethereum
How public key is created?
Mathematically derived from the private key using a complex algorithm
Ethereum established when?
Crowdsourcing campaign - 2014
Ethereum Blockchain launched - 2015
How often is the bitcoin mining difficulty adjusted?
Every 2,016 blocks (~2 weeks)
Wallets hold what?
Private keys associated with a public key address, not actual coins/tokens
Year of first paper outlining blockchain
1991
What is triple ledger accounting?
With an established blockchain, companies can each maintain their own business ledgers, but transactions can also be recorded on the distributed blockchain.
Cryptography definition
Practice and study of techniques (like encryption and decryption) for secure communication
How data is encrypted
Using an algorithm, also called a cipher.
How cryptographic hash functions work?
Takes input string of digital data (numbers, letters, images, videos, ebooks) of any size and uses an algorithm to transform it into a fixed-length result, called a hash or digest.
What does it mean that cryptographic hash functions are irreversible?
Attackers cannot reverse engineer a hash to figure out the original inputs.
How proof-of-stake works
Users of a network stake their shares of the network’s currency to become validators, which then are chosen at random to create blocks based on the agreed-upon rules.
When not creating new blocks, validators are responsible for checking and confirming new blocks (called “attesting”).
What does Ethereum offer beyond Bitcoin?
Bitcoin: currency and ledger (record of transactions)
Ethereum: can be programmed and run computation
How cryptography scrambles a message
Put it through an algorithm before sending. Only ones who can read it are those who know the algorithm.
What does it mean that cryptographic hash functions are deterministic?
The same inputs will always yield the same output
How much computational power needed for cryptographic hash functions?
The functions are fast with low computational overhead.
Are digitally signed messages secure/confidential?
No, anyone on the network can see the message using the public key. However, this process does prove that the message is authentic and unaltered.
Primary purpose of a block
To record transactions
Example of Consortium blockchain
3 companies and government regulator operate nodes, where all 4 entities must sign transactions, and where all can access and audit the ledger without needing access to internal ledgers of the other entities. Also, public not able to see these tx’s.
Difference between coin and token?
Ethereum and Bitcoin native currencies are coins (ETH and BTC)
Apps built on top of them would be tokens.
Function of private keys in a wallet?
Allows one to prove ownership of coins in a network
Advantage of triple ledger accounting
Can make the process of auditing complicated transactions much easier, as it doesn’t require coordinating the separate books from many different business entities.
Cryptographic hash function type of output?
Hexadecimal number
What is a hexadecimal number?
Also called base 16, a number that contains 16 symbols per numeral column, 0–9 and A-F.
Types of blockchains
Public, Consortium (shared permissioned), and Private (permissioned)
Bitcoin’s key innovation
Enabling participants to digitally transact directly with each other without relying on a single, centralized intermediary, such as a bank, to validate the payments.
Three forms of decentralization coined by Vitalik Buterin
Architectural (de)centralization
Political (de)centralization
Logical (de)centralization
Greek meaning of cryptography
Hidden writing. It’s as old as the earliest messages we ever wrote using codes or cipher.
What does “SHA-256” stand for and what is it?
Secure Hashing Algorithm, with a hash length of 256 bits, used by the Bitcoin blockchain
What is the miner reward/subsidy?
The reward for finding the correct hash for the new block and establishing it, in the form of some of the blockchain’s tokens and transaction fees
Way for any network node to confirm a newly mined block
Hash the information and nonce in the new block themself and ensure that it’s below the difficulty setting
Term for programs that can be deployed on Ethereum blockchain
Decentralized applications (dApps) or smart contracts
What is a distributed ledger?
Multiple copies of the ledger distributed on a network, so there is no one authoritative copy. There are specific rules around updating them.
What is tokenization?
Creating on-chain representation of one or multiple assets in the form of a token.
This can be everything from physical objects to ideas to a bundle of existing blockchain tokens.
Why is the BTC mining difficulty adjusted periodically?
To keep the block time at 10 minutes (600 seconds)
How is validity related to the difficulty setting?
The difficulty setting determines how low the hash must be of a newly mined block to be valid.
Any block mined with a higher hash would be considered invalid and not accepted by other nodes
Ether (ETH) token allows users what?
The ability to pay for transactions or computing power on the Ethereum blockchain.
How is information in Blockchains immutable (permanent)?
After blocks are created and accepted by the network, any change to a previous block would change the current block’s hash, which would not be tolerated by the participants.
How much ETH will users need to stake to become a validator?
32 ETH
What is a ledger?
A book of transactions, recording debits and credits
What does it mean that collision is very unlikely with cryptographic hash functions?
Different inputs into the hash function are extremely unlikely to ever produce the same result.
What is a network’s hashrate or hashpower?
A key security metric showing the hashing (computing) power in the network by its miners.
Higher computing power means that it is more resistant to attacks because of the expense that would have to be incurred.
Current bitcoin block reward/subsidy
6.25 BTC
What does it mean that traditional Internet structure is server-based?
anyone who wants to interact with an online service must connect to the same server
Where are the coins/tokens stored of each networks’ users?
On the blockchain network itself, not a wallet. Technically, no account balances are actually stored, just transaction information, which is a list of credits and debits going all way back to the genesis block.
Goal of decentralization
Shift power and authority in a community away from one central entity and make it available to the members themselves, making community members self-sovereign
What are tokens?
Representations of value or the permission to do some actions within an application.
For example, a token could represent an opportunity to play a video game or download a song.
In public key cryptography, private and public keys can encrypt and decrypt what?
Each key can encrypt a message but not decrypt one it encrypted. Each can decrypt a message that was encrypted by its corresponding key.
Difference between encryption and hashing
Encrypted items are meant to also be decrypted, so they are two-way.
Hashing is only one-way, so once the output data has been generated, the hash cannot be reversed to find the input.
How blocks in the Blockchain are linked together?
On each new block, the previous block’s hash is included, then hashed into the new block’s hash.
In proof-of-work chains, how do nodes agree on what makes a block valid?
If the correct hash is produced, as this shows commitment to the system because significant work was done to mine the new hash and create the block.
Simplified Payment Verification (SPV)
Enables someone running a light client to verify that a transaction has been included in a blockchain and therefore a payment has been made.
Year that the concept of Proof-of-Work established
1993 initial paper
What is the Mining Difficulty?
A setting that determines how hard it is to create blocks. The higher the difficulty, the lower the mined block’s hash must be, and the more work it takes to mine (thus proof of the work).
Without a difficulty setting, the first mined/hashed block would be accepted, defeating the purpose of the proof-of-work concept.
Types of nodes
Full nodes store of the entire blockchain and verify every block and transaction.
Light nodes store a recent portion of the blockchain and also verify blocks and transactions.
Difference between Web 1.0, 2.0, 3.0
- 0 information being available
- 0 interaction with info and other users
- 0 user interaction with ownership of their information and networks?
What is Ciphertext?
Scrambled text that results from encryption performed on plain text.
Hashing algorithm used by Ethereum blockchain
Keccak-256
Nonce purpose
A block data field used by miners that can be changed with each computation to find the correct and valid block hash.
Year that all 21 million bitcoin will be distributed
2140
Encryption definition
In cryptography, it is the process of encoding information
Why decentralized networks can be more secure
Not a central system to attack.
A decentralized network consists of many nodes and can function if individual nodes go down because others are still active
Process of digitally signing?
Sender
- Take a hash of message/data
- Encrypt that hash with sender’s private key
- Send msg/data and encrypted hash to recipient
Recipient
- Decrypt encrypted hash with sender’s public key.
- Take a hash of the msg/data received
- Compare this hash to decrypted hash from sender to verify authentic and unaltered from sender
Bitcoin blocks contain how many transactions?
Generally around 1,500-2,000, depending on block size limits
Node definition
A computer connected to a blockchain network that is responsible for its maintenance and security.
Usually stores a copy of the blockchain and ensures its validity.
What is a smart contract?
- Lines of code stored at a specific blockchain address. executed by machines on a blockchain.
- They instruct data when and how it should move.
What is the Enterprise Ethereum Alliance (EEA)?
A non-profit created to connect entities with Ethereum subject experts, in order to lead to Ethereum’s further adoption.
Bitcoin current block size limit
One megabyte
Drawbacks of proof-of-work
- Uses large amounts of energy
- Transaction rates and volumes are lower
- Transaction fees are higher to pay for power use
How proof-of-stake validators can lose stake?
By attesting to, or validating, malicious blocks
What is an unspent transaction output (UTXO)?
The amount of cryptocurrency that remains after a transaction is executed
How is the total gas cost calculated on Ethereum?
Amount of gas needed for the computation times the current gas price
What parts of blockchains are forkable?
All code, dApps, and smart contracts
If a flash loan is not repaid with required interest by the end of the transaction, what happens?
It reverts to the state before any money left the lender’s account and everything resets as if the user had not borrowed money.
Price of gas on Ethereum dependent on what?
Network use/congestion
What is a keeper?
A type of EOA (externally owned accont) that receives a fee to perform an action in a DeFi protocol or other dApp
Ethereum EOA accounts have ability to do what?
(Human account) Initiate transactions, receive, hold and send tokens, and interact with deployed smart contracts
What is a slashing (negative) incentive?
The removal of a portion of a user’s staked balance as the result of an undesirable event.
What is a “slashing condition”?
A mechanism that triggers a slashing
On an AMM, original trading pair and market price: 1 Eth = 100 DAI. Formula (xy=k) with 10 of ea in liquidity pool is 101,000=10,000
If new market price outside of this exchange is 1 Eth = 400 DAI, how does trading pair/liquidity pool change?
The pricing of the pair on this exchange would move to reflect market prices.
Dai would be sold to get Eth, resulting in the new pool looking like: 5*2,000=10,000, so 1 Eth = 400 DAI
How Bitcoin transactions and UTXOs work?
Accounts consist of balances of UTXOs. If Bob is sending 2 BTC to John and Bob has a UTXO of 10, 5, and 3 in their account, they might use the 3 for the transaction, spending an output of 2 to John, with the remaining 1 being another new output that comes back to Bob.
Ethereum gas measurement unit?
Gwei, which is one billionth of one ether
Why quantum computing irrelevant to crypto?
Public and private keys can be changed to use quantum resistant signatures.
Irrelevant to consensus mechanisms, even PoW because it’s still whoever can find the correct hash fastest.
Two forms of burning tokens?
- Manually send a token to an unowned Ethereum address.
2. More efficient is to create a contract that is incapable of spending them
What are some other applications where consensus is needed when there is not one leader?
Jury (unanimous consensus)
Senate (majority consensus)
What does it mean that the EVM is a Turing Complete machine?
It can run computation and programs that any other normal computer can
Fungible meaning?
Mutually interchangeable; able to replace or be replaced by another identical item
Swapping on a decentralized exchange is considered what and what?
Atomic and non-custodial
Why mint tokens?
Incentivize a wide range of behavior (supply liquidity, encourage use of a platform)
Entering a liquidity pool and acquiring corresponding ownership share.
How is a bonding curve deployed?
It can be a single smart contract with options for purchasing and selling the underlying token.
If a person deposits 15 ETH with a market value of $200/unit in a MakerDAO vault and the collateralization requirement is 150%, how much DAI can they borrow against the deposit?
The equivalent of 10 ETH or $2,000 in DAI.
If ea ETH market value is $200, then $3000/1.5 = $2,000 or 2,000 DAI can be minted/borrowed.