<p>A &#8220;51% attack&#8221; refers to a malicious scenario in which a single entity or a group of individuals gain control over more than 50% of the total computing power or mining hash rate of a blockchain network.</p>
<p>When a single entity possesses majority control, they can manipulate the decentralized nature of the blockchain and potentially disrupt its operations for personal gain.</p>
<p>With control over the majority, the attacker can prevent new transactions from being confirmed, reverse previously confirmed transactions, and even double-spend cryptocurrencies.</p>
<p>Double-spending involves spending the same cryptocurrency unit more than once, which is a significant concern in a decentralized system.</p>
<p>The attacker may also have the ability to modify or exclude certain transactions from being included in the blockchain, leading to a loss of trust and reliability within the network.</p>
<p>The 51% attack is a serious security threat to blockchain networks, especially those with smaller mining communities or low hashing power.</p>
<p>In order to execute a successful 51% attack, the attacker would require substantial computational resources and control over a majority of the network&#8217;s mining power.</p>
<p>The attack is considered economically irrational for most well-established blockchain networks, as the costs involved in acquiring enough computing power are often prohibitively high.</p>
<p>However, emerging or smaller blockchain networks are more vulnerable to 51% attacks due to their limited resources and lower hash rates.</p>
<p>To mitigate the risk of 51% attacks, blockchain networks often implement consensus mechanisms, such as Proof of Stake (PoS) or Delegated Proof of Stake (DPoS), which rely on different principles than traditional Proof of Work (PoW) to secure the network.</p>


51% Attack

<div class="css-nybri6 etyh6ra0">An economics concept in which one party has a direct advantage in efficiency in producing/providing a specific good or service over another party.</div>


Absolute Advantage

<p>The block header is a section in a block that serves as a summary of the rest of the block. It’s made up of all the metadata – such as the time and difficulty when the block was mined, the Merkle root of the included transactions, and the nonce. Also present is the previous block’s hash, which is what allows us to create the “chain” of blocks. In essence, the block header contains any data that isn’t the list of raw transactions itself.<br />
A block header is what the miners hash to try and make the block valid. This is a lot more efficient than hashing the entirety of the block, which can be made up of thousands of transactions. It would be vastly more cumbersome for a miner to change the nonce and to rehash a whole 2MB block for every attempt. Compare this with hashing Bitcoin’s block headers, for instance, which have a fixed length of 80 bytes.<br />
Block headers are great from a mining point of view, but because of their small size, they’re also ideal for light clients. The Bitcoin blockchain is too large for devices like smartphones to store. If the chain had 100,000 1MB blocks, you’d consume 100GB of space. But with just the block headers for those same blocks, you’d only take up 0.008GB, or 8MB.<br />
In this way, devices with less bandwidth or storage space can still perform some degree of validation. Because the Merkle root encapsulates all of the transactions, they can later check whether a transaction was included in a particular block. This does come at a cost – the user must still rely on a third party to provide them with necessary information. With that said, light clients are preferable to a system where the users perform no verification at all.</p>


Block header

<p>The bid price is the highest price that a particular buyer is willing to pay for a specific product or service. In the context of financial markets, it is the value buyers offer for an asset, such as a commodity, security, or cryptocurrency.<br />
A trading order book consists of multiple bid prices (on the side of buyers) and asking prices (on the side of sellers). The highest bid price is always lower than the lowest asking price and the difference between them is referred to as a bid-ask spread.<br />
Traders or investors that are willing to sell their assets or stock positions need to either accept one of the bid prices available on the order book (ideally, the highest one) or to set an asking price and wait until a buyer eventually bids against that value, filling the order.</p>
<p>In financial markets, traders have the power to decide what price they are willing to buy or sell an asset and they do so at the moment they create their order. Clearly, if the price they set is too far apart from the current market price, their order won’t be filled.</p>
<p>In a situation where multiple buyers are competing for an asset and start putting their bids, one after the other, we would have what is sometimes referred to as a bidding war. When a bidding war occurs, buyers replace their bids higher and higher in order to cover the bids of other competing buyers and this would probably cause the market prices for that asset to increase rapidly.</p>


Bid Price

<p>What Is Bitcoin Pizza?<br />
Bitcoin Pizza refers to the first known purchase of physical goods using bitcoin.<br />
On May 22, 2010, Laszlo Hanyecz, the programmer who would go on to become famous for being the man who bought pizza with bitcoin, made a post on a Bitcoin forum called Bitcointalk. He was looking to make a deal with someone who would take bitcoin as payment for pizza. Hanyecz wrote:<br />
“I’ll pay 10,000 bitcoins for a couple of pizzas.. Like maybe 2 large ones so i have some left over for the next day..”</p>
<p>At the time, 10,000 BTC was equivalent to approximately 41 USD, meaning each bitcoin was worth about 0.0041 USD. Hanyecz’s offer was taken up by another Bitcointalk user, who paid 25 USD for the two pizzas.</p>
<p>Hanyecz acquired the coins by mining on his laptop. Back then, consumer-grade hardware was powerful enough to effectively mine bitcoins. In 2018, Hanyecz used the Bitcoin Lightning Network to buy two pizzas once again, but only spent 0.00649 BTC this time round.<br />
Hanyecz has said in interviews that he doesn&#8217;t regret spending 10,000 BTC on two pizzas. At the time, Bitcoin was an obscure Internet phenomenon followed by only a handful of enthusiasts. Using cryptocurrency to buy a physical good seemed more far-fetched than it does today.<br />
Bitcoin Pizza Day<br />
Thanks to this fabled transaction, May 22 is now known as Bitcoin Pizza Day. It&#8217;s considered a historic moment in the history of bitcoin, marking the first-ever documented time a cryptocurrency was used as a medium of exchange for a real-world purchase.</p>
<p>Today, the 10,000 bitcoins used to purchase those two pizzas would be worth millions of dollars, making it a remarkable example of the early days of bitcoin. The term &#8220;bitcoin pizza&#8221; has even become synonymous with using a cryptocurrency for a seemingly mundane purchase.</p>


Bitcoin Pizza

<p>In short, the term block refers to computer files that store transaction data. These blocks are arranged in a linear sequence that forms an endless chain of blocks &#8211; hence, the term blockchain.<br />
So all information about blockchain transactions is gathered and recorded inside these blocks, and every newly generated block is connected to the previous one through the use of cryptographic techniques.<br />
The chain of linked blocks stores all the transaction data generated since the launch of a particular blockchain. So the records go all the way back to the first block, which is referred to as the block zero or genesis block. The number of confirmed blocks since the genesis block is denoted as the block height.<br />
Taking the Bitcoin blockchain as an example, blocks are made up of multiple elements. Bitcoin blocks contain (among other things) a list of recent transactions, a timestamp, and a reference to the block that came right before it. This reference is a cryptographic hash of the previous block’s data.<br />
The generation of a new block always includes the hash of the previous one, and this is what makes the blocks cryptographically linked. Such a structure allows the creation of a secure database that is highly resistant to tampering and attacks. The block hash acts like an identifier. It is unique to each block and is produced through a process called mining.<br />
Basically speaking, the block hash is the solution to a complex mathematical problem, and the miner that finds a valid solution for the next block is granted the right to validate that block (and the transactions therein). Since mining requires a significant amount of computational resources, successfully mined blocks produce new Bitcoins as a way to reward miners for their work (see block reward).<br />
But sometimes, two or more miners may find a valid block hash at the same time, so that two different blocks are broadcasted to the network. This leads to the creation of two competing chains. To address this problem, the participants of the network (nodes) will choose the chain that eventually becomes the longest (with more “accumulated work”). The other chain is then discarded, and its blocks become stale blocks (see orphan blocks).<br />
Although blocks are usually discussed in the context of cryptocurrency transactions, they may also be related to other types of digital data that are stored on a blockchain system.</p>


Block

<p>Bitcoin Core is the leading implementation of the software enabling users to interact with the Bitcoin network. It is not owned by any single business or organization but is instead updated and reviewed by a community of worldwide developers.<br />
The software was initially released by Satoshi Nakamoto (under the name Bitcoin), only to be later renamed to Bitcoin Core to avoid any confusion.</p>
<p>What does it do?<br />
By running the Bitcoin Core code, a user effectively acts as a node on the network. They can independently verify the validity of blocks received, as well as transactions sent by other users. This keeps miners in check and means that the user needs not trust anyone (such as a wallet provider) to display the correct view of the blockchain.<br />
Bundled into the software is a wallet. Users can use this directly from within the application, or tether external wallets to their node to validate received transactions.</p>
<p>Should I run Bitcoin Core?<br />
Users that frequently transact in Bitcoin should consider running a node to enjoy the various privacy and security benefits. A typical software wallet (one that does not interface with the user’s node) queries third-party servers for the user’s balance.</p>
<p>This practice can be of some concern, as it allows the server to tie the user’s balance to their IP address. The third party can reasonably infer that the user owns the public addresses they ask about.</p>
<p>In a similar vein, total reliance on a block explorer is dangerous from a transparency standpoint. As users have only a single point of reference for their balances, it is easy for the server to transmit false information to them.</p>


Bitcoin Core

<p>In short, Bitcoin is a digital form of money that runs on a distributed network of computers (nodes). In a broader sense, though, many people often use the word Bitcoin to refer to a few different things: a digital currency, a decentralized public ledger, a protocol, or simply the big ecosystem that encompasses all of these. However, there are some fundamental differences between these functionalities.<br />
First, Bitcoin is the name of a peer-to-peer (P2P) digital currency, which is sometimes referred to as bitcoin (with lower “b”) or simply BTC. Bitcoin is a cryptocurrency, which means it is a digital currency that is protected by cryptographic techniques. It was the first cryptocurrency that came into existence, and the first Bitcoin block &#8211; known as the genesis block (or block 0) &#8211; was mined on the 3rd of January 2009.<br />
Second, the Bitcoin decentralized public ledger is what we call blockchain. Despite being closely related, Bitcoin and blockchain are different concepts. The blockchain technology is what maintains the whole structure that allows Bitcoin transactions to be broadcasted and recorded in a trustless and secure way. Note that, in this context, trustless means that the blockchain system does not rely on any kind of trust to function as it is backed by computer code and mathematical algorithms. Thus, the Bitcoin blockchain works as a decentralized digital ledger that publicly lists all confirmed BTC transactions.<br />
Lastly, the term Bitcoin was also used to refer to the protocol that is being continually developed as an open source software. In 2014, however, the original Bitcoin client software was officially rebranded to Bitcoin Core to avoid further misunderstanding. As an open source software, Bitcoin Core counts with numerous contributors worldwide.<br />
Bitcoin was conceptualized by a person (or group) under the pseudonym Satoshi Nakamoto. The idea was to create a unique digital payment system that would permit borderless financial transactions to occur without the need for mediators like banks or governments. The distributed architecture provided by blockchain technology, along with the cryptographic techniques, makes Bitcoin very resistant to attacks and fraud.
</p></div>


Bitcoin

<p>The Beacon Chain is Ethereum’s proof-of-stake (PoS) layer where consensus is reached. It controls and coordinates the network of Ethereum stakers who help validate and secure the network in exchange for staking rewards.<br />
The Beacon Chain went live on December, 2020 and is the first in a series of major upgrades (previously collectively known as Ethereum 2.0) to increase Ethereum’s ability to handle transaction loads more sustainably.<br />
Although the Beacon Chain (previously known as Eth2) is an independent layer that runs parallel to Ethereum’s execution layer (previously known as Eth1), it will soon be connected to the Ethereum mainnet in an event known as The Merge.<br />
Post-merge, Ethereum’s consensus mechanism will permanently shift from proof-of-work (PoW) to PoS. If you are interested in validating the Beacon Chain, you can do so by staking your ether (ETH). As a validator securing the network, you will be in charge of storing data, processing transactions, and adding new blocks to the blockchain.<br />
The ecosystem moving away from mining new blocks means Ethereum miners will eventually become obsolete. Additionally, tokens will no longer be issued in the form of mining rewards, leading to a projected net reduction in ETH issuance of almost 90%.<br />
The Beacon Chain has set the stage for the following scaling solutions: The Merge, The Surge, The Verge, The Purge, and The Splurge. This set of solutions is designed to tackle the Scalability Trilemma proposed by Ethereum founder Vitalik Buterin.<br />
The trilemma suggests that a blockchain can satisfy only two out of three of its fundamental principles — security, scalability, and decentralization. A series of upgrades has been postulated to help Ethereum support a larger transaction load by increasing transaction throughput without compromising security or decentralization.</p>


Beacon Chain

<p>B-Tokens are Binance’s official name for a range of fully-collateralized wrapped tokens. Each B-Token offers a transportable version of an original asset on a different blockchain. Let’s look at a quick example.<br />
Imagine you hold ETH on Ethereum but want to take advantage of staking opportunities on BNB Smart Chain (BSC). You cannot stake your ETH in its current ERC-20 form, so you’ll need to bridge it to BSC with a compatible token standard. To do this, you’ll have to wrap your ETH and, in return, receive a BEP-2 or BEP-20 ETH B-Token that’s BSC compatible.<br />
Binance does this by taking your ETH and securely holding it as collateral. Your B-Token is minted 1:1 with the amount of ETH provided, and you can swap your B-Token back for the underlying collateral at any point, should you wish. This mechanism maintains a stable pegged price for the B-Token towards its underlying ETH collateral.</p>
<p>It’s important to note that B-Tokens are always fully collateralized. You can check our Proof of Collateral for B-Tokens page to see the current state of our B-Token collateral wallets. See our What Are Wrapped Tokens? Binance Academy article for more information on how token wrapping works.</p>


B-Tokens

<p>The portfolio of coins and tokens one is holding. Often related to a poorly performing bag of assets that investors insist to hold.</p>


Bags

<div class="css-nybri6 etyh6ra0">A temporary block created by a mining node (miner) to add to the blockchain to receive the block rewards.</div>


Candidate Block

<div class="css-nybri6 etyh6ra0">A process operating in the background waiting for a specific event or condition in order to be activated.</div>


Daemon

<div class="css-nybri6 etyh6ra0">When the majority of peers on the network are malicious and monopolize the network in order to prevent specific nodes from receiving information from honest nodes.</div>


Eclipse Attack

<p>A situation where a trader enters a position betting on a price movement that quickly reverses or ultimately doesn’t happen.</p>


Fakeout

<div class="css-nybri6 etyh6ra0">The pricing mechanism employed on the Ethereum blockchain to calculate the costs of smart contracts operations and transaction fees.</div>


<p>An individual that has an advanced understanding of computer systems and networks, including programmers and cybersecurity experts.</p>


Hacker

<div class="css-nybri6 etyh6ra0">A conditional order to buy or sell a large amount of assets in smaller predetermined quantities in order to conceal the total order quantity.</div>


Iceberg Order

<p>The smallest denomination of BNB. Derived from the Telegram handle of the Binance Community Manager at the time.</p>


Jager

<div class="css-nybri6 etyh6ra0">A versatile cryptographic function designed by Guido Bertoni, Joan Daemen, Michaël Peeters, and Gilles Van Assche.</div>


Keccak

<div class="css-nybri6 etyh6ra0">The time between submitting a transaction to a network and the first confirmation of acceptance by the network.</div>


Latency

<p>A blockchain protocol which is fully developed and deployed where transactions are being broadcasted, verified, and recorded.</p>


Mainnet

<div class="css-nybri6 etyh6ra0">A participant on a blockchain network that communicates with other participants to ensure the security and integrity of the system.</div>


Node

<div class="sc-bdfBwQ Text-msjfkz-0 byJUJo">Odysee is a server-less video hosting and distribution platform built on top of the LBRY protocol</div>


Odysee

<div class="sc-bdfBwQ Text-msjfkz-0 byJUJo">P2P DEX, or peer-to-peer decentralized exchange, is a blockchain-based application that supports P2P trading.</div>


P2P DEX

<div class="sc-bdfBwQ Text-msjfkz-0 byJUJo">A tool to create and share trading strategies on the FTX exchange.</div>


Quant Zone

<div class="sc-bdfBwQ Text-msjfkz-0 byJUJo">Radio Frequency Identification (RFID) is a type of technology that uses radio waves to passively identify a tagged item or individual.</div>


Radio Frequency Identification (RFID)

<p>A staking pool allows multiple stakeholders (or bagholders) to combine their computational resources as a way to increase their chances of being rewarded. In other words, they unite their staking power in the process of verifying and validating new blocks, so they have a higher probability of earning the block rewards.</p>
<p>The overall idea of the staking pool model is quite similar to the traditional mining pool, which involves the pooling of hash rate in a Proof of Work (PoW) blockchain. However, the staking pool setup is only available on blockchains that employ the Proof of Stake (PoS) model or, in non-POS systems through protocol design features.</p>
<p>Typically, a staking pool is managed by a pool operator and the stakeholders that decide to join the pool have to lock their coins in a specific blockchain address (or wallet). While some pools require users to stake their coins with a third party, there are many other alternatives that allow stakeholders to contribute with their staking power while still holding their coins in a personal wallet. For instance, the so-called cold staking pools enable a more secure model, as users can participate in the staking process while keeping their funds on a hardware wallet.</p>
<p>Compared to solo staking, a staking pool will give smaller rewards because each successful block forging (validation) will split the rewards among the many participants of the pool. In addition, most pools will charge fees, which will reduce even more the final payout. On the other hand, staking pools provide more predictable and frequent staking rewards. Other than that, they allow stakeholders to make a passive income without having to worry about the technical implementation and maintenance of setting up and running a validating node.</p>


Staking Pool

<div class="sc-bdfBwQ Text-msjfkz-0 byJUJo">The Standard and Poor&#8217;s 500, also known as S&amp;P 500, is a stock market index that represents a list of 500 public companies located in the U.S and their performance in the market.</div>


S&P 500 (Standard and Poor’s 500)

<div class="sc-bdfBwQ Text-msjfkz-0 byJUJo">T-addresses are one of the two types of addresses available for the privacy-focused cryptocurrency, Zcash, used when transparency is desired.</div>


T-Address (Zcash)

<div class="sc-bdfBwQ Text-msjfkz-0 byJUJo">Unbanked refers to those that are either unable to access banking services, or choose not to</div>


Unbanked

<div class="sc-bdfBwQ Text-msjfkz-0 byJUJo">A participant on a proof-of-stake (PoS) blockchain, involved in validating blocks for rewards.</div>


Validator

<div class="sc-bdfBwQ Text-msjfkz-0 byJUJo">A place where cryptocurrency users can store, send and receive digital assets.</div>


Wallet

<div class="sc-bdfBwQ Text-msjfkz-0 byJUJo">
<div class="sc-bdfBwQ Text-msjfkz-0 byJUJo">X86 Virtual Machine enables Qtum developers to write smart contracts in a language of their choice.</div>
</div>


X86 Virtual Machine

<div class="sc-bdfBwQ Text-msjfkz-0 byJUJo">The yield curve is a line that plots the relationship between yields and maturities of fixed income securities.</div>


Yield Curve

<div class="sc-bdfBwQ Text-msjfkz-0 byJUJo">Alternative phrasing for an unconfirmed transaction.</div>


CoinUnited Glossary

CoinUnited
Glossary