Cryptocurrency is defined as a group of binary data that acts as a medium of exchange, or currency. Cryptocurrencies are usually fiat currencies, as they are not backed by, or convertible into, a commodity like gold. Cryptocurrency transactions are verified and recorded by a decentralized system that uses cryptography, rather than by a centralized authority like a bank.
Most cryptocurrencies are built to run on blockchains. Blockchains are records of cryptocurrency transactions made up of individual "blocks" that are formed with each transaction and linked together with cryptography. Blocks are all tied to and built off of the previous blocks behind it, which reinforces the chain it creates. Each block is made up of a cryptographic hash of the last block, a date and timestamp, and other data related to the transaction the block is referencing. Blocks and blockchains are very difficult, but not impossible, to modify due to each block's ties to the next: any data alteration affects every other subsequent block in the chain.
Base layer protocols are the peer-to-peer networks which form the basis of the Decentralized application (dApp) web. These base protocols are typically blockchains with an associated cryptocurrency coin secured by a consensus protocol where participants in the network decide collectively on the addition of new blocks to the blockchain ledger.
Fundamental concepts related to blockchains.
- Smart contracts
- Digital ledger
- Game theory
- Medium of exchange
- Cryptographic hash function
Properties of blockchains and cryptocurrency systems.
- Blockchain decentralization
- Blockchain security
- Blockchain scalability
- Blockchain interoperability
- Node peer discovery
Components of blockchains.
- Cryptographic nonce
- Merkle tree
- Digital signatures
- Cryptographic hash function
- Public key cryptography
Consensus algorithms, sybil control mechanisms, and other topics related to consensus mechanisms for establishing a consistent canonical agreement between network participants on the blockchain state.
Sybil control mechanisms
- Proof-of-Work (PoW)
- Proof-of-Stake (PoS)
- Proof-of-Capacity (PoC)
- Proof-of-Burn (PoB)
- Proof of Proof-of-Work (PoPoW)
- Proof-of-Authority (PoA)
- Proof-of-Activity (PoA)
- Proof-of-Storage (PoS)
- Proof-of-Replication (PoRep)
- Proof-of-Time (PoT)
- Delegated Proof-of-Stake (DPoS)
- Proof-of-Stake-Velocity (PoSV)
- Leased Proof-of-Stake (LPoS)
- Proof-of-Resource (PoR)
- Proof-of-Importance (PoI)
- Proof-of-Provenance (PoP)
- Proof-of-Devotion (PoD)
- Proof-of-Believability (PoB)
- Proof-of-Audit (PoA)
- Sentinel Proof of Retrievability (SPoR)
- 2D Byzantine Delegated Proof-of-Stake (2D-BPoS)
- Proof of Elapsed Time (PoET)
- Proof-of-Stake Voting (PoSV)
- Proof of Replica (PoR)
- Proof of Storage and Time (PoST)
- Proof-of-Service (PoS)
- Proof-of-Signature (PoSign)
- Proof of Involvement and Integrity (PII)
- Proof of Stake & Trust (PoST)
- Randomized Delegated Proof of Stake (Roll-DPoS)
- Proof of Trust (PoT)
- Proof of View (PoV)
- Proof-of-Consumption (PoCon)
- Proof-of-Transaction (PoT)
- Proof of Creativity (PoC)
- Proof of Contribution (PoC)
- Proof of Attention (PoA)
- Proof of Lock (PoL)
- Loop Fault Tolerance
- Mediated Consensus
- Random Beacon
- MimbleWimble protocol
- Dandelion protocol
- See-Saw rewards mechanism
Methods by which malicious actors can attempt to subvert or disrupt the intended functionality of blockchain protocols.
- 51 percent attack (majority attack)
- Sybil attack
- Block withholding attack
- Selfish Mining attack (Block discarding)
- Long range attack
- Cryptographic dust
Cryptocurrencies with the primary intention of a decentralized currency replacement to traditional fiat currencies by being a store of value, a unit of account, or a medium of exchange.
Platforms for decentralized applications allowing for the execution of code on the blockchain in the form of smart contracts. These platforms allow for more generalized logic to be coded on the blockchain enabling a broad range of Web 3.0 decentralized applications.
A specialized form of cryptocurrencies focused on maintaining the privacy and anonymity of individuals transaction with them.
A class of distributed ledgers whose structure does not rely blocks of transactions but rather other architectures like a directed acyclic graph. These alternate ledgers have different security, scalability, and consensus properties from blockchain technologies.
Blockchains or distributed ledgers that require special access or permission to participate rather than being open to the public.
Infrastructure comprises the development stack for building decentralized applications. These are protocols and tools that may connect and support applications and other protocols in a variety of ways.
Interoperability protocols allow for communication of state, data, or value transfer between different blockchains.
Store and retrieve files and data without relying on a trusted central authority.
Decentralized database projects.
Projects focusing on both on-chain and off-chain solutions for increasing blockchain transaction throughput.
Privacy and security projects for decentralized applications.
Tools which help developers create and secure smart contract code.
Programming languages that are specific to smart contracts, i.e. contract-oriented programming languages.
Blockchain oracles are a blockchain technology that allows blockchains or smart contracts to interact with external data sources. Prediction market blockchains focus on bringing traditional prediction markets to the blockchain.
Projects restructuring the way that institutions, political systems, and people govern and organize themselves using blockchain or decentralized technologies.
Projects with decentralized governance or providing support for managing organizations through decentralized governance.
Connecting decentralized systems into traditional legal frameworks.
Projects working towards a more open and user controlled Internet.
Decentralized VPN services.
Projects creating marketplaces or frameworks for peer to peer value exchange without a centralized intermediary. Projects in these categories often have what are considered utility tokens, which represent future access to a service.
Advertising platforms connecting users, advertisers, and publishers directly without ad network intermediaries.
Protocols enabling the sharing and monetization of data resources.
Projects building decentralized marketplaces.
Projects working on decentralized mesh networks.
Decentralized social networks, communication tools, and social related applications built using blockchain technology. These projects employ a variety of differentiators from traditional social networks involving data privacy, monetary incentives, and more.
Projects working on decentralized content monetization platforms enabling content creators and content consumers to transaction directly without third party mediation.
Decentralized projects in which users provide computation in exchange for tokens.
Projects focusing on the redistribution, transmission, and retail of energy via decentralized systems.
Decentralized property and housing rental.
Decentralized ride sharing.
Projects related to decentralized storage of genomic data and marketplaces for the exchange of genetic information.
The field of decentralized finance and cryptocurrency investments.
Centralized exchanges for cryptocurrencies trading.
A decentralized cryptocurrency exchange is an exchange market that utilizes blockchain or another decentralized technology to enable peer to peer transfer of digital assets without reliance on a trusted third party to hold funds usually supported by liquidity providers.
Services that help individuals make payments.
Tools and projects assisting the trading and exchange between cryptocurrencies.
Platforms for managing cryptocurrency investments.
Wallets are the user interface for directly interacting with the blockchain to transfer and move cryptocurrencies. Both hardware and software are included.
Cryptocurrency hedge funds and venture firms are investment funds which pool capital from investors into a group of assets focusing entirely or partially on cryptocurrencies or other decentralized digital assets. Hedge funds and venture funds typically have different incentive structures, with hedge funds being focused on shorter timeframes and venture firms on longer timeframes.
Projects working on credit, risk, and lending.
Decentralized peer to peer insurance.
Platforms for issuing and exchanging tokenized securities.
Debit cards for spending cryptocurrencies.
Platforms to manage and launch blockchain crowdfunding projects.
Stablecoins are projects attempting to create decentralized cryptocurrencies with specific properties like low volatility and non reliance on centralized backing.
Crypto-collectibles are digital collectibles, commonly using the ERC-721 non-fungible Ethereum token standard, recorded on a blockchain ledger.
Other types of cryptocurrency and blockchain related projects.
Securing data records on immutable ledger systems.
Companies consulting on blockchain and smart contract technologies.
Cryptocurrencies as video game virtual assets, or other projects related to entertainment and gaming.
Decentralized projects aiming to link the Internet of things to decentralized blockchain technology.
Blockchains & Distributed Ledger Technologies
Introduction to Permissioned Blockchains
June 2, 2019
Permissioned blockchain | Examples | Public, Private, Permissioned Blockchains Compared
Documentaries, videos and podcasts
- BlockchainA blockchain is an append-only digital ledger storing a set of time-ordered transactions grouped in blocks that are linked together using cryptographic hashes.
- CryptocurrencyA cryptocurrency (or crypto currency) is a digital asset designed to work as a medium of exchange using cryptography to secure the transactions and to control the creation of additional units of the currency. Cryptocurrencies are a subset of alternative currencies, or specifically of digital currencies.
- CryptographyCryptography or cryptology is the practice and study of techniques for secure communication in the presence of third parties.
- BitcoinBitcoin is a cryptocurrency and a digital payment system invented by an unknown programmer, or a group of programmers, under the name Satoshi Nakamoto. It was released as open-source software in 2009.
- EthereumEthereum is an open-source, public, distributed blockchain computing platform featuring smart contract (scripting) functionality, which facilitates online contractual agreements.
- Non-fungible token (NFT)Non-fungible tokens are specialized types of cryptographic tokens that represent something unique or rare.
- Vitalik ButerinVitalik Buterin is a Russian-Canadian computer scientist, programmer, writer, and founder of Ethereum.
- Satoshi NakamotoPseudonym for the person or group who designed and developed bitcoin
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