Blockchain Technology Study Notes

Definition: Self-executing contracts with the agreement directly written into code.
Functionality: Automatically enforce and execute terms of a contract when predefined conditions are met.
Benefits:
- Efficiency: Reduces the need for intermediaries.
- Transparency: All parties can see the contract terms and execution.
- Trust: Transactions are secure and tamper-proof.
Platforms: Commonly used on Ethereum, Hyperledger, and other blockchain frameworks.

Definition: The incorporation of cryptocurrencies as a medium of exchange within blockchain systems.
Functionality:
- Enables peer-to-peer transactions without intermediaries.
- Utilizes blockchain to record transactions securely and transparently.
Types of Cryptocurrencies:
- Bitcoin: First and most recognized cryptocurrency.
- Altcoins: Variants like Ethereum, Ripple, Litecoin, each with unique features.
Use Cases:
- Payments, remittances, and fundraising through Initial Coin Offerings (ICOs).

Definition: Applications that run on a peer-to-peer network, without a central authority.
Characteristics:
- Open-source: Code is accessible and can be modified by anyone.
- Smart contract integration: Often utilize smart contracts for backend processes.
- Node distribution: Operate on a network of computers, ensuring no single point of failure.
Examples: Financial services (DeFi), games (CryptoKitties), and social networks.

Purpose: Ensure agreement on the state of a blockchain among distributed nodes.
Common Mechanisms:
- Proof of Work (PoW): Requires computational effort to validate transactions (e.g., Bitcoin).
- Proof of Stake (PoS): Validators are chosen based on the number of coins they hold (e.g., Ethereum 2.0).
- Delegated Proof of Stake (DPoS): Stakeholders elect delegates to validate transactions.
- Practical Byzantine Fault Tolerance (PBFT): Allows nodes to reach consensus even if some are faulty or malicious.
Importance: Maintains security, prevents double-spending, and facilitates trust in a decentralized environment.

Security Concerns:
- 51% Attack: If a single entity controls over half the network, it can manipulate transactions.
- Smart Contract Vulnerabilities: Coding errors can lead to exploits or loss of funds.
- Phishing: Users may be tricked into revealing private keys or sensitive information.
Privacy Challenges:
- Transparency vs. Anonymity: Public blockchains expose transaction details while offering pseudonymity.
- Data Protection: GDPR and other regulations challenge how personal data is handled on blockchains.
Solutions:
- Privacy-focused blockchains (e.g., Monero, Zcash) offer enhanced anonymity options.
- Layer 2 solutions (e.g., Lightning Network) can improve transaction privacy and speed.

Self-executing contracts with agreement written into code.
Enforce and execute terms automatically when specific conditions are satisfied.
Benefits include:
- Efficiency by eliminating intermediaries.
- Transparency for all parties in understanding contract terms.
- Enhanced trust due to secure, tamper-proof transactions.
Frequently utilized on platforms like Ethereum and Hyperledger.

Incorporates cryptocurrencies as a medium for blockchain system transactions.
Facilitates peer-to-peer transactions without the need for intermediaries.
Relies on blockchain for secure and transparent transaction recording.
Key types of cryptocurrencies include:
- Bitcoin, the first and most recognized cryptocurrency.
- Altcoins such as Ethereum, Ripple, and Litecoin, each offering unique features.
Use cases encompass payments, remittances, and fundraising via Initial Coin Offerings (ICOs).

Operate on a peer-to-peer network without a central authority.
Characteristics include:
- Open-source code, available for public modification.
- Integration of smart contracts for backend functionality.
- Node distribution across multiple computers to avoid single points of failure.
Examples include decentralized finance (DeFi), gaming applications like CryptoKitties, and social networking platforms.

Purpose is to attain agreement among distributed nodes on blockchain state.
Common mechanisms feature:
- Proof of Work (PoW): Requires significant computational power for transaction validation (e.g., Bitcoin).
- Proof of Stake (PoS): Validators selected based on the number of coins held (e.g., Ethereum 2.0).
- Delegated Proof of Stake (DPoS): Stakeholders elect representatives for transaction validation.
- Practical Byzantine Fault Tolerance (PBFT): Achieves consensus even with faulty or malicious nodes.
Importance lies in maintaining security, preventing double-spending, and fostering trust in decentralized setups.

Notable security concerns include:
- 51% Attack: A single entity controlling over half the network can manipulate transactions.
- Smart Contract Vulnerabilities: Coding flaws can lead to exploits or loss of assets.
- Phishing Attacks: Users may be deceived into disclosing private keys or sensitive information.
Privacy challenges arise from:
- Transparency of public blockchains exposing transaction details contrasted with pseudonymity.
- Data protection regulations like GDPR pose challenges for handling personal data on blockchains.
Potential solutions include:
- Privacy-focused blockchains, such as Monero and Zcash, which provide heightened anonymity.
- Layer 2 solutions like the Lightning Network to enhance transaction privacy and speed.