NISTIR 8202 provides a high-level overview of blockchain technology. Blockchain is a tamper-evident and tamper-resistant digital ledger implemented in a distributed manner, without a central repository or authority. At its core, it enables a community of users to record transactions in a shared ledger, ensuring that once a transaction is published, it cannot be altered. The document explains how blockchain technology works, focusing on its use in cryptocurrencies like Bitcoin, where transactions are digitally signed and recorded publicly. It discusses the components of blockchain, including cryptographic hash functions, transactions, asymmetric-key cryptography, addresses, ledgers, and blocks. It also covers consensus models such as proof of work, proof of stake, and round robin, as well as the concept of forking, which involves modifying the blockchain. The document highlights the use of smart contracts and addresses limitations and misconceptions of blockchain technology. It emphasizes the importance of understanding the technology's fundamentals, including its distributed nature, cryptographic security, and shared ledger system. The document also discusses the differences between permissionless and permissioned blockchain networks, and provides guidance on how organizations can apply blockchain technology appropriately. It concludes with a summary of the key aspects of blockchain technology, including its potential applications, challenges, and considerations for implementation.NISTIR 8202 provides a high-level overview of blockchain technology. Blockchain is a tamper-evident and tamper-resistant digital ledger implemented in a distributed manner, without a central repository or authority. At its core, it enables a community of users to record transactions in a shared ledger, ensuring that once a transaction is published, it cannot be altered. The document explains how blockchain technology works, focusing on its use in cryptocurrencies like Bitcoin, where transactions are digitally signed and recorded publicly. It discusses the components of blockchain, including cryptographic hash functions, transactions, asymmetric-key cryptography, addresses, ledgers, and blocks. It also covers consensus models such as proof of work, proof of stake, and round robin, as well as the concept of forking, which involves modifying the blockchain. The document highlights the use of smart contracts and addresses limitations and misconceptions of blockchain technology. It emphasizes the importance of understanding the technology's fundamentals, including its distributed nature, cryptographic security, and shared ledger system. The document also discusses the differences between permissionless and permissioned blockchain networks, and provides guidance on how organizations can apply blockchain technology appropriately. It concludes with a summary of the key aspects of blockchain technology, including its potential applications, challenges, and considerations for implementation.