There are not many excellent available overviews of blockchain technologies. Thus, when NIST issues a draft “Blockchain Technology Overview,” it is interesting to have a look. It is a 57-page document open for public comments.
I like their description:
Blockchains are distributed digital ledgers of cryptographically signed transactions that are grouped into blocks. Each block is cryptographically linked to the previous one after validation and undergoing a consensus decision. As new blocks are added, older blocks become more difficult to modify. New blocks are replicated across all copies of the ledger within the network, and any conflicts are resolved automatically using established rules.
The document provides a high-level overview of blockchain. There are not many detailed technical descriptions. The document uses the bitcoin structure and vocabulary as all blockchains would use them. Thus, a generic block has necessary a nonce (for the Proof of Work) as well as a Merkle Tree. I am sure that many blockchains will not have such elements. Similarly, it uses the terminology of mining nodes for the validators. For consensus mechanisms that are not Proof of Work, it is not suitable. The sections dedicated to consensus (section 4) and Smart Contracts (section 6) are too light. The golden nugget is section 9: Blockchain Limitations and Misconceptions.
Nevertheless, it is worthwhile to read it and potentially to comment. Knowing the NIST, I am confident that the final document will be a reference document.