a 21e8 project


Pricing Primitive

21e8 is a special metaprotocol on top of bitcoin that facilitates cryptographic pricing of any piece of information, providing an alternative to today’s big tech recommender models and a protection against shilling attacks[1]. Bridging information content and attention with proof of work opens the potential for true information supply chains for software, media and more. We call these new ecosystems computational data markets because they combine real-time content creation with distributed data exchange.

The Primitive

21e8 uses sha256 based proof of work to encode a specific protocol magic number into a content hash alongside any number of extra proofs of work. this enables both a category and a value signal to be embedded into a content id, which influences how it is placed and routed through distributed hash tables. hot data can be routed by networking and storage nodes according to a costly signal embedded into the checksum. this provides a production-side alternative to consumer-side adwords/pagerank, and other recommendation systems


When retrieving content, simply filter for the magic number you want to look for and then sort data by recently published proofs of work.

To promote content, simply take any checksum - whether it's a file, a public key, or a transaction id, select the magic number you want to bias for, target an amount of proof of work, and publish the resulting hash to the network.

For an example implementation, check out bit.sv, a bitcoin based content market, where content can be promoted and feedback can be posted using magic numbers which correspond to emojis in the proof of work.

Sample Code

Use Cases

Search Market

Instead of relying on a central service provider to crawl, index and order the results of a search query, a query can be distributed to multiple search service providers who must compete with each other for user attention.

Content Ordering

Social networks like Twitter and Facebook rely on recommender algorithms to filter and promote content to optimise engagement. 21e8 can be used by decentralised social networks to enable content to be reordered in a deterministic fashion, removing the need for a centralised training system and ad market to determine the relative value of different pieces of content.

Social Pricing

21e8 enables social participation of user bases in determining what content gets shown based not just on personal preferences but market value. New social apps, games and exchanges can be created to facilitate creation, optimisation and distribution of content.

Functions as a Service

The 21e8 protocol bridges data-centric, compute-centric, and user-centric resource constraints by enabling different algorithms to have a computational complexity cost estimate. Tradeoffs in program structure (serial or parallel), cache management and memory allocation all benefit from the ability to model the useful output of a program versus its simple operating costs. By highlighting high value computations, prioritisation of optimisation effort becomes much easier, as does understanding when you've reached diminishing returns.

Community Links

21e8miner - Bitcoin Script Pubkey Puzzle and JavaScript miner by Dean Little

Faster miner by RelayKing

bit.sv - Marketplace for content with native support for 21e8 mining puzzles by Brad Jasper

pow.market - Tracker for 21e8 jobs on Bitcoin by Brad Jasper

boostPoW - ASIC compatible implementation for #000..0 magic numbers by Daniel Krawisz

jsminer - uses secp256k1-node_fast_unsafe and bitsocket to prioritise jobs.


[1] Zhou W, Wen J, Qu Q, Zeng J, Cheng T (2018) Shilling attack detection for recommender systems based on credibility of group users and rating time series. PLOS ONE 13(5): e0196533. https://doi.org/10.1371/journal.pone.0196533

[2] Back, Adam. "Hashcash-a denial of service counter-measure." (2002). http://www.hashcash.org/papers/hashcash.pdf

[3] Finney, Hal. "Reusable proofs of work (rpow)." (2004). http://web.archive.org/web/20071222072154/http://rpow.net/

[4] Nakamoto, Satoshi. "Bitcoin: A Peer-to-Peer Electronic Cash System" (2008) https://bitcoin.org/bitcoin.pdf.