# Coin.AI: A Proof-of-Useful-Work Scheme for Blockchain-based Distributed Deep Learning

arXiv: https://arxiv.org/abs/1903.09800 · HTML: https://mlsanity.com/paper/1903.09800/

## Key facts

- Cited by 10 papers in the map (data through 14 Oct 2026).
- First posted on arXiv 23 Mar 2019.

## Built on by (most cited first, 10 of 10)

- [Proof-of-Learning with Incentive Security](https://mlsanity.com/paper/2404.09005/) (2024)
- [AI-Based Crypto Tokens: The Illusion of Decentralized AI?](https://mlsanity.com/paper/2505.07828/) (2025)
- [Can Blockchains Reliably Train Machine Learning Models?](https://mlsanity.com/paper/2307.07066/) (2023)
- [Web3 Meets AI Marketplace: Exploring Opportunities, Analyzing Challenges, and Suggesting Solutions](https://mlsanity.com/paper/2310.19099/) (2023)
- [Proof of Useful Intelligence (PoUI): Blockchain Consensus Beyond Energy Waste](https://mlsanity.com/paper/2504.17539/) (2025)
- [A Collaboration Strategy in the Mining Pool for Proof-of-Neural-Architecture Consensus](https://mlsanity.com/paper/2206.07089/) (2022)
- [Byzantine-Resilient Learning Beyond Gradients: Distributing Evolutionary Search](https://mlsanity.com/paper/2304.13540/) (2023)
- [Proof of Deep Learning: Approaches, Challenges, and Future Directions](https://mlsanity.com/paper/2308.16730/) (2023)
- [SEDULity: A Proof-of-Learning Framework for Distributed and Secure Blockchains with Efficient Useful Work](https://mlsanity.com/paper/2512.13666/) (2025)
- [HadAgent: Harness-Aware Decentralized Agentic AI Serving with Proof-of-Inference Blockchain Consensus](https://mlsanity.com/paper/2604.18614/) (2026)

## Abstract (arXiv)

One decade ago, Bitcoin was introduced, becoming the first cryptocurrency and establishing the concept of "blockchain" as a distributed ledger. As of today, there are many different implementations of cryptocurrencies working over a blockchain, with different approaches and philosophies. However, many of them share one common feature: they require proof-of-work to support the generation of blocks (mining) and, eventually, the generation of money. This proof-of-work scheme often consists in the resolution of a cryptography problem, most commonly breaking a hash value, which can only be achieved through brute-force. The main drawback of proof-of-work is that it requires ridiculously large amounts of energy which do not have any useful outcome beyond supporting the currency. In this paper, we present a theoretical proposal that introduces a proof-of-useful-work scheme to support a cryptocurrency running over a blockchain, which we named Coin.AI. In this system, the mining scheme requires training deep learning models, and a block is only mined when the performance of such model exceeds a threshold. The distributed system allows for nodes to verify the models delivered by miners in an easy way (certainly much more efficiently than the mining process itself), determining when a block is to be generated. Additionally, this paper presents a proof-of-storage scheme for rewarding users that provide storage for the deep learning models, as well as a theoretical dissertation on how the mechanics of the system could be articulated with the ultimate goal of democratizing access to artificial intelligence.