# Smart Contracts
A unit of programmable logic that is stored on a [blockchain](blockchain.md) and executed as part of a [consensus-algorithm](consensus-algorithm.md). Despite the namesake smart contracts have little if anything to do legal contracts as defined in standard Common Law. Smart contracts are simply programs which mediate the exchange of [crypto asset](cryptoasset.md) on a [blockchain](blockchain.md) network as part of a programmed prescription and which [wallet](wallet.md) actions can execute specific actions.

## Oracle Problem
Since blockchain networks are self-contained, unlike with a normal computer program, there is no way for a smart contract to "pull" or fetch data from the public internet. Instead data has to be "pushed" into so-called *oracle contracts* which act as information services that provide external "real-world" data to contracts.

This fundamentally introduces a trust boundary issue as smart contracts then need to depend on a trusted thirty party data vendor and undermines the idealized form of [decentralization](decentralization.md) that allegedly underpins the design and purpose of [smart contracts](smart-contracts.md).

## Examples
* [NFT](nft.md)
* [DAO](dao.md)
* [ICO](ico.md)
* [AMM](amm.md)
* [DEX](dex.md)
* ERC20
* [Mixer](mixer.md)

## References
1. Mik, Eliza. 2017. ‘Smart Contracts: Terminology, Technical Limitations and Real World Complexity’. Law, Innovation and Technology 9 (2): 269–300. https://doi.org/10.1080/17579961.2017.1378468.
1. Ante, Lennart. 2020. ‘Smart Contracts on the Blockchain – A Bibliometric Analysis and Review’. SSRN Electronic Journal, no. 10: 1–48. https://doi.org/10.2139/ssrn.3576393.
1. Barbosa, Leonardo Peixoto. 2021. ‘Blockchain Smart Contracts: A Socio-Legal Approach’. European Business Law Review 32 (2). https://kluwerlawonline.com/journalarticle/European+Business+Law+Review/32.2/EULR2021010.
1. Caldarelli, Giulio. 2020. ‘Understanding the Blockchain Oracle Problem: A Call for Action’. Information (Switzerland) 11 (11): 1–19. https://doi.org/10.3390/info11110509.
1. Jason Kolber, Adam. 2018. ‘Not-So-Smart Blockchain Contracts and Artificial Responsibility’. Stanford Technology Law Review 21 (2): 198–234. https://law.stanford.edu/publications/not-so-smart-blockchain-contracts-and-artificial-responsibility/.
1. Pinna, Andrea, Simona Ibba, Gavina Baralla, Roberto Tonelli, and Michele Marchesi. 2019. ‘A Massive Analysis of Ethereum Smart Contracts Empirical Study and Code Metrics’. IEEE Access 7: 78194–213.