# Blockchain: Current Challenges and Future Prospects/Applications
## 5 Disruptive Blockchain Applications
### Smart Contracts  
Smart contracts are probably the blockchain technology with the highest potential to affect, or even revolutionize, all sorts of transactions from the execution of legal agreements to the IoT. Smart contracts encapsulate algorithmic code that is served by a peer-to-peer network. For example, a smart contract can be instantiated to algorithmically enforce the terms of an agreement without the need for a traditional legal document. In such cases, smart contracts allow the performance of transactions without lawyers or notaries. The transactions are trackable and irreversible and do not require courts and judges to be enforced. Consider for example, the executor of a will who approves the directives of the deceased on how the money will be spent/allocated and his/her assets distributed. Instead of an executor, a programmable, legally binding smart contract can achieve the same purpose, using blockchain technology and avoiding any intermediary. Doing so would certainly reduce costsand improve efficiency. The Chainlink [[https://chain.link/](https://chain.link/)]([https://chain.link/](https://chain.link/)) network enables smart contracts in various networks for existing applications and external data, sending payments postulated in the smart contract to designated bank accounts, and creating secure cross-chain connectivity between the smart contract and other public or private parties. An additional application of smart contracts is where the IoT facilitates the sharing of services and resources, leading to the creation of a decentralized marketplace of services between devices and people that would allow us to automate, in a cryptographically verifiable manner, time-consuming work flows, and interactions (see [33]). The following is a non-exhaustive list of major platforms with smart-contract capabilities:  
_Ethereum_[[https://www.ethereum.org/use/](https://www.ethereum.org/use/)]([https://www.ethereum.org/use/](https://www.ethereum.org/use/)): Ethereum is a blockchain based open software platform and cryptocurrency that enables developers to build and deploy a decentralized application (dApp). The network permits the execution of Turing-complete algorithms written in the programming language Solidity, on a virtual machine known as the Ethereum Virtual Machine (EVM), based on available resources from peers. A wide range of applications previously unimagined are now fueled by the network, ranging from electronic voting, compliance, trading, etc. **NEM:** NEM is an alternative blockchain-based, decentralized peer-to-peer network that enables third parties to build smart asset applications such as, but not limited to, crowdfunding tokens and cryptocurrencies. NEM uses proof-of-importance consensus rather than proof-of-stake or proof-of-work and this distinguishes it from other blockchains. NEM's benefits include multi-signature accounts, mosaics, privacy, messaging, scaling, and the fact that practically every member of the NEM community can suggest updates and developments. **NEO**[[https://nem.io/enterprise/](https://nem.io/enterprise/)]([https://nem.io/enterprise/](https://nem.io/enterprise/)): NEO's protocol offers the opportunity to execute trustless smart contracts that can be used for financial dealings, but also as a platform for more complicated transactions. It competes with Ethereum for its ease of use. It is employed mainly in Asia where it is considered a market leader. **Cardano**[[https://cardanodocs.com/](https://cardanodocs.com/)]([https://cardanodocs.com/](https://cardanodocs.com/)): Cardano is quite similar to Ethereum, allowing the deployment and execution of smart contracts. The major feature that differentiates it from Ethereum and other smart contracts is \"ouroboros\", its proof-of-stake extracting algorithm that consumes less energy than Ethereum's. Another unique feature of Cardano is its issuing of debit cards that can be funded from the user's online wallet and used as a traditional debit card.