Through their research Nexus found that most projects built on Ethereum do not use the Ethereum Virtual Machine (EVM) for its turing completeness, i.e. its ability to do universal computation. What businesses require from blockchain technology are contracts that function more like real-world actions between people, with the addition of an immutable data layer capable of managing rights and ownership. Therefore, Nexus developed an easily accessible and versatile Software Stack where data can be operated on, its ownership transferred between users, and whereby conditions define the behavior of actions. The design not only provides numerous ready-made contract functionalities, but it is also able to scale with the growing demand for smart contracts.
The Nexus architecture is designed as a seven-layered software stack that includes a 64-bit register-based contract engine. Each layer is designated to carry out a specialized process independently of one another, providing additional functionality to the existing Internet stack, the OSI model.
Register-Based Virtual Machine
A register is the fastest storage medium inside your computer’s CPU (Central Processing Unit), that the processor uses to cache data in-between calculations. The Nexus Contract engine follows this architecture as an improvement to other blockchain-powered virtual machines such as the EVM (Ethereum Virtual Machine) that still use the older stack architecture. The improved efficiency gained through the use of registers makes developing on Nexus not only easier but also much more efficient and scalable.
A basic Nexus contract is comprised of three layers: data (Registers), programmable actions (Operations), and accounts (Signature Chains). Together, these layers verify the information of a system or DApp, following a logic that closely relates to agreements and contracts between people.
Nexus has followed this approach for the primary reason that smart contracts cannot be realized with existing language designs, they require a new architecture. This is in direct contrast to EOS’s use of Web Assembly (WASM), which was designed for web development rather than building secure financial applications.
Conditional Contracts allow a user to set requirements in order for a contract to be fulfilled, such as contract time expiration, the decentralized exchange of an asset, or a non-custodial escrow services.
The Lower Level Library (LLL) is a high-performance ‘Template Library’ designed to power emerging-web technologies. The LLL is simple, powerful, and lightweight. It contains three main components: Cryptography (LLC), Database (LLD), and Protocol (LLP).
The Lower Level Database (LLD) is Nexus’ modular storage engine, which according to tests done by Nexus, is capable of outperforming most existing embedded database engines, achieving 100,000 writes and reads to disk in 0.33 seconds – rivaling Google’s LevelDB.
The Lower Level Protocol (LLP) is a core component of the Network Layer, a light and fast protocol that allows developers to customize their packet design and message interpretation. It gains scalability through simplicity and is capable of managing a large number of simultaneous connections.
The Lower Level Cryptography (LLC) is a light library that contains many useful cryptographic functions such as Post-Quantum Cryptography, AES, and Argon2.
Another aspect that makes Nexus different from other blockchains is the resistance to quantum computers. Signature Chains enhance the security of existing DSA (Digital Signature Algorithm), by hashing the public key until it is used while changing the key pair with every transaction. Nexus has also integrated the following cryptographic functions: FALCON (a second-round contender for the NIST Post-Quantum cryptography competition), Argon2 (winner of the password hashing competition, and a superior alternative to S-Crypt or B-Crypt), and Keccak (winner of the SHA3 competition). Nexus, in theory, belongs to one of the few cryptocurrencies that are resistant to a hypothetical quantum attack.
Nexus has implemented the LISP (Locator Identity Separation Protocol) network architecture, which allows the Nexus blockchain to run over a secure open overlay. LISP was created by Dino Farinacci, in partnership with several Cisco engineers, and is being developed and standardized by the Internet Engineering Task Force (IETF).
With LISP, the user receives an EID (end-point ID), which is a static identity. The EID becomes the “trust key” for a user’s identity. This EID is like an address that remains assigned to a user and is independent of how and where they connect to the network.
As LISP provides a direct route for information to travel, there is no risk of intercepting data packets in the middle of information transfer, giving privacy for transactions as well. The integration of LISP also gives Nexus a scaling advantage by selecting the shortest paths between locations of nodes, allowing them to be located anywhere on the Internet.