Aerospace and defense is not an obvious home for blockchain. The sector runs on classified networks, legacy procurement systems, and multi-decade platform lifecycles. Yet the same properties that make distributed ledger technology attractive to finance and logistics—immutable records, decentralized verification, cryptographic auditability—map with unusual precision onto the hardest operational problems in A&D: parts provenance, contractor accountability, and multi-jurisdiction data sharing.

The market reflects growing institutional recognition of this fit. Defense procurement agencies and prime contractors have moved from exploratory pilots to funded programs, with blockchain embedded in supply chain management, maintenance records, and secure communications infrastructure.

Decentralized lending protocols allow users to borrow and lend cryptocurrency through smart contracts, without any underwriting institution, credit bureau, or loan officer involved in the process. The model replaces credit assessment entirely with collateralization — a user who wants to borrow must first deposit more than the borrowed amount in a different cryptocurrency, and the smart contract manages the rest.

The process begins with a liquidity provider depositing an asset — say, ether — into a lending protocol. That deposit is available for borrowers to withdraw, provided they first lock collateral into the same smart contract. Lending in defi generally requires over-collateralization: the collateral deposited must exceed the value of the loan, often significantly, to provide a buffer against the price volatility common in cryptocurrency markets. The smart contract tracks the loan-to-value ratio continuously, relying on oracles to feed it current price data for both the collateral and the borrowed asset.

A decentralized exchange, or DEX, is a trading platform that holds no assets in custody, employs no order book in the traditional sense, and requires no registration from its users. It executes trades directly from pooled liquidity through a smart contract, and the mechanism by which it prices assets is encoded in mathematics rather than determined by a counterparty.

The central innovation enabling DEXes is the automated market maker, or AMM. In a traditional exchange — including a centralized crypto exchange — buyers and sellers are matched based on the quantities and prices at which they are willing to transact, recorded in a central order book. An AMM eliminates the order book entirely. Instead, it manages a liquidity pool: a smart contract holding two assets in a trading pair, into which liquidity providers deposit equal values of both assets. Users trade directly against the pool, depositing one asset and withdrawing the other, with the price determined by the ratio of the two assets in the pool at the time of the trade.

A smart contract is a piece of software that executes automatically when predetermined conditions are met. It requires no human to process it, no institution to authorize it, and no counterparty to trust it. In the context of decentralized finance, this is not a minor technical detail — it is the entire architecture. Defi exists because smart contracts make it possible to replicate the functions of financial intermediaries in code.

Decentralized finance — defi — is not a single product or platform. It is a collection of financial goods and services that operate through automated software programs called smart contracts, running on public blockchains, accessible in principle to anyone with the requisite technical knowledge and some quantity of cryptocurrency. The Congressional Research Service, in an April 2026 overview of the sector, defines it as a system characterized by “highly automated financial networks that have no single point of failure, do not rely on a single source of information, and are not governed by a central authority.”