Digital Currency Glossary: Key Terms and Definitions

The digital currency landscape spans dozens of overlapping technical, legal, and financial concepts — each carrying precise meaning within specific regulatory and operational contexts. This glossary defines the foundational terms used across the Digital Currency Authority, organized to support accurate reading of compliance documents, regulatory filings, and technical specifications. Understanding these definitions is essential for anyone navigating the regulatory context for digital currency, where agencies including the IRS, FinCEN, CFTC, and SEC apply distinct definitional standards to the same underlying instruments.

Definition and scope

A digital currency glossary serves a specific purpose: establishing shared definitional ground across technical, legal, and financial disciplines where the same term can carry materially different meanings depending on the issuing authority. The IRS, for example, defines "virtual currency" in Notice 2014-21 as a digital representation of value that functions as a medium of exchange, a unit of account, or a store of value — but does not have legal tender status in any jurisdiction. The Financial Crimes Enforcement Network (FinCEN) uses the term "convertible virtual currency" (CVC) to describe a subset that can be exchanged for real currency or other value, as codified in its 2013 Guidance FIN-2013-G001.

The scope of this glossary covers:

Terms are defined as they appear in named public documents where such definitions exist. Where no authoritative definition has been issued, the structural or functional definition in widest professional use is provided.

How it works

The following numbered entries define the core terms in the digital currency ecosystem, organized from foundational infrastructure through to market and legal classification.

  1. Blockchain — A distributed ledger in which records (blocks) are cryptographically linked in sequence, making retroactive alteration computationally prohibitive without controlling a majority of network hash power. Bitcoin's blockchain processes approximately 7 transactions per second at base layer. The NIST Interagency Report 8202 provides a taxonomy of blockchain technology components and use cases.

  2. Cryptocurrency — A digital asset that uses cryptographic techniques to control unit creation and verify transactions, typically operating on a decentralized network without a central issuing authority. Bitcoin (BTC) and Ether (ETH) are the two largest by market capitalization.

  3. Stablecoin — A digital asset designed to maintain a pegged value, most commonly to the US dollar. Mechanisms include fiat collateralization (reserves held in cash or equivalents), crypto collateralization (overcollateralized digital asset reserves), and algorithmic supply adjustment. The President's Working Group on Financial Markets addressed stablecoin risks in its November 2021 Report on Stablecoins.

  4. Central Bank Digital Currency (CBDC) — A digital form of sovereign fiat currency issued and backed directly by a central bank. Unlike cryptocurrency, a CBDC carries the full legal tender status of the issuing government. The Federal Reserve's discussion paper Money and Payments: The U.S. Dollar in the Digital Age (January 2022) outlines 9 key design considerations for a potential US CBDC.

  5. Private Key — A 256-bit cryptographic string that authorizes the transfer of digital assets from a given address. Possession of the private key constitutes de facto ownership; no recovery mechanism exists at the protocol level if it is lost.

  6. Wallet — Software or hardware that stores private keys and interfaces with a blockchain to sign transactions. Wallets do not store currency; they store credentials. Custodial wallets transfer private key control to a third party; non-custodial wallets retain it with the user.

  7. Smart Contract — Self-executing code deployed on a blockchain that automatically enforces predefined conditions without requiring an intermediary. Ethereum introduced smart contracts at scale beginning in 2015.

  8. Consensus Mechanism — The protocol by which network nodes agree on the valid state of the ledger. Proof of Work (PoW) requires computational expenditure; Proof of Stake (PoS) requires validators to lock collateral. Ethereum transitioned from PoW to PoS in September 2022.

  9. On-Chain vs. Off-Chain — On-chain transactions are recorded directly to the distributed ledger and are publicly verifiable; off-chain transactions occur outside the ledger (e.g., within exchange internal systems or payment channel networks) and are settled or batched later.

  10. Money Transmission — Under the Bank Secrecy Act (BSA) as administered by FinCEN, any person or entity that accepts and transmits currency, funds, or value that substitutes for currency may qualify as a Money Services Business (MSB), requiring registration and anti-money-laundering program compliance.

  11. Convertible Virtual Currency (CVC) — FinCEN's regulatory term for a digital asset with an equivalent value in real currency or that acts as a substitute for real currency. This classification triggers MSB registration and BSA obligations.

  12. Commodity vs. Security classification — The CFTC has asserted jurisdiction over Bitcoin as a commodity under the Commodity Exchange Act. The SEC applies the Howey Test — established in SEC v. W.J. Howey Co., 328 U.S. 293 (1946) — to determine whether a digital asset constitutes an investment contract and thus a security subject to registration requirements.

Common scenarios

Scenario A: Tax reporting classification
When an individual sells cryptocurrency for a profit, the IRS treats the transaction as the sale of property, not currency. Under IRS Revenue Ruling 2023-14, taxpayers who receive crypto as income (including staking rewards) must recognize gross income at the fair market value on the date of receipt. The applicable form is Schedule D, with digital asset transactions now reported on Form 1040 beginning with the 2019 tax year.

Scenario B: Exchange registration requirements
A platform that matches buyers and sellers of digital assets and holds customer funds qualifies as a Money Services Business under FinCEN's framework. Such platforms must register with FinCEN, maintain a written anti-money-laundering (AML) program, file Suspicious Activity Reports (SARs), and comply with the Bank Secrecy Act's recordkeeping requirements under 31 CFR Part 1022.

Scenario C: CBDC vs. stablecoin differentiation
A CBDC issued by the Federal Reserve would carry legal tender status, be denominated in US dollars at 1:1 parity by statute, and carry no counterparty default risk at the issuer level. A USD-pegged stablecoin issued by a private entity carries counterparty risk tied to reserve quality, is not legal tender, and is subject to the issuer's redemption policies. The President's Working Group report (cited above) identified reserve asset quality and redemption risk as the 2 primary stability vulnerabilities in private stablecoins.

Decision boundaries

When is a digital asset a security?
The SEC's application of the Howey Test requires 4 elements: (1) an investment of money, (2) in a common enterprise, (3) with an expectation of profits, (4) derived from the efforts of others. Digital assets sold through initial coin offerings (ICOs) frequently satisfy all 4 prongs. Assets with fully functional, decentralized networks — where no central promoter's efforts drive value — are more likely to be classified as commodities by the CFTC.

Custodial vs. non-custodial regulatory treatment
Custodial wallet providers that hold private keys on behalf of users are generally treated as money transmitters under FinCEN guidance. Non-custodial wallet software providers, where the user retains sole key control, have not historically been classified as MSBs under the same framework, though regulatory developments in this area remain active.

Fiat vs. crypto collateralized stablecoins
Fiat-collateralized stablecoins (e.g., reserves held in US Treasury instruments or cash equivalents) carry lower price volatility but introduce centralization and counterparty risk. Crypto-collateralized stablecoins require overcollateralization ratios — often 150% or greater — to absorb underlying asset volatility and maintain peg integrity.

On-chain settlement finality vs. traditional payment finality
Traditional ACH transactions carry a 2-business-day standard settlement window and are reversible during that period under Nacha operating rules. Bitcoin transactions are considered probabilistically final after 6 confirmations (approximately 60 minutes), with no native chargeback mechanism at the protocol level.

References

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