reverse engineering
Reverse engineering is the process of studying a product, device, software program, or other finished product to understand how it was designed, created, or operates. Reverse engineering can include taking apart a physical object, testing a product, analyzing code, algorithms, or the general behavior of a system. In legal disputes, the significance of reverse engineering usually depends on the context of how the item or information was obtained, what the person does with what is learned, and which area of law applies.
In trade secret law, reverse engineering can be a lawful way to obtain information. The Defend Trade Secrets Act (DTSA) defines improper means to include theft, bribery, misrepresentation, breach or inducement of a breach of a duty to maintain secrecy, and espionage, but states that improper means do not include reverse engineering, independent derivation, or other lawful means of acquisition. As a result, the owner of a trade secret may not be able to use trade secret law to stop someone from learning information by lawfully obtaining a product and reverse engineering it. However, if the person obtained access through theft, fraud, a breach of a non-disclosure agreement, or other improper means, then reverse engineering may still create liability. Reverse engineering can also intersect with contract, patent, and copyright law. Parties may agree by contract not to reverse engineer a product or software, and violating that promise may lead to a breach of contract claim if the restriction is enforceable under the governing law of that jurisdiction. If a product or method is protected by a patent, reverse engineering might not by itself give permission to make, use, sell, offer to sell, or import the patented invention in a way that constitutes patent infringement.
Copyright law may apply when reverse engineering software requires copying code. At times, courts have treated intermediate copying during software reverse engineering as fair use when the copying was necessary to access unprotected functional elements needed for compatibility. For example, in Sega Enterprises Ltd. v. Accolade, Inc., 977 F.2d 1510 (1992), the Ninth Circuit held that disassembling copyrighted object code to learn functional requirements for compatibility could qualify as fair use under the circumstances of that case.
The Digital Millennium Copyright Act (DMCA) adds separate anti-circumvention rules. Section 1201(f) permits certain circumvention by a person who has lawfully obtained the right to use a copy of a computer program, solely to identify and analyze elements necessary to achieve interoperability of an independently created computer program with other programs, to the extent the acts do not constitute copyright infringement or violate other applicable law.
Reverse engineering is not categorically legal or illegal. Nonetheless, reverse engineering may create liability when it involves improper access, unlawful circumvention, infringement, breach of contract, or use of another person’s trade secret acquired through improper means.
[Last reviewed in July of 2026 by the Wex Definitions Team]
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