How to prove software copyright infringement: a step-by-step legal & technical breakdown

Software is one of the most valuable forms of intellectual property a business can own. Its originality, functionality, and performance often represent years of development and millions in investment. So, when a competitor or third party uses your code without permission, the damage is not only financial—it’s foundational.

But proving that your software was copied or misused isn’t as simple as showing two applications look or behave similarly. Software copyright infringement claims in legal proceedings require a detailed combination of legal argument and technical evidence.

At Eureka Software, we’ve supported dozens of copyright cases with deep forensic analysis, code comparisons, and clear, courtroom-ready expert testimony. In this blog, we’ll walk through what’s required to prove (or defend against) a software copyright infringement claim—from the legal framework to the technical tools used in expert analysis.

What Is Software Copyright Infringement?

Copyright protects the original expression of an idea, not the idea itself. In software, this means:

A copyright holder must prove:

Step-by-Step Breakdown: How to Prove Infringement

1. Establish Copyright Ownership

To begin, the plaintiff must show they own the copyrighted software. This may include:

This step is foundational. Without a valid ownership claim, no infringement case can move forward.

2. Access: Was the Software Available to the Alleged Infringer?

Next, the plaintiff must show that the defendant had access to the copyrighted code. Common scenarios include:

Even indirect access can be enough if there’s a reasonable opportunity to view or use the protected work.

3. Prove Substantial Similarity

This is the most technical—and often most contested—part of the case. Courts require proof that the two programs are substantially similar in ways that suggest copying, not coincidence or shared industry practices.

At Eureka Software, our experts use a three-tiered approach:

A. Literal Code Comparison

We examine whether specific lines, functions, or files were copied, using forensic tools to:

Even small blocks of code, if copied verbatim, can be enough to support infringement claims.

B. Non-Literal Similarities

We also analyze:

Even if the literal code differs, copying may be shown if the structure and function are derived from the original.

C. Filtering Out Unprotectable Elements

Not all code is protectable. Our analysis filters out:

This ensures the court focuses on original, protectable expression rather than generic coding practices.

4. Use Forensic Evidence to Strengthen the Case

Forensic evidence can be key to proving access and copying in modern litigation. Our team often examines:

We help show how and when code was copied—or establish that similarities stem from independent development.

5. Expert Witness Testimony: Making the Technical Clear

Even the most compelling technical evidence must be explained clearly to the court. Judges and juries often lack a software background, so they need help understanding what makes two programs similar, different, or potentially infringing.

Eureka Software provides:

Our role is to identify infringement and ensure the court understands the significance of our findings.

Defending Against Infringement Claims

On the other side of the courtroom, defendants can challenge infringement claims by showing:

In one case, a client was accused of copying an entire software module from a former partner. Our forensic investigation revealed that the overlapping functions were based on open-source standards and implemented differently. The court dismissed the case, saving our client from costly litigation.

Evidence Matters — Let Eureka Software Help

Proving software copyright infringement requires more than suspicion or surface-level similarities. It demands detailed technical analysis, a deep understanding of copyright law, and the ability to communicate complex findings to a legal audience.

At Eureka Software, we specialize in this intersection. Our work supports both plaintiffs and defendants navigate the challenges of software copyright cases, providing the clarity, expertise, and courtroom experience needed to get to the truth.

Contact us today to learn how we can support your copyright litigation with expert source code analysis, forensic review, and clear, defensible testimony.