WiseOwl.Demeanor.MSBuild 6.1.1

WiseOwl.Demeanor.MSBuild

Build-time obfuscation for .NET projects. From the original .NET obfuscator, shipping since 1999.

Add a <PackageReference>, set one MSBuild property, and dotnet build runs obfuscation as part of every Release build. No global tool install required, no separate CI step, no per-machine setup. dotnet restore pulls the package; the bundled obfuscator runs as a build target.

Learn more at www.wiseowlsoftware.com

Install

dotnet add package WiseOwl.Demeanor.MSBuild

That's it. Release builds auto-obfuscate; Debug builds and test projects are auto-skipped. No csproj edit required.

dotnet build -c Release
# → bin/Release/<tfm>/MyApp.dll is obfuscated, in place

The package's built-in default is equivalent to:

<PropertyGroup Condition="'$(Configuration)' == 'Release'">
  <Obfuscate>true</Obfuscate>
</PropertyGroup>

Change true to false if you want to disable obfuscation for some reason.

Test projects (anything where Microsoft.NET.Test.Sdk has set IsTestProject=true — xunit / mstest / nunit) auto-skip even on Release; obfuscating a test assembly would break the runner's reflection-based discovery.

What it looks like

// Your code
public class PriceCalculator
{
    private readonly decimal _discount = 0.10m;

    public decimal Apply(decimal price)
    {
        Console.WriteLine($"Discount: {_discount:P}");
        return price - (price * _discount);
    }
}

After Enterprise obfuscation, decompiled with ILSpy:

public class a
{
    private decimal m_a;

    public decimal  (decimal a)
    {
        b.c(b.a("\u0003\rÍÆ0\u001C"), this.m_a);
        return a - (a * this.m_a);
    }
}

Method name is literal whitespace — invalid C# at the parser. Strings encrypted into a decryptor call. Try to recompile:

$ dotnet build
CS1001: Identifier expected
Build FAILED.

Plus integer constants encrypted, control flow obfuscated, anti-tamper and anti-debug injected. The decompiler shows you something — but it's unreadable, won't compile, and the literal "Discount: {_discount:P}" is gone. (Real ILSpy output.)

Common properties

Every Demeanor CLI option is exposed as a <Demeanor*> MSBuild property — disable individual passes (<DemeanorStringEncryption>, <DemeanorCfg>, <DemeanorAntiTamper>, etc.), tune thresholds (<DemeanorProxyThreshold>16</DemeanorProxyThreshold>), or pass through strong-name keys (<DemeanorKeyFile>...</DemeanorKeyFile>). The targets file at build/WiseOwl.Demeanor.MSBuild.targets documents the full property surface.

Exclusions as MSBuild items

<ItemGroup>
  <DemeanorExclude Include="MyApp.Models.ApiResponse" />
  <DemeanorExcludeRegex Include=".*ViewModel$" />
  <DemeanorExcludeAssembly Include="ThirdParty.Library" />
</ItemGroup>

Per-project obfuscation policy lives in the .csproj next to the rest of your build configuration — versioned, code-reviewed, and CI-friendly.

License key

Set the DEMEANOR_LICENSE environment variable (CI secret, shell profile, etc.). There is no <DemeanorLicense> MSBuild property by design — license keys do not belong in source-controlled .csproj files.

Without an Enterprise key, Demeanor degrades to Community-tier basic renaming. All advanced protection — encryption, control-flow obfuscation, call hiding, anti-tamper, anti-debug, aggressive renaming, and the AI-assisted workflow — is Enterprise-only.

Licensing

Per-company licensing — no seat counting, no machine locking. RSA-signed keys validated entirely offline.

Pricing and purchase: www.wiseowlsoftware.com/pricing.

Companion: WiseOwl.Demeanor global tool

For ad-hoc CLI use (demeanor audit, demeanor check, demeanor deobfuscate, inspector, and the Claude Code /obfuscate workflow with built-in MCP server), install the global tool:

dotnet tool install -g WiseOwl.Demeanor

This MSBuild package and the global tool share the same self-contained obfuscator binary internally — install whichever (or both) matches your workflow.

Documentation

Full documentation including MSBuild property reference, exclusion patterns, CI/CD integration (GitHub Actions, Azure DevOps, GitLab CI), framework-by-framework guidance, and troubleshooting:

www.wiseowlsoftware.com/docs

About Wise Owl Software

Demeanor is published by Wise Owl Software, founded by Brent Rector in 1990. Brent has been writing software for over five decades and spent two decades at Microsoft as a Principal Software Architect — a decade directly on the Windows operating system itself, plus years on Visual Studio, the Windows SDK, and .NET. Demeanor's first beta shipped in June 2000 alongside .NET Beta 1, and the same author has continuously developed and maintained it across every release since.

www.wiseowlsoftware.com

Copyright (c) Wise Owl Software. 1999-2026. All Rights Reserved. Commercial product; see LICENSE for the EULA.