SourceAFIS is one algorithm with two nearly identical opensource implementations for Java and .NET. Source code and binaries for both Java and .NET are linked below.
SourceAFIS for Java
Get SourceAFIS for Java from Maven Central.
<dependency> <groupId>com.machinezoo.sourceafis</groupId> <artifactId>sourceafis</artifactId> <version>2.2.0</version> </dependency>
SourceAFIS for .NET
Latest stable release of SourceAFIS for .NET is at version 1.7. You can download it as a ZIP file:
There is an experimental version 2.0 that mimicks APIs of the Java version, but it is untested and likely broken. You can try to hack its source code though:
There is an unofficial 3rd party NuGet package that is no longer maintained. I recommend using the ZIP file linked above to ensure you have an unmodified copy of SourceAFIS.
SourceAFIS is distributed under Apache License 2.0.
If you would like to test SourceAFIS, but you don't have any fingerprint reader nor fingerprint images at hand, you can download sample fingerprints from several sources: