SeriousBit Ellipter is a .NET library that utilizes Elliptic Curves Asymmetric Cryptography to license shareware apps and components. Its 3-line code can verify and create secure product keys, supported by Linux/Mono 2.0.

With Ellipter, creating or verifying secure product keys can be done in just 3 lines of code. You can easily protect your .NET and Linux/Mono based applications and components, programatically creating and verifying secure product keys. The integrated UI makes it easy to verify any key and create thousands of keys in just two clicks.
Ellipter's encryption is robust, using an asymmetric elliptic curves encryption algorithm. This makes it impossible for a cracker to create any keygens through reverse-engineering your code, or even having full access to it. Plus, its product keys are compact and as short as possible, 29 characters when no product info is embedded.
Each generated license key contains an ID, guaranteeing license key uniqueness and allowing identification of license keys. Additional product information can also be embedded into license keys when they are generated, which can be used for specific software features.
Ellipter's User Interface is full-featured, offering Public/Private keys pair Generator, Serials Generator, and Serials Validator. It is also licensed per developer, allowing for the building of as many applications as desired and distributed without paying further royalties.
With its simplicity of use, writing just 3 lines of code is all that is needed to take advantage of its capabilities. Ellipter supports NET 1.1/2.0/3.0/3.5 and Linux/Mono 2.0, allowing the use of the existing infrastructure without changes to create online key generators or protect Windows and Linux applications. C# and Visual Basic examples are also included, making it easy to get started.
Version 1.8.6: - Added BackTimeTolerance property to TimeBomb and UsageBomb classes;