kent-id/obfuscation

Obfuscation / Integer Masking library to encrypt numeric id to short string, generating a similar result to YouTube video id.

Cryptography.Obfuscation

Obfuscator is a C# library that converts a non-negative integer into 8-character string, generating a result similar to YouTube video id. Put it simply, this library converts a numeric id such as 127 to xVrAndNb and back.

Preface

Obfuscation is not designed to to replace your authentication layer, but simply to provide an additional security step. Ideally, your application should be able to authenticate request without, for example, masking/obfuscating id in the query string.

Install

Install-Package Kent.Cryptography.Obfuscation

nuget package link: https://www.nuget.org/packages/Kent.Cryptography.Obfuscation/

Obfuscator 2.0

Obfuscator 2.0 uses a slightly different algorithm compared to version 1.0. New algorithm is introduced to achieve true constant mode across all .NET versions. Prior to version 2.0, constant mode will still achieve expected result as long as you don't change the target framework of your project. If you have been using version 1.0.1 and finds this limitation acceptable, it's safe not to upgrade.

Usage

Basic Example

Provides unique id <> string mapping which will not change unless Seed value is changed.

  var obfuscator = new Obfuscator();
  string obfuscatedID = obfuscator.Obfuscate(15);   // e.g. xVrAndNb
  
  // Reverse-process:
  int deobfuscatedID = obfusactor.Deobfuscate(obfuscatedID);  // 15

Randomized Mode

Generates randomized sequence which will cause the Obfuscate function to generate different values even when obfuscating the same id.

  var obfuscator = new Obfuscator();
  obfuscator.Strategy = ObfuscationStrategy.Randomized;
  
  // 'randomized' to generate different sequence for the same id.
  string obfuscatedID = obfuscator.Obfuscate(15);         // e.g. MzQgC4rL
  string secondObfuscatedID = obfuscator.Obfuscate(15);   // e.g. 4sucAs0D
  
  // Reverse-process:
  int deobfuscatedID = obfusactor.Deobfuscate(obfuscatedID);    // 15
  deobfuscatedID = obfusactor.Deobfuscate(secondObfuscatedID);  // 15

Seed Value

Seed value is the 'differentiator' that makes id <> string mapping unique to your application. It is highly recommended to set this value rather than depending on the default value set by the library (which is 113).

  var obfuscator = new Obfuscator();
  obfuscator.Seed = 167;
  string obfuscatedID = obfuscator.Obfuscate(15);

Note: Minimum seed value is 2 and it's recommended to set this value to varying digits (instead of something like 100), as this will be used in XOR operations. Some example of recommended seed values are 113, 167, 73, etc.

License

This project is licensed under the GNU Public License v3.0. Feel free to reuse for personal and commercial use.