arxid

A Keyed, Reversible Permutation for ID Obfuscation
The arxid project provides a method for obfuscating sequential integer identifiers by transforming them into a fixed-length, non-enumerable 7-character code. This transformation ensures that the obfuscated codes are identical across multiple programming languages, thus maintaining consistency and interoperability.

Key Features

• Reversible Transformation: Convert sequential IDs into 7-character codes that can be easily reversed back to the original IDs using a specified key.
• Consistent Across Languages: The implementation guarantees that the same input will yield the same output in any language that adheres to the spec, ensuring compatibility across systems.

Example Usage

Here's how arxid functions in Rust:

let arxid = Arxid::new(key);

let obfuscated_code = arxid.obfuscate_str(1001);   // Produces: "Cc1W2dQ"
let original_id = arxid.deobfuscate_str("Cc1W2dQ");   // Returns: Some(1001)

The Problem Addressed

Sequential IDs expose information about the ordering and volume of records, which can lead to data exposure risks. By using arxid, applications can keep their internal sequential IDs private while still presenting a user-friendly code format to external users, effectively hiding underlying data growth patterns.

Technical Overview

The core of arxid is a balanced Feistel network utilizing an ARX (Add-Rotate-XOR) round function over a 40-bit domain. The process includes:

• 4 rounds of permutation.
• A fixed output format of 7 base62 characters, covering a massive range of identifiers (up to about 1.1 trillion values).

Performance

Performance benchmarks indicate that arxid is optimized for speed with:

• Obfuscation of raw integers achieving ~225 million operations per second.
• Deobfuscation performing at ~101 million operations per second.

Portability and Canonical Vectors

The project is designed as a frozen specification with associated canonical test vectors. This means any implementation that complies with the spec can be validated against a defined set of known outputs, leading to consistent behavior across multiple programming environments.

Security Considerations

While arxid provides an effective means of obfuscating IDs, it is important to note that it is not a security solution. It provides no encryption or authentication; thus, it should not be solely relied upon for securing sensitive data. Always combine with adequate security measures to protect crucial information.

When to Use

Choose arxid when the requirement is:

• For preserving the length of obfuscated outputs to precisely 7 characters.
• To implement a system where consistent ID obfuscation across languages is critical, while maintaining the ability to revert to original values with a key.

For additional insights, specifications, and implementation details, refer to the full documentation linked in the repository.