Git repo tokens for the security service

This post explains the internal algorithm used by VSTS to generate security tokens for Git resources, particularly branches. It details how case-sensitive Git ref names (e.g., 'master') are encoded into a case-insensitive string format (e.g., 'refs/heads/6d0061007300740065007200') to be used with the VSTS security REST endpoint and TFSSecurity.exe. The explanation covers the token structure (repoV2, project ID, repo ID, resource path) and the UTF-16 little-endian encoding of characters for case-insensitive transport. Code snippets in C# and Python are provided to illustrate the encoding algorithm.