After running Lockpick_RCM, navigate to the /switch/ folder on your SD card. You should find:

In the world of Nintendo Switch custom firmware (CFW) and homebrew development, file management and key handling are critical. Among the many tools that have emerged to streamline these processes, NSC Builder stands out as a powerful, all-in-one software suite used to manage, convert, and patch Nintendo Switch game files (NSP, XCI, NSZ, etc.). At the heart of its operation—and a frequent source of confusion for new users—lies a humble but vital text file: nsc builder keys.txt.

If you have ever downloaded NSC Builder, unzipped it, and stared at a blank keys.txt file wondering what to do next, this article is for you. We will explore what this file is, why it is indispensable, how to source and format it correctly, and best practices for troubleshooting common key-related errors.

As of 2025, NSC Builder remains in semi-active development (last major build 1.01). The tool’s dependency on keys.txt is not likely to change, but future Switch firmware updates may introduce new key generations (e.g., AES-MAC changes). Always use the latest Lockpick_RCM payload to re-extract keys after a system update.

Some community forks are exploring keyfile-less operation for basic functions, but full decryption will always require cryptographic keys.