noscrypt

A compact, C90 cross-platform, cryptography library built specifically for nostr

What is noscrypt?

A high-level C utility library built specifically for nostr cryptography operations such as those defined in NIP-01 and the new NIP-44 (NIP-04 coming soon). Noscrypt simplifies key generation, note signing & verification, NIP-44 data encryption, NIP-44 private message encryption, and much more. Noscrypt has very low dependency requirements with a focus on portability and performance for desktop and (eventually) embedded systems alike.

API Example:

NCValidateSecretKey()
NCGetPublicKey()
NCSignData()
NCVerifyData()
NCEncrypt()
NCDecrypt()
NCComputeMac()
NCVerifyMac()
... extended functions

Motivation

At the time of building this project I have not come across any C-only libraries that exposed functionality for nostr specific cryptography. IMO it is easy to use the secp256k1 library incorrectly. In the process of building NVault NIP-44 came out in December and I realized my libraries were falling short for my needs for proper and safe nostr cryptographic operations, and I needed to start over and start with a good base that has all the basic functionality built with trusted and tested libraries. I also really care about performance and resource requirements that many other nostr projects seem to completely ignore, if you follow me on nostr, you know I can be quite the pest.

Testing

Testing is an will be important to a cryptography library, I take that responsibility seriously. My goal is to achieve enterprise level testing and security. There are some basic api validation and correctness tests that can be built into an executable called nctest. Full automated testing suite is done in C# interop. This includes testing against the official NIP-44 vector file. I'm very dependency adverse so native C90 testing using only stdlibs can get gross in a hurry. It will likely happen in the future but not right now.

Hardness

Time sensitive verification always uses fixed time comparison
No explicit/dynamic memory allocations (in core library)
Valgrind is used to check for runtime memory leaks and overflows
CI Requires %100 test pass before merging
Public API function input validation is on by default
All stack allocated structures are securely zeroed before return
Stack protection is enabled by default for GCC and MSVC compilers
Schnorr signatures are validated before the signing function returns
Carefully selected, widley used, tested, and audited dependencies

Platform Support

The following table lists the supported platforms and cryptography libraries that noscrypt supports. This will expand in the future. You are free to choose and specify the location of these libraries if you desire during build time, otherwise safe defaults are attempted on your platform.

Arch	Support	Notes	Tested
Windows	OpenSSL (3.0+), Mbed-TLS, BCrypt	NT 6.1 +	✅
Linux	OpenSSL (3.0+), Mbed-TLS	GCC only	✅
FreeBSD	OpenSSL (3.0+), Mbed-TLS	GCC Only

Security Policy

Please see the SECURITY.md file for more information on how to report security issues.

Getting started

GitHub and Codeberg are only mirrors for my projects. Extended documentation, pre-compiled binaries and source code bundles are always available on my website, along with PGP signatures and checksums.

Project homepage
Startup & Install Guide
Extended Documentation

Super quick start

If you are in a hurry to try out noscrypt these steps will get you by. Otherwise website documentation is authoritative and I encourage you read the docs.

Prerequisites

Supported operating system and compiler from table above
CMake build system
Taskfile.dev to execute build recipe

mkdir noscrypt/ && cd noscrypt/
wget https://www.vaughnnugent.com/public/resources/software/builds/noscrypt/<master-git-hash>/noscrypt/noscrypt-src.tgz
tar -xzf noscrypt-src.tgz
task
sudo task install

Notes

Builds

Build packages on my website are now fully automated and signed with my PGP key.

Branches

I use 2 main branches for development. master is considered as stable as a release tag, develop is a staging branch for all changes before they are merged into master. When submitting PRs please target and use the latest develop branch. Feature branches are created as necessary and merged into develop when ready for staging.

I am also a member of GitCitadel so feel free to send some sats that way too!