Introduction

The Truepic C2PA library, called libc2pa, is a proprietary library built for enterprises, written in C++ to perform C2PA signing and validation operations on media files.

Target Environments

Truepic's CI workflows currently build and test libc2pa the following platforms:

• MacOS 13 (x86_64 and aarch64)
• Ubuntu 20.04 (x86_64)
• Amazon Linux 2 (x86_64)
• Web Assembly (for browsers and Node.js)
• Android
• iOS

We have also built for other platforms, including Arch Linux and Windows. Other platforms may be added upon request.

Bindings

Bindings are available for C, C#, Java, JavaScript, and Rust integrations. Those bindings are not currently documented here, but more information can be provided upon request.

Current State

The library is in active development. New features are being added regularly. Some features in the library are in an experimental state, or even incomplete. Some features may be removed in future versions. Up until now, the library has been developed with a "functionality-first" mentality. Performance has been a secondary consideration. As such, there are likely many unexplored opportunities to improve the library's performance.

The library is on the 5th iteration of its interface (v5). The v4 interface is still supported, but is deprecated. Interfaces older than v4 are no longer supported in the library. See Signing v4 and Validation v4 for documentation on the v4 interface.

Example Code

There are a couple of example binaries that provide a pretty good model for how to use the libc2pa interface:

• examples/example.cpp - Shows how to use a buffer "flavor" of the ClaimGenerator to sign a JPEG image.
• examples/example_mp4.cpp - Shows how to use a file "flavor" of the ClaimGenerator to sign an MP4 video.