Read the code.
The security of a secret-sharing app is the math inside it. So the math is public, and you can check it line by line.
The repository
The cryptographic core lives at github.com/norsehorse-dev/QuorumPonyCore under the Apache License 2.0. Clone it, build it, audit it, or fork it.
What's inside
- Shamir Secret Sharing over GF(2^8). Splitting builds a random polynomial whose constant term is the secret and evaluates it at distinct points; recovery is Lagrange interpolation from any K of those points.
- Constant-time field arithmetic. Multiplication and inversion in GF(2^8) run in constant time, so the implementation does not leak the secret through timing.
- No external dependencies. The core is self-contained, which keeps the audit surface small and means there is nothing pulled in that you cannot read.
Why open the core
A backup scheme is only worth trusting if the claim "fewer than K cards reveal nothing" is actually true in the code, not just on the box. Publishing the core means that claim is checkable. You can confirm the field math, confirm that a single share carries no information about the secret, and confirm there is no hidden network call or stored copy.
License
Apache-2.0. Use it, modify it, ship it, with attribution and the standard patent grant. The full text is in the repository's LICENSE file.
The sibling cores
QuorumPony's cousins publish their cores too. AgePony ships AgePonyCore, PGPony publishes PGPonyCore (Swift) and PGPonyCore-Kotlin, and RelayPony is public too, all Apache-2.0. Same developer, same habit of putting the crypto in the open.