# __fixtures__/rsa-2048-key

## Purpose

Real 2048-bit RSA keypair generated once at module-load time and exposed
as canonical `RsaPublicKey` / `RsaPrivateKey` shapes for Stage 2+ tests
(sign / verify / encrypt / decrypt). The 16-bit synthetic
`TINY_PRIVATE_KEY` fixture in `test-keys.ts` cannot host a SHA-256 EM
(32 bytes is wider than its 2-byte modulus), so signature tests need a
real-sized key.

## Features

- Real 2048-bit keypair via `node:crypto.generateKeyPairSync`
- Decoded into canonical bigint form via `finalisePrivateKey` /
  `finalisePublicKey`
- Stable within a single test run (deterministic across all tests in the
  same process); not deterministic across processes
- Re-run cost amortised across the entire Stage 2+ suite (≈ 50 ms once)

## Usage

```ts
import {
    RSA_2048_PRIVATE_KEY,
    RSA_2048_PUBLIC_KEY,
} from "../__fixtures__/rsa-2048-key.js";
```

## API Reference

### `RSA_2048_PUBLIC_KEY: RsaPublicKey`

### `RSA_2048_PRIVATE_KEY: RsaPrivateKey`

## Implementation Notes

- Tests that need byte-exact reference vectors must use one of the RFC
  8017 Appendix C / Wycheproof / CAVP fixture files (added incrementally
  ).
- The fixture is not committed bytes-on-disk; regeneration on every
  test process amortises down to noise once the rest of the suite runs.