`@penumbra-zone/keys`

This package contains cryptographic keys relevant to the Penumbra blockchain, and checksums to validate the integrity of those keys.

The default export is a JSON mapping of Penumbra Action names to their relevant key, necessary for building cryptographic proofs for those actions. Keys are exported as [key_name]_pk.bin.

A basic shell script penumbra-download-keys is provided, if you have specific versioning, bundling, or copying needs. Most users can use the keys exported from the package.

Using Keys

If your bundler supports import.meta.resolve, you can handle the raw key material like this:

const res: Result = await fetch(import.meta.resolve('@penumbra-zone/keys/convert_pk.bin'));
const keyBuf: ArrayBuffer = await res.arrayBuffer();
const convertPk = new Uint8Array(keyBuf);

A More Complex Example

If your bundler doesn't support import.meta.resolve, or you rely on customized bundling, you might want to just handle URLs. Our @penumbra-zone/wasm package expects you to input key URL strings when building Actions.

Here's a simplified example of how we use the packages together in our reference wallet extension:

import actionKeys from '@penumbra-zone/keys';

import type { FullViewingKey } from '@buf/penumbra-zone_penumbra.bufbuild_es/penumbra/core/keys/v1/keys_pb';
import type {
  Action,
  TransactionPlan,
  WitnessData,
} from '@buf/penumbra-zone_penumbra.bufbuild_es/penumbra/core/transaction/v1/transaction_pb';

// map filenames to bundled key asset URLs
const keyUrls = actionKeys.map(keyFileName => new URL(`keys/${keyFileName}`, PRAX_ORIGIN));

async function buildAction(
  txPlan: TransactionPlan,
  witness: WitnessData,
  fvk: FullViewingKey,
  actionIndex: number,
): Promise<Action> {
  // Dynamically load wasm module
  const builder = await import('@penumbra-zone/wasm/build');

  // Identify action type
  const actionType: Action['value']['case'] = transactionPlan.actions[actionPlanIndex]!.action.case;

  // Identify key url, if present
  const keyUrl: string | undefined = keyUrls[actionType]?.href;

  // Build action
  return builder.buildActionParallel(txPlan, witness, fvk, actionIndex, keyUrl);
}

Using the management script

An executable penumbra-download-keys is included. It can checksum the keys included in this package, and download other versions referenced by git tag if you are working with a testnet or other custom chain with its own proving keys.

In any workspace where this package is installed, you can use

[npm|pnpm|yarn] exec penumbra-download-keys [output-path] [git tag] [sha256 manifest]

Which will acquire the default keys and display checksum validation, if a key manifest is already present. You can further specify a version and custom manifest file.

Updating the keys

If new keys are released by core, change the defaultKeysVersion variable in the download-keys script to the new version of the keys. Then:

Run the download-keys script (per the instructions above)
cd keys
shasum -a 256 *.bin > ../shasums/vX.X.X.shasum (change vX.X.X to the actual version number of the keys)
Commit your changes.