Add getPublicKeyFromPrivateKey helper

[lorisleiva]

This PR adds a getPublicKeyFromPrivateKey helper method that can be used to retrieve the CryptoKey public key from an extractable CryptoKey private key.

import { createPrivateKeyFromBytes, getPublicKeyFromPrivateKey } from '@solana/keys';

const privateKey = await createPrivateKeyFromBytes(new Uint8Array([...]), true);

const publicKey = await getPublicKeyFromPrivateKey(privateKey);
const extractablePublicKey = await getPublicKeyFromPrivateKey(privateKey, true);

[changeset-bot]

🦋 Changeset detected

Latest commit: 0a4c8ae

The changes in this PR will be included in the next version bump.

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR

[lorisleiva]

• Add signers example #3048
• Add createKeyPairSignerFromPrivateKeyBytes helper #3051
• Add createKeyPairFromPrivateKeyBytes helper #3050
• Add getPublicKeyFromPrivateKey helper #3049 👈
• Add support for importing JWK keys in crypto polyfill #3064
• Add support for exporting keys as JWK in crypto polyfill #3063
• master

This stack of pull requests is managed by Graphite. Learn more about stacking.

Join @lorisleiva and the rest of your teammates on Graphite

[mcintyre94]

Is it possible for us to check if it's extractable? I'm wondering if we should add a Solana error for this case because I'm skeptical that subtle crypto will give a nice error message

[lorisleiva]

Good shout! I've added a new SOLANA_ERROR__SUBTLE_CRYPTO__CANNOT_EXPORT_NON_EXTRACTABLE_KEY error code.

[steveluscher]

Wow! I didn't think this was possible! Amazing.

This can't go in without this PR also including an update to the polyfill. The only reason the tests pass here is that the tests run in a haz-ed25519 environment. This will puke in a browser that doesn't.

To be clear, you need to add a polyfill that implements at least jwk export for private keys and import for public keys. Hint: the x and d coordinates are base64URL encoded.

[lorisleiva]

Thanks @steveluscher, I'll apply your suggestions and prepend PRs to the stack for the polyfill.

[steveluscher]

[lorisleiva]

Merge activity

• Aug 7, 4:34 AM EDT: @lorisleiva started a stack merge that includes this pull request via Graphite.
• Aug 7, 4:39 AM EDT: Graphite rebased this pull request as part of a merge.
• Aug 7, 4:40 AM EDT: @lorisleiva merged this pull request with Graphite.

[github-actions]

Because there has been no activity on this PR for 14 days since it was merged, it has been automatically locked. Please open a new issue if it requires a follow up.