runtime-sdk/src/modules/core: add "core.KeyManagerPublicKey" call

[CedarMist]

Re: oasisprotocol/sapphire-paratime#366

Adds core.KeyManagerPublicKey which returns the runtime signing public key.

This key signs the ephemeral keys, one of which is the per-epoch call data public key, used for encrypting transaction data.

I have modified core.CallDataPublicKey to return both the Runtime ID and the Key Pair ID, both of these are necessary information to validate the signature. The remaining information (such as the checksum, expiration & epoch) are already returned by core.CallDataPublicKey

TODO

• Validate calldatapublickey in JS client.
• Return key_pair_id and runtime_id from core.CallDataPublicKey
• Return only 32 byte runtime signing public key from core.KeyManagerPublicKey
• Add tests to ensure coverage

Result is the 32 byte runtime signing public key.

[netlify]

✅ Deploy Preview for oasisprotocol-oasis-sdk canceled.

Name	Link
🔨 Latest commit	50658ab
🔍 Latest deploy log	https://app.netlify.com/sites/oasisprotocol-oasis-sdk/deploys/671b4fcf12e0100008bb3c09

[codecov]

Codecov Report

Attention: Patch coverage is 10.52632% with 17 lines in your changes missing coverage. Please review.

Project coverage is 59.10%. Comparing base (f735ef9) to head (3d06649).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
runtime-sdk/src/modules/core/mod.rs	10.52%	17 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1996      +/-   ##
==========================================
- Coverage   59.20%   59.10%   -0.10%     
==========================================
  Files         129      129              
  Lines        9592     9611      +19     
==========================================
+ Hits         5679     5681       +2     
- Misses       3913     3930      +17     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[CedarMist]

So, ran into some problems.

So secrets::get_public_ephemeral_key uses kdf.sign_pubic_key, which signs the key using kdf.inner.signer
But... I can't get the inner.signer public key through the keymanager API, and it's not the long term key pair (which I assumed had been signing the ephemeral keypairs) that I need - it's the signer
signer is derived from derive_signing_key with the master secret & runtime ID, and the ekiden-derive-signing-key namespace, whereas long-term keys are derived using ekiden-derive-runtime-secret namespace via get_or_create_longterm_keys

[CedarMist]

Relies on oasisprotocol/oasis-core#5865 being merged into oasis-core, so we can use it in new oasis-sdk.

[kostko]

This is now available in the main branch that uses Oasis Core 24.3.

The key manager trait now provides runtime_id and runtime_signing_key.