Add RECOVER_KEY_SAFE protocol feature

[conr2d]

Change Description

Implement EEP-9.

Change Type

Select ONE:

• [ ] Documentation

• [ ] Stability bug fix

• [x] Other

• [ ] Other - special case

Testing Changes

Select ANY that apply:

• [ ] New Tests

• [x] Existing Tests

• [ ] Test Framework

• [ ] CI System

• [ ] Other

Consensus Changes

• [x] Consensus Changes

API Changes

• [ ] API Changes

Documentation Additions

• [ ] Documentation Additions

[conr2d]

Can you assign anyone who may review this? It would be good if I can get a review before writing test cases.

• API design
• Additional feature for recovering uncompressed key (#6718)

According to Bitcoin secp256k1 convention, recovery IDs in the range of 27 to 30 are for uncompressed public key, but 31 to 34 for compressed one. For better support for EVM on EOSIO, what about recovering an uncompressed public key (public key point) in case of recover ID 27-30? For this, it needs to merge implementation for missing serialize_ecc_point(). (EOSIO/fc#215)

[conr2d]

@heifner Thank you for the review. What do you think of recovering uncompressed public key for recovery ID from 27 to 30?

[heifner]

@heifner Thank you for the review. What do you think of recovering uncompressed public key for recovery ID from 27 to 30?

Sorry for the slow response. At this time we would like the uncompressed public key (if added) to come in under a different PR to keep this particular change focused on just having a recover key that does not assert.