# EPF Cohort 6 - Week 12 Update

As I am taking up a lot of the work related to Post Quantum signatures on Ream, this weeks calls had a lot of new research that I will be integrating over the upcoming weeks.

This week I attended the pq interop call \#9 which covered a presentation on the leanMultisig specs by Thomas Cotrager and the lean consensus call \#7 which covered the Lean Consensus PQ Subspec. Following this call I updated the leanroadmap.org website with all the available resources discussed in the call.

I also created a PR for private key generation and I am working on a PR to create a modular signature scheme in my HashSig interface.

## Week 12

### PQ Interop Meeting 8

Thomas presented the leanMultiSig specs in this call. I shall link my notes on this call in the references shortly. The main outcomes for me from this call were the representation of PQ Signatures (containing path, rho and hashes) and the release of the Prod and Test signature schemes. I shall start benchmarking key generation times with these schemes later this week.

    PROD_CONFIG: Final = XmssConfig(
        MESSAGE_LENGTH=32,
        LOG_LIFETIME=32,
        DIMENSION=64,
        BASE=8,
        FINAL_LAYER=77,
        TARGET_SUM=375,
        MAX_TRIES=100_000,
        PARAMETER_LEN=5,
        TWEAK_LEN_FE=2,
        MSG_LEN_FE=9,
        RAND_LEN_FE=7,
        HASH_LEN_FE=8,
        CAPACITY=9,
        POS_OUTPUT_LEN_PER_INV_FE=15,
        POS_INVOCATIONS=1,
)

### PRs for Key generation

As the node identities for all the nodes participating the PQ Devnet will be pre-generated we want the Ream CLI to be able to generate a secp256k1 keypair as well as use a pre-genererated keypair for libp2p. I implemented creating the keypair using the following command:

cargo run generate_network_key --output-path ./my_network_key

We can then use this or any other protobuf encoded keypair in the node with the following command:

cargo run lean_node --secret-key-path ./my_network_key

### WIP PR on HashSig Signature Schemes

When I implemented the HashSig interface I defaulted the XMSS Signature Scheme to `SIGWinternitzLifetime18W4` from the hash-sig crate. However as the new PQ Subspecs define the schemes that will be used in test and production, I have to change this to be easily swappable.

This will also allow us to easily benchmark different signature schemes. I have started working on this and will have a PR up for it this week.

## Resources

1. [Keypair for libp2p PR](https://github.com/ReamLabs/ream/pull/781)
2. [Issue for Modular HashSigScheme](https://github.com/ReamLabs/ream/issues/771)
3. [Lean XMSS Specs](https://github.com/leanEthereum/leanSpec/tree/main/src/lean_spec/subspecs/xmss)
5. [PQ Interop Meeting 8 Agenda](https://github.com/ethereum/pm/issues/1712)
6. [PQ Interop Meeting 8 Recording](https://www.youtube.com/watch?v=buacaj50n_Y)