Initial feedback received from CypherStack for the latest blockstream BP++ paper:
There are several aspects of the preprint that should be considered out of scope for a review:
- Multiparty computation. There are no specific protocols presented for this, and no corresponding security model of proofs of security.
- Batch verification. While the preprint mentions that BP++ supports batch verification, it provides no details on the corresponding algebra.
- Multi-asset transactions. The preprint discusses multi-asset transactions in the context of its protocols, but these are not required for range proofs.
- Optimized binary range proofs. The protocol proposed for optimized binary range proofs has only an informal and vague security proof that is insufficient to assert the claims of the corresponding theorem.