2021 Sprint 10 2021.05.18 - 2021.05.31

Retrospective pad: https://pad.riseup.net/p/mIzcb7LwolQOdUze5BYe

During this sprint we will:

• Continue working on Transaction v5 support by:
  • implementing the consensus checks required for semantic validation and,
  • contextual verification of transaction v5, as well as
  • Storing transaction v5 Orchard nullifiers in the finalized state.
• Implement Block Header Chain History Commitment to finish ZIP-221 implementation and as a prerequisite for adding the transaction authorization hash to the block header commitment field and finishing ZIP-244 implementation.
• Finish implementation for ZIP-244 by
  • refactoring our existing code to make our transaction hash merkle tree implementation generic to be used over the 3 different hash types for sprout, sapling and orchard,
  • implementing or integrating the new sighash transaction digest algorithm specified in ZIP-244, and
  • adding the transaction authorization hash to the block header commitment field.
• Continue working on Zebra security fixes to mitigate distributed denial of service risk by:
  • Ignoring far-future untrusted_last_seen_times in peer address requests
  • Improving the accuracy of last seen times when gossiping peer addresses
  • Not gossiping unreachable peer addresses