Zebra v1.0.0-alpha.6

Zebra's latest alpha includes more validation of pre-NU5 consensus rules, continues our work on NU5/Orchard, and fixes some security and protocol correctness issues.

The Zebra project now has a Code of Conduct.

Added

• Design for Transaction V5 (#1886)
  • Make shielded data and spends generic over Transaction V4 and V5 (#1946, #1989)
• Async batching for:
  • Sprout JoinSplit signatures (#1952)
  • Sapling Spend and Output Groth16 proofs (#1713)
• Enable Joinsplit and Spend spend auth sighash verification (#1940)
• Randomised property tests for InventoryHash and MetaAddr (#1985)

Documentation

• Update the RFC process to include draft RFCs (#1962)
  • Merge some open RFCs as drafts (#1006, #1007, #1063, #1129)
• Add a fast start option to the Zebra Client RFC (#1969)
• Document that Zebra's mandatory checkpoint can change (#1935)

Changed

• Refactor the Block Commitment field based on ZIP-244 (#1957, #1978, #1988)

Fixed

• Stop ignoring inbound message errors and handshake timeouts (#1950)
• Don't send a useless heartbeat when the peer connection is already closing (#1950)

Security

• Reduce deserialized memory usage for malicious blocks (#1920, #1977)
• Ensure that new MetaAddr fields are sanitized (#1942)
• Fix a deadlock between the peer address crawler and peer dialer when all connections fail (#1950)
• Avoid starvation of handshakes and crawling under heavy syncer load (#1950)
• Avoid starvation of request cancellations and timeouts under heavy peer response load (#1950)
• Async network code correctness documentation (#1954, #1972)