Proposed summary of impending breaking changes.

The goal is to get as many of the breaking data structure changes into the next breaking release as possible :)

• Change all RIPEMD160 to SHA256[:20]

  • Tx and Validator hashing - types: update tx hash to use SHA256 and no amino #1547, WIP Bucky/hash #1606
  • IAVL (doesn't effect Tendermint)
  • ED25519 address generation - PR update ed25519 address scheme go-crypto#112

• Don't Amino encode basic byte arrays before hashing

  • Txs - types: update tx hash to use SHA256 and no amino #1547
  • pubkeys when computing addresses - tendermint/go-crypto/pubkey based p2p handshake because ips are flaky #103, PR update ed25519 address scheme go-crypto#112

• Proposals/Votes - consensus: spec and impl for BFT time #1146, WIP Jae/bft time #1615

  • don't sign Timestamp
  • instead, we can do BFT time just through the proposer Jae/bft time #1615

• Header

  • Add proposer (and round?) - Add proposer to header #1134
  • Add tags to results hash - Add events to results hash #1007
  • NextValSetHash - NextValidatorSetHash #1313, WIP WIP: Delaying a validator set update by 1 block. #1638

• ABCI

  • AbsentValidators should be a list of addresses, not indices
  • Update header
  • Include Round number in BeginBlock (possibly in header as "LastCommitRound" ? )
  • Begin/EndBlock tags - Add tags to Begin/Endblock and support subscriptions to them #915
  • ResponseInitChain takes GenesisBytes instead of AppStateBytes - Extend RequestInitChain to contain the entire genesis.json file abci#216

• Validator set changes

  • Validators only change at H+2 - NextValidatorSetHash #1313 , WIP WIP: Delaying a validator set update by 1 block. #1638

• P2P

  • Update SecretConnection - Improve SecretConnection/STS KDF? #1165, Use ChaCha20Poly1305 instead of Salsa20Poly1305 for SecretConnection? #1124, WIP BREAKING CHANGE Replaces hash based key derivation with hkdf  #1563
  • Add ValidatorAddress to NodeInfo - p2p: add UnverifiedValidatorAddress to the NodeInfo #1516, WIP (BREAKING) p2p: add UnverifiedValidatorAddress to the NodeInfo #1604
  • pubkey -> id in p2p query