package protobuf

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Branch will hash data and then pass it through operations from first to last in order to calculate the root node. Visualize Branch as representing the data closest to root as the first item, and the leaf as the last item.

Used in: MerkleProof

• bytes prefixLeaf = 1

  if either are non-empty, enforce this prefix on all leaf/inner nodes to provide second preimage resistence

• bytes prefixInner = 2

• optional Data data = 3

  this is the data to get the original hash, and a set of operations to calculate the root hash

• repeated Op operations = 4

Data is the end value stored, used to generate the initial hash store

Used in: Branch

• bytes prefix = 1

  optional prefix allows second preimage resistance

• bytes key = 2

• bytes value = 3

• HashOp op = 4

• Data.DataType dataType = 5

If it is KeyValue, this is the data we want If it is SubTree, key is name of the tree, value is root hash

Used in: Data

• KeyValue = 0

• SubTree = 1

HashOp is the hashing algorithm we use at each level

Used in: Data, Op

• RIPEMD160 = 0

• SHA224 = 1

• SHA256 = 2

• SHA384 = 3

• SHA512 = 4

• SHA3_224 = 5

• SHA3_256 = 6

• SHA3_384 = 7

• SHA3_512 = 8

• SHA256_X2 = 9

IBCPacket sends a proven key/value pair from an IBCQueue. Depending on the type of message, we require a certain type of key (MessageKey at a given height, or StateKey). Includes src_chain and src_height to look up the proper header to verify the merkle proof.

• string src_chain = 1

  chain id it is coming from

• uint64 src_height = 2

  height for the header the proof belongs to

• IBCPacket.MsgType msgType = 3

• optional MerkleProof proof = 6

  the proof of the message, includes key and value

the message type, which determines what key/value mean

Used in: IBCPacket

• RECEIVE = 0

• RECEIPT = 1

• TIMEOUT = 2

• CLEANUP = 3

TODO: root, height, chain_id, etc...

Used in: IBCPacket

• repeated Branch branches = 1

  branches start from the value, and then may include multiple subtree branches to embed it The first branch must have dataType KeyValue Following branches must have dataType SubTree

MessageKey is the key for message *index* in a given queue

• optional QueueName queue = 1

• fixed64 index = 2

Op represents one hash in a chain of hashes. An operation takes the output of the last level and returns a hash for the next level: Op(last) => Operation(prefix + last + sufix) A simple left/right hash would simply set prefix=left or suffix=right and leave the other blank. However, one could also represent the a Patricia trie proof by setting prefix to the rlp encoding of all nodes before the branch we select, and suffix to all those after the one we select.

Used in: Branch

• bytes prefix = 1

• bytes suffix = 2

• HashOp op = 3

Used in: MessageKey, StateKey

• string chain_id = 1

  chain_id is which chain this queue is associated with

• QueueName.Purpose purpose = 2

Used in: QueueName

• SEND = 0

• RECEIPT = 1

ReceiptValue is stored under a MessageKey in the RECEIPT queue

• int32 errorCode = 1

  0 is success, others are application-defined errors

• bytes data = 2

  contains result on success, optional info on error

SendValue is stored under a MessageKey in the SEND queue

• uint64 maxHeight = 1

• optional google.protobuf.Timestamp maxTime = 2

• bytes kind = 3

  use kind instead of type to avoid keyword conflict

• bytes data = 4

StateKey is a key for the head/tail of a given queue

• optional QueueName queue = 1

• StateKey.State state = 2

both encode into one byte with varint encoding never clash with 8 byte message indexes

Used in: StateKey

• HEAD = 0

• TAIL = 127

StateValue is the type stored under a StateKey

• fixed64 index = 1