Protocol Documentation

Table of Contents

compact_formats.proto

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CompactBlock

CompactBlock is a packaging of ONLY the data from a block that's needed to:

1. Detect a payment to your shielded Sapling address

2. Detect a spend of your shielded Sapling notes

3. Update your witnesses to generate new Sapling spend proofs.

FieldTypeLabelDescription
protoVersion uint32

the version of this wire format, for storage

height uint64

the height of this block

hash bytes

the ID (hash) of this block, same as in block explorers

prevHash bytes

the ID (hash) of this block's predecessor

time uint32

Unix epoch time when the block was mined

header bytes

(hash, prevHash, and time) OR (full header)

vtx CompactTx repeated

zero or more compact transactions from this block

CompactOutput

output is a Sapling Output Description as described in section 7.4 of the

Zcash protocol spec. Total size is 948.

FieldTypeLabelDescription
cmu bytes

note commitment u-coordinate

epk bytes

ephemeral public key

ciphertext bytes

ciphertext and zkproof

CompactSpend

CompactSpend is a Sapling Spend Description as described in 7.3 of the Zcash

protocol specification.

FieldTypeLabelDescription
nf bytes

nullifier (see the Zcash protocol specification)

CompactTx

CompactTx contains the minimum information for a wallet to know if this transaction

is relevant to it (either pays to it or spends from it) via shielded elements

only. This message will not encode a transparent-to-transparent transaction.

FieldTypeLabelDescription
index uint64

the index within the full block

hash bytes

the ID (hash) of this transaction, same as in block explorers

fee uint32

The transaction fee: present if server can provide. In the case of a stateless server and a transaction with transparent inputs, this will be unset because the calculation requires reference to prior transactions. in a pure-Sapling context, the fee will be calculable as: valueBalance + (sum(vPubNew) - sum(vPubOld) - sum(tOut))

spends CompactSpend repeated

inputs

outputs CompactOutput repeated

outputs

darkside.proto

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DarksideBlock

A block is a hex-encoded string.

FieldTypeLabelDescription
block string

DarksideBlocksURL

DarksideBlocksURL is typically something like:

https://raw.githubusercontent.com/zcash-hackworks/darksidewalletd-test-data/master/basic-reorg/before-reorg.txt

FieldTypeLabelDescription
url string

DarksideEmptyBlocks

FieldTypeLabelDescription
height int32

nonce int32

count int32

DarksideHeight

FieldTypeLabelDescription
height int32

DarksideMetaState

FieldTypeLabelDescription
saplingActivation int32

branchID string

chainName string

DarksideTransactionsURL

DarksideTransactionsURL refers to an HTTP source that contains a list

of hex-encoded transactions, one per line, that are to be associated

with the given height (fake-mined into the block at that height)

FieldTypeLabelDescription
height int32

url string

DarksideStreamer

Darksidewalletd maintains two staging areas, blocks and transactions. The

Stage*() gRPCs add items to the staging area; ApplyStaged() "applies" everything

in the staging area to the working (operational) state that the mock zcashd

serves; transactions are placed into their corresponding blocks (by height).

Method NameRequest TypeResponse TypeDescription
Reset DarksideMetaState Empty

Reset reverts all darksidewalletd state (active block range, latest height, staged blocks and transactions) and lightwalletd state (cache) to empty, the same as the initial state. This occurs synchronously and instantaneously; no reorg happens in lightwalletd. This is good to do before each independent test so that no state leaks from one test to another. Also sets (some of) the values returned by GetLightdInfo(). The Sapling activation height specified here must be where the block range starts.

StageBlocksStream DarksideBlock stream Empty

StageBlocksStream accepts a list of blocks and saves them into the blocks staging area until ApplyStaged() is called; there is no immediate effect on the mock zcashd. Blocks are hex-encoded. Order is important, see ApplyStaged.

StageBlocks DarksideBlocksURL Empty

StageBlocks is the same as StageBlocksStream() except the blocks are fetched from the given URL. Blocks are one per line, hex-encoded (not JSON).

StageBlocksCreate DarksideEmptyBlocks Empty

StageBlocksCreate is like the previous two, except it creates 'count' empty blocks at consecutive heights starting at height 'height'. The 'nonce' is part of the header, so it contributes to the block hash; this lets you create identical blocks (same transactions and height), but with different hashes.

StageTransactionsStream RawTransaction stream Empty

StageTransactionsStream stores the given transaction-height pairs in the staging area until ApplyStaged() is called. Note that these transactions are not returned by the production GetTransaction() gRPC until they appear in a "mined" block (contained in the active blockchain presented by the mock zcashd).

StageTransactions DarksideTransactionsURL Empty

StageTransactions is the same except the transactions are fetched from the given url. They are all staged into the block at the given height. Staging transactions to different heights requires multiple calls.

ApplyStaged DarksideHeight Empty

ApplyStaged iterates the list of blocks that were staged by the StageBlocks*() gRPCs, in the order they were staged, and "merges" each into the active, working blocks list that the mock zcashd is presenting to lightwalletd. Even as each block is applied, the active list can't have gaps; if the active block range is 1000-1006, and the staged block range is 1003-1004, the resulting range is 1000-1004, with 1000-1002 unchanged, blocks 1003-1004 from the new range, and 1005-1006 dropped. After merging all blocks, ApplyStaged() appends staged transactions (in the order received) into each one's corresponding (by height) block The staging area is then cleared. The argument specifies the latest block height that mock zcashd reports (i.e. what's returned by GetLatestBlock). Note that ApplyStaged() can also be used to simply advance the latest block height presented by mock zcashd. That is, there doesn't need to be anything in the staging area.

GetIncomingTransactions Empty RawTransaction stream

Calls to the production gRPC SendTransaction() store the transaction in a separate area (not the staging area); this method returns all transactions in this separate area, which is then cleared. The height returned with each transaction is -1 (invalid) since these transactions haven't been mined yet. The intention is that the transactions returned here can then, for example, be given to StageTransactions() to get them "mined" into a specified block on the next ApplyStaged().

ClearIncomingTransactions Empty Empty

Clear the incoming transaction pool.

service.proto

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Address

FieldTypeLabelDescription
address string

AddressList

FieldTypeLabelDescription
addresses string repeated

Balance

FieldTypeLabelDescription
valueZat int64

BlockID

A BlockID message contains identifiers to select a block: a height or a

hash. Specification by hash is not implemented, but may be in the future.

FieldTypeLabelDescription
height uint64

hash bytes

BlockRange

BlockRange specifies a series of blocks from start to end inclusive.

Both BlockIDs must be heights; specification by hash is not yet supported.

FieldTypeLabelDescription
start BlockID

end BlockID

ChainSpec

Chainspec is a placeholder to allow specification of a particular chain fork.

Duration

Duration is currently used only for testing, so that the Ping rpc

can simulate a delay, to create many simultaneous connections. Units

are microseconds.

FieldTypeLabelDescription
intervalUs int64

Empty

Empty is for gRPCs that take no arguments, currently only GetLightdInfo.

Exclude

FieldTypeLabelDescription
txid bytes repeated

LightdInfo

LightdInfo returns various information about this lightwalletd instance

and the state of the blockchain.

FieldTypeLabelDescription
version string

vendor string

taddrSupport bool

true

chainName string

either "main" or "test"

saplingActivationHeight uint64

depends on mainnet or testnet

consensusBranchId string

protocol identifier, see consensus/upgrades.cpp

blockHeight uint64

latest block on the best chain

gitCommit string

branch string

buildDate string

buildUser string

PingResponse

PingResponse is used to indicate concurrency, how many Ping rpcs

are executing upon entry and upon exit (after the delay).

This rpc is used for testing only.

FieldTypeLabelDescription
entry int64

exit int64

RawTransaction

RawTransaction contains the complete transaction data. It also optionally includes

the block height in which the transaction was included.

FieldTypeLabelDescription
data bytes

exact data returned by zcash 'getrawtransaction'

height uint64

height that the transaction was mined (or -1)

SendResponse

A SendResponse encodes an error code and a string. It is currently used

only by SendTransaction(). If error code is zero, the operation was

successful; if non-zero, it and the message specify the failure.

FieldTypeLabelDescription
errorCode int32

errorMessage string

TransparentAddressBlockFilter

TransparentAddressBlockFilter restricts the results to the given address

or block range.

FieldTypeLabelDescription
address string

t-address

range BlockRange

start, end heights

TreeState

The TreeState is derived from the zcash z_gettreestate rpc.

FieldTypeLabelDescription
network string

"main" or "test"

height uint64

hash string

block id

time uint32

Unix epoch time when the block was mined

tree string

sapling commitment tree state

TxFilter

A TxFilter contains the information needed to identify a particular

transaction: either a block and an index, or a direct transaction hash.

Currently, only specification by hash is supported.

FieldTypeLabelDescription
block BlockID

block identifier, height or hash

index uint64

index within the block

hash bytes

transaction ID (hash, txid)

CompactTxStreamer

Method NameRequest TypeResponse TypeDescription
GetLatestBlock ChainSpec BlockID

Return the height of the tip of the best chain

GetBlock BlockID CompactBlock

Return the compact block corresponding to the given block identifier

GetBlockRange BlockRange CompactBlock stream

Return a list of consecutive compact blocks

GetTransaction TxFilter RawTransaction

Return the requested full (not compact) transaction (as from zcashd)

SendTransaction RawTransaction SendResponse

Submit the given transaction to the zcash network

GetTaddressTxids TransparentAddressBlockFilter RawTransaction stream

Return the txids corresponding to the given t-address within the given block range

GetTaddressBalance AddressList Balance

GetTaddressBalanceStream Address stream Balance

GetMempoolTx Exclude CompactTx stream

Return the compact transactions currently in the mempool; the results can be a few seconds out of date. If the Exclude list is empty, return all transactions; otherwise return all *except* those in the Exclude list (if any); this allows the client to avoid receiving transactions that it already has (from an earlier call to this rpc). The transaction IDs in the Exclude list can be shortened to any number of bytes to make the request more bandwidth-efficient; if two or more transactions in the mempool match a shortened txid, they are all sent (none is excluded). Transactions in the exclude list that don't exist in the mempool are ignored.

GetTreeState BlockID TreeState

GetTreeState returns the note commitment tree state corresponding to the given block. See section 3.7 of the zcash protocol specification. It returns several other useful values also (even though they can be obtained using GetBlock). The block can be specified by either height or hash.

GetLightdInfo Empty LightdInfo

Return information about this lightwalletd instance and the blockchain

Ping Duration PingResponse

Testing-only

Scalar Value Types

.proto TypeNotesC++JavaPythonGoC#PHPRuby
double double double float float64 double float Float
float float float float float32 float float Float
int32 Uses variable-length encoding. Inefficient for encoding negative numbers – if your field is likely to have negative values, use sint32 instead. int32 int int int32 int integer Bignum or Fixnum (as required)
int64 Uses variable-length encoding. Inefficient for encoding negative numbers – if your field is likely to have negative values, use sint64 instead. int64 long int/long int64 long integer/string Bignum
uint32 Uses variable-length encoding. uint32 int int/long uint32 uint integer Bignum or Fixnum (as required)
uint64 Uses variable-length encoding. uint64 long int/long uint64 ulong integer/string Bignum or Fixnum (as required)
sint32 Uses variable-length encoding. Signed int value. These more efficiently encode negative numbers than regular int32s. int32 int int int32 int integer Bignum or Fixnum (as required)
sint64 Uses variable-length encoding. Signed int value. These more efficiently encode negative numbers than regular int64s. int64 long int/long int64 long integer/string Bignum
fixed32 Always four bytes. More efficient than uint32 if values are often greater than 2^28. uint32 int int uint32 uint integer Bignum or Fixnum (as required)
fixed64 Always eight bytes. More efficient than uint64 if values are often greater than 2^56. uint64 long int/long uint64 ulong integer/string Bignum
sfixed32 Always four bytes. int32 int int int32 int integer Bignum or Fixnum (as required)
sfixed64 Always eight bytes. int64 long int/long int64 long integer/string Bignum
bool bool boolean boolean bool bool boolean TrueClass/FalseClass
string A string must always contain UTF-8 encoded or 7-bit ASCII text. string String str/unicode string string string String (UTF-8)
bytes May contain any arbitrary sequence of bytes. string ByteString str []byte ByteString string String (ASCII-8BIT)