Обзор по интеграции#

This documentation is also available as a PDF.

Dash Core is a fork of Bitcoin Core and shares many common functionalities. Key differences are found in existing JSON-RPC commands which have been customized to support unique functionalities such as InstantSend.

The Basics#

Dash is a Proof of Work network, and similar to Bitcoin, Dash has a mining network but uses a different block hashing algorithm. Dash serves as an improvement of Bitcoin’s shortcomings by offering a robust solution for instant transactions, enhancing user privacy, and offering a self-sustainable decentralized governance model.

Notably, Dash InstantSend provides a mechanism for zero-confirmation transactions to be safely accepted and re-spent. InstantSend also provides enhanced security compared to the conventional practice of waiting for multiple block confirmations. Therefore, implementing InstantSend is the recommended best practice for all Dash integrations.

JSON-RPC Interface#

The majority of commands are unchanged from Bitcoin making integration into existing systems relatively straightforward. For a complete listing of RPC commands please refer to the ​Dash Developer Guide.

Note that the following commands have been modified to support InstantSend:

Специальные транзакции#

Dash Core v0.13.0 introduced the concept of “Special Transactions” as specified in DIP002. Special Transactions provide a more native way to implement additional features which do not fit into the original concept of transactions. Please see the Special Transactions section below for more information.

Block Hashing Algorithm#

Dash uses the X11 algorithm in place of SHA256 used in Bitcoin. It’s important to note, however, that this only affects the hashing of the block itself. All other internals utilize SHA256 hashes (transactions, merkle root, etc.), which allows for most existing libraries to work in the Dash ecosystem.

Специальные транзакции#

This documentation is also available as a PDF.

Dash 0.13.0 and higher implement DIP002 Special Transactions, which form a basis for new transaction types that provide on-chain metadata to assist various consensus mechanisms. The following special transaction types exist:

Версия

Тип

Размер нагрузки

Transaction Purpose / Example

3

0

n/a

Стандартная транзакция

3

1

variable

Masternode Registration

3

2

variable

Update Masternode Service

3

3

variable

Update Masternode Operator

3

4

variable

Masternode Revocation

3

5

variable

Masternode List Merkle Proof

3

6

variable

Quorum Commitment

Примечания по интеграции:

  1. DIP002 Special Transactions introduced a new Transaction Version and related “Payload” to the network.

  2. Integrated Systems must be able to serialize and deserialize these new Transaction Types to accurately encode and decode Raw Transaction data.

  3. From a backwards compatibility perspective, the 4 byte (32-bit) version field included in Classical Transactions was split into two fields: version and type (each consisting of 2 bytes).

  4. Refer to the Special Transactions section of the Dash developer reference for additional detail on these data types, e.g. <variable int>.

  5. InstantSend status and Payload JSON (e.g. proRegTx) is included in the JSON-RPC response, please note that this data is not part of the calculated hash and is provided for convenience.

See the transaction types integration documentation (PDF) for worked examples of each transaction type.

InstantSend#

This documentation is also available as a PDF.

InstantSend is a feature provided by the Dash network that allows for zero-confirmation transactions to be safely accepted and re-spent. The network attempts to lock the inputs of every valid transaction when it is broadcast to the network. Every secured transaction is included in a following block in accordance with standard blockchain principles. Transactions are typically locked by InstantSend within 3 seconds of being propagated to the network.

InstantSend is enabled by the Masternode Network which comprises several thousand masternode servers. These nodes are differentiated from standard nodes by having proven ownership of 1,000 Dash, making the network highly resistant to Sybil attacks. Masternodes form Long-Living Masternode Quorums (LLMQs), which are responsible for providing near-instant certainty to the transaction participants that the transaction inputs cannot be re-spent, and that the transaction will be included in a following block instead of a conflicting transaction.

This concept works as an extension to Nakamoto Consensus to provide additional security. InstantSend enables transacted funds to be immediately and securely re-spent by the recipient, even before the transaction is included in a block.

Получение транзакций InstantSend#

Примечание

An «InstantSend Transaction» is simply a standard transaction that has been provided additional assurances by the masternode network. As a result, and from an integration perspective, the only technical difference is the InstantSend status.

Вводится два требования для получения транзакций InstantSend:

  1. Возможность определить «статус InstantSend» в заданной транзакции.

  2. Возможность настройки «статуса подтверждения» независимо от подтверждения блока.

InstantSend Status обычно определяется через прямое соединение с демоном dash, уведомление ZMQ, или с помощью сценария уведомления внешнего кошелька.

Direct Connection#

InstantSend Status can be identified through direct connection with the Dash daemon using JSON-RPC protocol. The instantlock attribute of the JSON response reflects the status of the transaction and is included in the following commands:

ZMQ Notification#

Whenever a transaction enters the mempool and whenever a transaction is locked in the mempool, ZMQ notifications can be broadcast by the node. A list of possible ZMQ notifications can be found here.

The following notifications are relevant for recognizing transactions and their corresponding instantlocks:

  • zmqpubhashtx

  • zmqpubhashtxlock

  • zmqpubrawtx

  • zmqpubrawtxlock

Wallet Notification#

The Dash Core Daemon can be configured to execute an external script whenever an InstantSend transaction relating to that wallet is observed. This is configured by adding the following line to the dash.conf file:

instantsendnotify=/path/to/concurrent/safe/handler %s

This is typically used with a wallet that has been populated with watch-only addresses.

Распространение транзакций InstantSend#

Совет

Because all transactions on the Dash network are automatically InstantSend, no procedural changes are required to broadcast transactions as InstantSend.

Since Dash v0.14.0 established LLMQs on the Dash network, quorums will now attempt to lock every valid transaction by default without any additional fee or action by the sending wallet or user. A transaction is eligible for InstantSend when each of its inputs is considered confirmed. This is the case when at least one of the following circumstances is true:

  • the previous transaction referred to by the input is confirmed with 6 blocks

  • the previous transaction is confirmed through an older InstantSend lock

  • the block containing the previous transaction is ChainLocked

When checking the previous transaction for an InstantSend lock, it is important to do this on mempool (non-mined) transactions. This allows chained InstantSend locking.

Дополнительные ресурсы#

Следующие ресурсы предоставляют дополнительную информацию о функции InstantSend и предназначены для обеспечения более полного понимания базовых технологий.