/** * # HCS Topic Information * The current network state of an Hedera Consensus Service (HCS) Topic. * * ### Keywords * The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", * "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this * document are to be interpreted as described in [RFC2119](https://www.ietf.org/rfc/rfc2119) * and clarified in [RFC8174](https://www.ietf.org/rfc/rfc8174). */ syntax = "proto3"; package proto; // SPDX-License-Identifier: Apache-2.0 import "services_basic_types.proto"; import "services_custom_fees.proto"; option java_package = "com.hederahashgraph.api.proto.java"; // <<>> This comment is special code for setting PBJ Compiler java package option java_multiple_files = true; /** * Representation of an Hedera Consensus Service(HCS) topic. * * As with all network entities, a topic has a unique entity number, which is * usually given along with the network's shard and realm in the form of a * shard.realm.number id.
* An HCS topic is an ordered logical stream of messages united and secured by * a running hash of those messages. The integrity of any message on a topic, * and the topic stream as a whole, can always be ascertained from block stream * data by recomputing the running hash across any subset of messages on the * topic.
* The messages on a topic SHALL NOT be stored in network state, but are * available in the network block stream, and may be queried via the * Mirror Node system. */ message Topic { /** * The topic's ID. *

* This value SHALL be unique within the network. */ TopicID topic_id = 1; /** * The number of messages sent to the topic. */ int64 sequence_number = 2; /** * The expiration time for this topic, in seconds since the epoch. *

* For this purpose, `epoch` SHALL be the UNIX epoch with 0 at `1970-01-01T00:00:00.000Z`. */ int64 expiration_second = 3; /** * The number of seconds for which the topic will be automatically renewed * upon expiring (if it has a valid auto-renew account). */ int64 auto_renew_period = 4; /** * The id of the account (if any) that the network will attempt to charge * fees to complete auto-renewal of this topic, upon expiration. */ AccountID auto_renew_account_id = 5; /** * A flag indicating that this topic is deleted. */ bool deleted = 6; /** * The current running hash of this topic. *

* This 48-byte field is the output of a SHA-384 digest with input data * determined by the current version of the running hash algorithm used * by the network.
* All topics in state SHALL use running hash algorithm version `3`.
* The bytes of each uint64 or uint32 encoded for the hash input MUST be in * Big-Endian format. *

*

* If the algorithm version is '3', then the input data to the SHA-384 * digest are, in order: *
    *
  1. The previous running hash of the topic (48 bytes)
    2. *
  2. The `topicRunningHashVersion` (8 bytes)
    3. *
  3. The payer account's shard (8 bytes)
    4. *
  4. The payer account's realm (8 bytes)
    5. *
  5. The payer account's number (8 bytes)
    6. *
  6. The topic's shard (8 bytes)
    7. *
  7. The topic's realm (8 bytes)
    8. *
  8. The topic's number (8 bytes)
    9. *
  9. The number of seconds since the epoch when the * `ConsensusSubmitMessage` reached consensus (8 bytes)
    10. *
  10. The number of nanoseconds within the second when the * `ConsensusSubmitMessage` reached consensus (4 bytes)
    11. *
  11. The `topicSequenceNumber` (8 bytes)
    12. *
  12. The output of a SHA-384 digest of the message bytes from the * `ConsensusSubmitMessage` (48 bytes)
    13. *
*
Note that older messages on a topic, which are available in * the block stream, MAY use older algorithm versions, and the block stream * record incorporates a running hash version field to ensure the correct * hash calculation for each such historical message.
*/ bytes running_hash = 7; /** * A short description of this topic. *

* This value, if set, MUST NOT exceed `transaction.maxMemoUtf8Bytes` * (default 100) bytes when encoded as UTF-8. */ string memo = 8; /** * Access control for modification of the topic. *

* If this field is set, that key MUST sign each message to update or delete * this topic.
* A topic without an admin key SHALL be immutable, except for expiration * and renewal.
* If this field is not set, the `auto_renew_account_id` MUST NOT be set. */ Key admin_key = 9; /** * Access control for message submission to the topic. *

* If this field is set, that key MUST sign each consensus submit message * for this topic. */ Key submit_key = 10; /** * Access control for update/delete of custom fees. *

* If this field is unset, the current custom fees CANNOT be changed.
* If this field is set, that `Key` MUST sign any transaction to update * the custom fee schedule for this topic. */ Key fee_schedule_key = 11; /** * A set of "privileged payer" keys
* Keys in this list are permitted to submit messages to this topic without * paying custom fees associated with this topic. *

* If a submit transaction is signed by _any_ key included in this set, * custom fees SHALL NOT be charged for that transaction.
* A `fee_exempt_key_list` MUST NOT contain more than * `MAX_ENTRIES_FOR_FEE_EXEMPT_KEY_LIST` keys.
* A `fee_exempt_key_list` MUST NOT contain any duplicate keys.
* A `fee_exempt_key_list` MAY contain keys for accounts that are inactive, * deleted, or non-existent. * If not set, there SHALL NOT be any fee-exempt keys. In particular, the * following keys SHALL NOT be implicitly or automatically added to this * list: `adminKey`, `submitKey`, `fee_schedule_key`. */ repeated Key fee_exempt_key_list = 12; /** * A set of custom fee definitions.
* These are fees to be assessed for each submit to this topic. *

* If this list is empty, the only fees charged for a submit to this * topic SHALL be the network and node fees.
* If this list is not empty, each fee defined in this set SHALL * be evaluated for each message submitted to this topic, and the * resultant total assessed fees SHALL be charged.
* If this list is not empty, custom fees defined here SHALL be * charged _in addition to_ the base network and node fees. */ repeated FixedCustomFee custom_fees = 13; }