> ## Documentation Index
> Fetch the complete documentation index at: https://docs.hedera.com/llms.txt
> Use this file to discover all available pages before exploring further.

# ConsensusTopicInfo

| Field              | Type                                                       | Description                                                                                                                                                                                                                                                                                                                                                                                                           |
| ------------------ | ---------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `memo`             | ​                                                          | Short publicly visible memo about the topic. No guarantee of uniqueness.                                                                                                                                                                                                                                                                                                                                              |
| `runningHash`      | ​                                                          | <p>When a topic is created, its running hash is initialized to 48 bytes of binary zeros. For each submitted message, the topic’s running hash is then updated to the output of a particular SHA-384 digest whose input data include the previous running hash.<br /><br />See the TransactionReceipt.proto documentation for an exact description of the data included in the SHA-384 digest used for the update.</p> |
| `sequenceNumber`   |                                                            | Sequence number (starting at 1 for the first submitMessage) of messages on the topic.                                                                                                                                                                                                                                                                                                                                 |
| `expirationTime`   | ​[Timestamp](/reference/protobuf/miscellaneous/timestamp)​ | Effective consensus timestamp at (and after) which submitMessage calls will no longer succeed on the topic and the topic will expire and after AUTORENEW\_GRACE\_PERIOD be automatically deleted.                                                                                                                                                                                                                     |
| `adminKey`         | ​[Key](/reference/protobuf/basic-types/key)​               | Access control for update/delete of the topic. Null if there is no key.                                                                                                                                                                                                                                                                                                                                               |
| `submitKey`        | ​[Key](/reference/protobuf/basic-types/key)​               | Access control for ConsensusService.submitMessage. Null if there is no key.                                                                                                                                                                                                                                                                                                                                           |
| `autoRenewPeriod`  | ​[Duration](/reference/protobuf/miscellaneous/duration)​   | The duration in which to renew the topic                                                                                                                                                                                                                                                                                                                                                                              |
| `autoRenewAccount` | ​[AccountID](/reference/protobuf/basic-types/accountid)​   | Null if there is no autoRenewAccount.                                                                                                                                                                                                                                                                                                                                                                                 |
| `ledger_id`        | bytes                                                      | The ledger ID the response was returned from; please see [HIP-198](https://github.com/hashgraph/hedera-improvement-proposal/blob/master/HIP/hip-198.md) for the network-specific IDs.                                                                                                                                                                                                                                 |