> ## Documentation Index > Fetch the complete documentation index at: https://docs.bastion.com/llms.txt > Use this file to discover all available pages before exploring further. # Rotate Webhook Signing Key > Generate or rotate the HMAC signing secret for a webhook endpoint. If the webhook already has a key, the existing key is moved into a 'previous' slot and remains valid for the overlap window (24H) during which deliveries carry both signatures. The new secret is returned exactly once. ## OpenAPI ````yaml /v2/openapi.yaml post /v2/webhooks/{id}/rotate-signing-key openapi: 3.1.0 info: title: Bastion APIs version: '2.0' servers: - url: https://api.prod.bastion.com description: Production environment - url: https://api.sandbox.bastion.io description: Sandbox environment security: - auth: [] tags: - name: Bastion APIs paths: /v2/webhooks/{id}/rotate-signing-key: post: tags: - Webhooks summary: Rotate Webhook Signing Key description: |- Generate or rotate the HMAC signing secret for a webhook endpoint. If the webhook already has a key, the existing key is moved into a 'previous' slot and remains valid for the overlap window (24H) during which deliveries carry both signatures. The new secret is returned exactly once. operationId: bastion.api.v2.API.RotateWebhookSigningKey parameters: - name: id in: path description: The ID of the webhook to rotate the signing key for required: true schema: type: string title: id responses: '200': description: Success content: application/json: schema: $ref: >- #/components/schemas/bastion.api.v2.RotateWebhookSigningKeyResponse '400': description: Bad request '404': description: Webhook not found '500': description: Internal Server Error components: schemas: bastion.api.v2.RotateWebhookSigningKeyResponse: type: object properties: signing_secret: type: string title: signing_secret description: Plaintext signing secret. Returned exactly once — store it now. readOnly: true key_id: type: string title: key_id description: Opaque identifier for this key readOnly: true previous_key_expires_at: $ref: '#/components/schemas/google.protobuf.Timestamp' title: previous_key_expires_at description: When the previous key stops being valid. Empty on first generate. readOnly: true title: RotateWebhookSigningKeyResponse additionalProperties: false google.protobuf.Timestamp: type: string examples: - '2023-01-15T01:30:15.01Z' - '2024-12-25T12:00:00Z' format: date-time description: >- A Timestamp represents a point in time independent of any time zone or local calendar, encoded as a count of seconds and fractions of seconds at nanosecond resolution. The count is relative to an epoch at UTC midnight on January 1, 1970, in the proleptic Gregorian calendar which extends the Gregorian calendar backwards to year one. All minutes are 60 seconds long. Leap seconds are "smeared" so that no leap second table is needed for interpretation, using a [24-hour linear smear](https://developers.google.com/time/smear). The range is from 0001-01-01T00:00:00Z to 9999-12-31T23:59:59.999999999Z. By restricting to that range, we ensure that we can convert to and from [RFC 3339](https://www.ietf.org/rfc/rfc3339.txt) date strings. # Examples Example 1: Compute Timestamp from POSIX `time()`. Timestamp timestamp; timestamp.set_seconds(time(NULL)); timestamp.set_nanos(0); Example 2: Compute Timestamp from POSIX `gettimeofday()`. struct timeval tv; gettimeofday(&tv, NULL); Timestamp timestamp; timestamp.set_seconds(tv.tv_sec); timestamp.set_nanos(tv.tv_usec * 1000); Example 3: Compute Timestamp from Win32 `GetSystemTimeAsFileTime()`. FILETIME ft; GetSystemTimeAsFileTime(&ft); UINT64 ticks = (((UINT64)ft.dwHighDateTime) << 32) | ft.dwLowDateTime; // A Windows tick is 100 nanoseconds. Windows epoch 1601-01-01T00:00:00Z // is 11644473600 seconds before Unix epoch 1970-01-01T00:00:00Z. Timestamp timestamp; timestamp.set_seconds((INT64) ((ticks / 10000000) - 11644473600LL)); timestamp.set_nanos((INT32) ((ticks % 10000000) * 100)); Example 4: Compute Timestamp from Java `System.currentTimeMillis()`. long millis = System.currentTimeMillis(); Timestamp timestamp = Timestamp.newBuilder().setSeconds(millis / 1000) .setNanos((int) ((millis % 1000) * 1000000)).build(); Example 5: Compute Timestamp from Java `Instant.now()`. Instant now = Instant.now(); Timestamp timestamp = Timestamp.newBuilder().setSeconds(now.getEpochSecond()) .setNanos(now.getNano()).build(); Example 6: Compute Timestamp from current time in Python. timestamp = Timestamp() timestamp.GetCurrentTime() # JSON Mapping In JSON format, the Timestamp type is encoded as a string in the [RFC 3339](https://www.ietf.org/rfc/rfc3339.txt) format. That is, the format is "{year}-{month}-{day}T{hour}:{min}:{sec}[.{frac_sec}]Z" where {year} is always expressed using four digits while {month}, {day}, {hour}, {min}, and {sec} are zero-padded to two digits each. The fractional seconds, which can go up to 9 digits (i.e. up to 1 nanosecond resolution), are optional. The "Z" suffix indicates the timezone ("UTC"); the timezone is required. A ProtoJSON serializer should always use UTC (as indicated by "Z") when printing the Timestamp type and a ProtoJSON parser should be able to accept both UTC and other timezones (as indicated by an offset). For example, "2017-01-15T01:30:15.01Z" encodes 15.01 seconds past 01:30 UTC on January 15, 2017. In JavaScript, one can convert a Date object to this format using the standard [toISOString()](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Date/toISOString) method. In Python, a standard `datetime.datetime` object can be converted to this format using [`strftime`](https://docs.python.org/2/library/time.html#time.strftime) with the time format spec '%Y-%m-%dT%H:%M:%S.%fZ'. Likewise, in Java, one can use the Joda Time's [`ISODateTimeFormat.dateTime()`]( http://joda-time.sourceforge.net/apidocs/org/joda/time/format/ISODateTimeFormat.html#dateTime() ) to obtain a formatter capable of generating timestamps in this format. securitySchemes: auth: type: http description: Bearer authentication with an API token scheme: bearer ```` ## Related topics - [Verifying Bastion webhook signatures](/v2/api-reference/webhooks/verifying-bastion-webhooks.md) - [API authentication overview](/guides/security/api-authentication.md) - [List Webhooks](/v2/api-reference/webhooks/list-webhooks.md) - [Create Webhook](/v2/api-reference/webhooks/create-webhook.md) - [Register Signing Key](/v2/api-reference/signing-keys/register-signing-key.md)