---
$schema: https://json-schema.org/draft/2020-12/schema

allOf:
  - $ref: core-event-schema/event.yaml

description: |-
  This event type is used to exchange keys for end-to-end encryption.
  It is encrypted as an `m.room.encrypted` event using [Olm](/client-server-api/#molmv1curve25519-aes-sha2),
  then sent as a [to-device](/client-server-api/#send-to-device-messaging) event.
properties:
  content:
    properties:
      algorithm:
        type: string
        enum: ["m.megolm.v1.aes-sha2"]
        description: |-
          The encryption algorithm the key in this event is to be used with.
      room_id:
        type: string
        description: The room where the key is used.
      session_id:
        type: string
        description: The ID of the session that the key is for.
      session_key:
        type: string
        description: The key to be exchanged.
      shared_history:
        x-addedInMatrixVersion: "1.19"
        type: boolean
        description: |
          `true` indicates that the creator of this encryption considers that
          the session is [shareable](/client-server-api/#shareable-encryption-sessions):
          in other words, the sender has observed that the [room history
          visibility](/client-server-api/#room-history-visibility) is set to
          `shared` or `world_readable`, and that they understand and agree that
          the session keys may be shared with newly-invited users in future.

          Absence, or any other value, indicates that the creator of the
          session does not consider the session to be shareable.
    required:
      - algorithm
      - room_id
      - session_id
      - session_key
    type: object
  type:
    enum:
      - m.room_key
    type: string
type: object