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Shelter protocol

Invite Keys

Invite keys are an extension of the core protocol’s definition of OP_KEY_ADD to provide a standardized way for handling invitations for joining a group.

Specifically, invite keys are keys added using OP_CONTRACT or OP_KEY_ADD that:

  • Have a key name beginning with #inviteKey-
  • Have OP_KEY_REQUEST in their permissions
  • Have the following metadata in meta:
{
  "quantity": <positive-integer>,
  "creator": "<string>",
  "expires": <milliseconds-since-unix-epoch>,
  "private": {
    "keyId": "<keyId>",
    "content": "<encryptedKey>"
  }
}

These keys can then be shared using invite links. Protocol implementations will keep track of invite usage with each OP_KEY_REQUEST call that is sent, and ensure that invites can only be used if there are enough of them and they are not expired.

Note:

  • The private key for the invite key is included encrypted as part of meta.private, so that it can be decrypted by group members. It is encrypted using some other key that is known to group members.
  • The private key is included unencrypted in the invite link, so that it can be used immediately to send an OP_KEY_REQUEST by the recipient.
  • Invite key names begin with #inviteKey- so that you can define as many of them as you’d like by appending a unique suffix.