diff --git a/spec.yaml b/spec.yaml
index 4abe5622..f894aa5f 100644
--- a/spec.yaml
+++ b/spec.yaml
@@ -640,6 +640,27 @@ definitions:
             type: string
             description: Name of the user accepting the invite.
             example: Richard Feynman
+          publicKey:
+            type: object
+            description: Public key of the user accepting the invite.
+            properties:
+              keyID:
+                type: string
+                format: url
+                description: Unique ID, formatted as a URL. the hostname is used to retrieve the public key via custom discovery
+                example: "https://my-gpg-keystore.com/key-id"
+              publicKeyPem:
+                type: string
+                example: |
+                  -----BEGIN PUBLIC KEY-----
+                  MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAryQICCl6NZ5gDKrnSztO
+                  3Hy8PEUcuyvg/ikC+VcIo2SFFSf18a3IMYldIugqqqZCs4/4uVW3sbdLs/6PfgdX
+                  7O9D22ZiFWHPYA2k2N744MNiCD1UE+tJyllUhSblK48bn+v1oZHCM0nYQ2NqUkvS
+                  j+hwUU3RiWl7x3D2s9wSdNt7XUtW05a/FXehsPSiJfKvHJJnGOX0BgTvkLnkAOTd
+                  OrUZ/wK69Dzu4IvrN4vs9Nes8vbwPa/ddZEzGR0cQMt0JBkhk9kU/qwqUseP1QRJ
+                  5I1jR4g8aYPL/ke9K35PxZWuDp3U0UPAZ3PjFAh+5T+fc7gzCs9dPzSHloruU+gl
+                  FQIDAQAB
+                  -----END PUBLIC KEY-----
   AcceptedInviteResponse:
     type: object
     allOf:
@@ -656,3 +677,24 @@ definitions:
             type: string
             description: Name of the user that sent the invite.
             example: John Doe
+          publicKey:
+            type: object
+            description: Public key of the user that sent the invite.
+            properties:
+              keyID:
+                type: string
+                format: url
+                description: Unique ID, formatted as an URL. the hostname is used to retrieve the public key via custom discovery
+                example: "https://my-gpg-keystore.com/key-id"
+              publicKeyPem:
+                type: string
+                example: |
+                  -----BEGIN PUBLIC KEY-----
+                  MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAryQICCl6NZ5gDKrnSztO
+                  3Hy8PEUcuyvg/ikC+VcIo2SFFSf18a3IMYldIugqqqZCs4/4uVW3sbdLs/6PfgdX
+                  7O9D22ZiFWHPYA2k2N744MNiCD1UE+tJyllUhSblK48bn+v1oZHCM0nYQ2NqUkvS
+                  j+hwUU3RiWl7x3D2s9wSdNt7XUtW05a/FXehsPSiJfKvHJJnGOX0BgTvkLnkAOTd
+                  OrUZ/wK69Dzu4IvrN4vs9Nes8vbwPa/ddZEzGR0cQMt0JBkhk9kU/qwqUseP1QRJ
+                  5I1jR4g8aYPL/ke9K35PxZWuDp3U0UPAZ3PjFAh+5T+fc7gzCs9dPzSHloruU+gl
+                  FQIDAQAB
+                  -----END PUBLIC KEY-----