diff --git a/activitystreams/data.go b/activitystreams/data.go
index af5bedd..42f3bfc 100644
--- a/activitystreams/data.go
+++ b/activitystreams/data.go
@@ -13,6 +13,7 @@ type (
 		ID           string `json:"id"`
 		Owner        string `json:"owner"`
 		PublicKeyPEM string `json:"publicKeyPem"`
+		privateKey   []byte
 	}
 
 	Image struct {
diff --git a/activitystreams/person.go b/activitystreams/person.go
index 73f95d0..3fc4e41 100644
--- a/activitystreams/person.go
+++ b/activitystreams/person.go
@@ -41,3 +41,11 @@ func (p *Person) AddPubKey(k []byte) {
 		PublicKeyPEM: string(k),
 	}
 }
+
+func (p *Person) SetPrivKey(k []byte) {
+	p.PublicKey.privateKey = k
+}
+
+func (p *Person) GetPrivKey() []byte {
+	return p.PublicKey.privateKey
+}