diff --git a/src/resolver.ts b/src/resolver.ts
index e237930..aa87638 100644
--- a/src/resolver.ts
+++ b/src/resolver.ts
@@ -16,13 +16,13 @@ export interface DIDDocument {
   '@context': 'https://w3id.org/did/v1'
   id: string
   publicKey: PublicKey[]
-  authentication?: Authentication[]
+  authentication?: (string | PublicKey)[]
   uportProfile?: any
   service?: ServiceEndpoint[]
   created?: string
   updated?: string
   proof?: LinkedDataProof
-  keyAgreement?: (string|PublicKey)[]
+  keyAgreement?: (string | PublicKey)[]
 }
 
 export interface ServiceEndpoint {
@@ -43,11 +43,6 @@ export interface PublicKey {
   publicKeyPem?: string
 }
 
-export interface Authentication {
-  type: string
-  publicKey: string
-}
-
 export interface LinkedDataProof {
   type: string
   created: string