diff --git a/Sources/ClaimSet.swift b/Sources/ClaimSet.swift
index 2be08ca..7626498 100644
--- a/Sources/ClaimSet.swift
+++ b/Sources/ClaimSet.swift
@@ -1,3 +1,5 @@
+import Foundation
+
 public struct ClaimSet {
   var claims: [String: Any]
 
diff --git a/Sources/Encode.swift b/Sources/Encode.swift
index 04f4109..a864d4c 100644
--- a/Sources/Encode.swift
+++ b/Sources/Encode.swift
@@ -1,3 +1,5 @@
+import Foundation
+
 /*** Encode a set of claims
  - parameter claims: The set of claims
  - parameter algorithm: The algorithm to sign the payload with