diff --git a/Sources/Keycard/Crypto.swift b/Sources/Keycard/Crypto.swift
index b3021dd..7c467a3 100644
--- a/Sources/Keycard/Crypto.swift
+++ b/Sources/Keycard/Crypto.swift
@@ -1,6 +1,7 @@
 import secp256k1
 import CryptoSwift
 import CommonCrypto
+import Foundation
 
 enum PBKDF2HMac {
     case sha256