diff --git a/types/crypto-js/index.d.ts b/types/crypto-js/index.d.ts
index c3dad4637b..c066204df2 100644
--- a/types/crypto-js/index.d.ts
+++ b/types/crypto-js/index.d.ts
@@ -8,7 +8,7 @@ export as namespace CryptoJS;
 
 declare var CryptoJS: CryptoJS.Hashes;
 declare namespace CryptoJS {
-	type Hash = (message: string | LibWordArray, key?: string, ...options: any[]) => WordArray;
+	type Hash = (message: string | LibWordArray, key?: string | WordArray, ...options: any[]) => WordArray;
 	interface Cipher {
 		encrypt(message: string, secretPassphrase: string | WordArray, option?: CipherOption): WordArray;
 		decrypt(encryptedMessage: string | WordArray, secretPassphrase: string | WordArray, option?: CipherOption): DecryptedMessage;