diff --git a/packages/wasm-crypto/README.md b/packages/wasm-crypto/README.md
index eb70bca3..718f6e49 100644
--- a/packages/wasm-crypto/README.md
+++ b/packages/wasm-crypto/README.md
@@ -22,7 +22,7 @@ async function main () {
   const phrase = bip39Generate();
 
   // get ed25519 seed from phrase
-  const seed = bip39ToSeed(phrase);
+  const seed = bip39ToSeed(phrase, '');
 
   // display
   console.log('phrase:', phrase);