diff --git a/src/mod.ts b/src/mod.ts
index 4fa528c..82acc9e 100644
--- a/src/mod.ts
+++ b/src/mod.ts
@@ -30,7 +30,10 @@ export async function main ([
         throw new Error('invalid salt, at least 5 characters long');
     }
 
-    const entropy = await PBKDF2(encode(salt), encode(passphrase));
+    const entropy = await PBKDF2({
+        salt: encode(salt),
+        passphrase: encode(passphrase),
+    });
 
     return ssh(new Uint8Array(entropy));
 
diff --git a/src/pbkdf2.ts b/src/pbkdf2.ts
index e98285f..7de2d78 100644
--- a/src/pbkdf2.ts
+++ b/src/pbkdf2.ts
@@ -4,12 +4,14 @@ import { webcrypto } from './utils.ts';
 
 
 
-export async function PBKDF2 (
+export async function PBKDF2 (opts: {
 
         salt: BufferSource,
         passphrase: BufferSource,
 
-): Promise<ArrayBuffer> {
+}): Promise<ArrayBuffer> {
+
+    const { salt, passphrase } = opts;
 
     const name = 'PBKDF2';
     const byte = 32;