From b0e34f3716feee0a73919a123033bad6b651ee52 Mon Sep 17 00:00:00 2001
From: Pascal Perrenoud <pascal@pband.ch>
Date: Wed, 15 May 2024 12:12:33 +0200
Subject: [PATCH] Implement PBKDF Closes #12

---
 index.ts           |  1 +
 src/pbkdf.ts       | 22 ++++++++++++++++++++++
 test/pbkdf.test.ts | 18 ++++++++++++++++++
 3 files changed, 41 insertions(+)
 create mode 100644 src/pbkdf.ts
 create mode 100644 test/pbkdf.test.ts

diff --git a/index.ts b/index.ts
index 617689f..35fb776 100644
--- a/index.ts
+++ b/index.ts
@@ -1,3 +1,4 @@
 export * as signature from 'signature'
 export * as boxes from 'boxes'
 export * as JWT from 'jwt'
+export {pbkdf} from './src/pbkdf'
diff --git a/src/pbkdf.ts b/src/pbkdf.ts
new file mode 100644
index 0000000..2fdfc53
--- /dev/null
+++ b/src/pbkdf.ts
@@ -0,0 +1,22 @@
+export async function pbkdf(password: string, salt: Uint8Array, usages: KeyUsage[]): Promise<CryptoKey> {
+    const keyMaterial = await window.crypto.subtle.importKey(
+        "raw",
+        new TextEncoder().encode(password),
+        "PBKDF2",
+        false,
+        ["deriveBits", "deriveKey"],
+    )
+
+    return crypto.subtle.deriveKey(
+        {
+            name: "PBKDF2",
+            iterations: 250_000,
+            hash: "SHA-512",
+            salt,
+        },
+        keyMaterial,
+        {name: "AES-GCM", length: 256},
+        false,
+        usages,
+    )
+}
diff --git a/test/pbkdf.test.ts b/test/pbkdf.test.ts
new file mode 100644
index 0000000..9a076e1
--- /dev/null
+++ b/test/pbkdf.test.ts
@@ -0,0 +1,18 @@
+import {expect, test} from 'bun:test'
+
+import {pbkdf} from 'pbkdf'
+
+test('Fields are set correctly', async () => {
+    const pwd = 'password'
+    const salt = new TextEncoder().encode('salt')
+    const usages = ['unwrapKey', 'encrypt']
+
+    const k1 = await pbkdf(pwd, salt, usages)
+    expect(k1.extractable).toBeFalse()
+    expect(k1.type).toBe('secret')
+
+    expect(k1.usages.length).toBe(usages.length)
+    for (const usage of usages) {
+        expect(k1.usages).toContain(usage)
+    }
+})