Add auth utils for generating/hashing/encoding/decoding tokens

src/utils/auth.bench.ts

@@ -0,0 +1,11 @@
+import { generateToken, getTokenHash } from '@/utils/auth.ts';
+
+Deno.bench('generateToken', async () => {
+  await generateToken();
+});
+
+Deno.bench('getTokenHash', async (b) => {
+  const { token } = await generateToken();
+  b.start();
+  await getTokenHash(token);
+});

src/utils/auth.test.ts

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+import { assertEquals } from '@std/assert';
+import { decodeHex } from '@std/encoding/hex';
+
+import { generateToken, getTokenHash } from '@/utils/auth.ts';
+
+Deno.test('generateToken', async () => {
+  const sk = decodeHex('a0968751df8fd42f362213f08751911672f2a037113b392403bbb7dd31b71c95');
+
+  const { token, hash } = await generateToken(sk);
+
+  assertEquals(token, 'token15ztgw5wl3l2z7d3zz0cgw5v3zee09gphzyanjfqrhwma6vdhrj2sauwknd');
+  assertEquals(hash, decodeHex('ab4c4ead4d1c72a38fffd45b999937b7e3f25f867b19aaf252df858e77b66a8a'));
+});
+
+Deno.test('getTokenHash', async () => {
+  const hash = await getTokenHash('token15ztgw5wl3l2z7d3zz0cgw5v3zee09gphzyanjfqrhwma6vdhrj2sauwknd');
+  assertEquals(hash, decodeHex('ab4c4ead4d1c72a38fffd45b999937b7e3f25f867b19aaf252df858e77b66a8a'));
+});

src/utils/auth.ts

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+import { bech32 } from '@scure/base';
+import { generateSecretKey } from 'nostr-tools';
+
+/**
+ * Generate an auth token for the API.
+ *
+ * Returns a bech32 encoded API token and the SHA-256 hash of the bytes.
+ * The token should be presented to the user, but only the hash should be stored in the database.
+ */
+export async function generateToken(sk = generateSecretKey()): Promise<{ token: `token1${string}`; hash: Uint8Array }> {
+  const words = bech32.toWords(sk);
+  const token = bech32.encode('token', words);
+
+  const buffer = await crypto.subtle.digest('SHA-256', sk);
+  const hash = new Uint8Array(buffer);
+
+  return { token, hash };
+}
+
+/**
+ * Get the SHA-256 hash of an API token.
+ * First decodes from bech32 then hashes the bytes.
+ * Used to identify the user in the database by the hash of their token.
+ */
+export async function getTokenHash(token: `token1${string}`): Promise<Uint8Array> {
+  const { bytes: sk } = bech32.decodeToBytes(token);
+  const buffer = await crypto.subtle.digest('SHA-256', sk);
+
+  return new Uint8Array(buffer);
+}