Send hotlink access token hash on upload; keep secret client-side only.

frontend/src/utils/crypto/hashHotlinkAccessToken.ts

@@ -0,0 +1,9 @@
+export const hashHotlinkAccessToken = async (accessToken: string): Promise<string> => {
+    const encoder = new TextEncoder();
+
+    const data = encoder.encode(accessToken);
+
+    const digest = await crypto.subtle.digest('SHA-256', data);
+
+    return [...new Uint8Array(digest)].map(byte => byte.toString(16).padStart(2, '0')).join('');
+};