feat: browser UI – unlock, table view, create/edit/delete with client-side crypto

Vanilla HTML/CSS/JS frontend served by Flask:
- Unlock screen: passphrase -> Argon2id session key, held in memory
  only (never sent to the server); "Sperren" wipes key and DOM rows.
- Records table (Person A/B, start/end, action) rendered via
  textContent only (no HTML injection); undecryptable rows are flagged.
- Create/edit modal encrypts payloads with XChaCha20-Poly1305 before
  any network call; updates carry the server version (optimistic lock,
  conflict toast on 409); delete fetches current version first.

🤖 Generated with Codebuff
Co-Authored-By: Codebuff <noreply@codebuff.com>

backend/static/index.html

@@ -0,0 +1,84 @@
+<!DOCTYPE html>
+<html lang="de">
+<head>
+  <meta charset="utf-8" />
+  <meta name="viewport" content="width=device-width, initial-scale=1" />
+  <title>crushdb</title>
+  <link rel="stylesheet" href="/static/style.css" />
+</head>
+<body>
+  <h1>crushdb</h1>
+  <p class="tagline">Verschlüsselte Datensätze zwischen zwei Personen</p>
+
+  <section id="flash" class="flash" aria-live="polite"></section>
+
+  <!-- unlock screen: passphrase stays in memory only -->
+  <section id="unlock">
+    <form id="unlock-form" autocomplete="off">
+      <label for="passphrase">Passphrase</label>
+      <input
+        type="password"
+        id="passphrase"
+        autocomplete="off"
+        required
+        placeholder="Passphrase eingeben …"
+      />
+      <button type="submit">Entsperren</button>
+      <p class="hint">
+        Die Passphrase verlässt niemals deinen Browser. Sie wird per
+        Argon2id lokal abgeleitet und nur im Arbeitsspeicher gehalten.
+      </p>
+    </form>
+  </section>
+
+  <!-- main app, hidden until unlocked -->
+  <section id="app" hidden>
+    <div class="toolbar">
+      <button id="new-btn" type="button">+ Neuer Datensatz</button>
+      <button id="lock-btn" type="button">Sperren</button>
+    </div>
+
+    <table id="records">
+      <thead>
+        <tr>
+          <th>Person A</th>
+          <th>Person B</th>
+          <th>Start</th>
+          <th>Ende</th>
+          <th>Aktion</th>
+          <th></th>
+        </tr>
+      </thead>
+      <tbody></tbody>
+    </table>
+  </section>
+
+  <!-- create/edit modal -->
+  <div id="editor-backdrop" hidden>
+    <form id="editor" autocomplete="off">
+      <h2 id="editor-title">Neuer Datensatz</h2>
+      <label>Person A
+        <input id="f-persona" type="text" required maxlength="120" />
+      </label>
+      <label>Person B
+        <input id="f-personb" type="text" required maxlength="120" />
+      </label>
+      <label>Start (optional)
+        <input id="f-tsstart" type="datetime-local" />
+      </label>
+      <label>Ende (optional)
+        <input id="f-tsend" type="datetime-local" />
+      </label>
+      <label>Aktion
+        <input id="f-action" type="text" required maxlength="500" />
+      </label>
+      <div class="actions">
+        <button type="submit">Speichern</button>
+        <button type="button" id="editor-cancel">Abbrechen</button>
+      </div>
+    </form>
+  </div>
+
+  <script type="module" src="/static/ui.js"></script>
+</body>
+</html>

backend/static/style.css

@@ -0,0 +1,129 @@
+/* crushdb – simple, clean dark UI */
+
+:root {
+  --bg: #101418;
+  --panel: #1a2028;
+  --panel-2: #202830;
+  --border: #2c3642;
+  --text: #e6edf3;
+  --muted: #8b98a5;
+  --accent: #4da3ff;
+  --danger: #ff5d5d;
+  --ok: #47d68a;
+}
+
+* { box-sizing: border-box; }
+
+body {
+  margin: 0 auto;
+  max-width: 960px;
+  padding: 2rem 1rem;
+  font-family: system-ui, -apple-system, "Segoe UI", sans-serif;
+  background: var(--bg);
+  color: var(--text);
+  line-height: 1.5;
+}
+
+h1 { margin: 0 0 0.25rem; font-size: 1.6rem; }
+.tagline { margin: 0 0 1.5rem; color: var(--muted); }
+
+#flash {
+  min-height: 1.4rem;
+  margin-bottom: 1rem;
+  color: var(--ok);
+}
+#flash.error { color: var(--danger); }
+
+#unlock {
+  max-width: 420px;
+  margin: 3rem auto;
+  background: var(--panel);
+  border: 1px solid var(--border);
+  border-radius: 10px;
+  padding: 1.5rem;
+}
+
+#unlock label { display: block; margin-bottom: 0.5rem; }
+#unlock input {
+  width: 100%;
+  margin-bottom: 1rem;
+}
+.hint { color: var(--muted); font-size: 0.85rem; margin-top: 1rem; }
+
+input, button {
+  font: inherit;
+  color: var(--text);
+}
+
+input {
+  background: var(--panel-2);
+  border: 1px solid var(--border);
+  border-radius: 6px;
+  padding: 0.5rem 0.7rem;
+}
+input:focus { outline: 1px solid var(--accent); }
+
+button {
+  background: var(--accent);
+  color: #0b1016;
+  border: none;
+  border-radius: 6px;
+  padding: 0.5rem 1rem;
+  cursor: pointer;
+  font-weight: 600;
+}
+button:hover { filter: brightness(1.1); }
+
+#app .toolbar {
+  display: flex;
+  gap: 0.75rem;
+  margin-bottom: 1rem;
+}
+#lock-btn { background: var(--panel-2); color: var(--text); border: 1px solid var(--border); }
+
+table {
+  width: 100%;
+  border-collapse: collapse;
+  background: var(--panel);
+  border: 1px solid var(--border);
+  border-radius: 10px;
+  overflow: hidden;
+}
+
+th, td {
+  padding: 0.6rem 0.75rem;
+  text-align: left;
+  border-bottom: 1px solid var(--border);
+}
+thead th { background: var(--panel-2); color: var(--muted); font-weight: 600; }
+tbody tr:last-child td { border-bottom: none; }
+tbody tr:hover { background: var(--panel-2); }
+
+.row-error td { color: var(--danger); font-size: 0.9rem; }
+
+td:last-child, td button { white-space: nowrap; }
+td button + button { margin-left: 0.4rem; }
+
+/* modal */
+#editor-backdrop {
+  position: fixed;
+  inset: 0;
+  background: rgba(0, 0, 0, 0.6);
+  display: flex;
+  align-items: center;
+  justify-content: center;
+}
+
+#editor {
+  background: var(--panel);
+  border: 1px solid var(--border);
+  border-radius: 10px;
+  padding: 1.5rem;
+  width: min(440px, 92vw);
+}
+
+#editor h2 { margin-top: 0; font-size: 1.15rem; }
+#editor label { display: block; margin-bottom: 0.75rem; color: var(--muted); }
+#editor input { width: 100%; margin-top: 0.25rem; }
+#editor .actions { display: flex; gap: 0.75rem; margin-top: 1rem; }
+#editor-cancel { background: var(--panel-2); color: var(--text); border: 1px solid var(--border); }

backend/static/ui.js

@@ -0,0 +1,275 @@
+/**
+ * ui.js – browser UI logic for crushdb.
+ *
+ * Flow:
+ *  1. User enters a passphrase → Argon2id derives the session key in
+ *     memory (never sent anywhere, never persisted).
+ *  2. Fetch ciphertext records from /api/records, decrypt each in
+ *     memory; decrypt failures are surfaced as "wrong passphrase or
+ *     tampered record" without leaking details.
+ *  3. Create/edit records: form values are encrypted client-side
+ *     before POST/PUT; the server only ever sees ciphertext.
+ *  4. Delete requires the record's current version (optimistic lock).
+ *  5. "Lock" wipes the passphrase field and releases decrypted rows so
+ *     nothing sensitive lingers in the DOM.
+ */
+
+import {
+  deriveKey,
+  encryptRecord,
+  decryptRecord,
+  randomSalt,
+  randomUuid,
+  wipeKey,
+} from "./crypto.js";
+
+// ---------- tiny DOM helpers ----------
+
+const $ = (sel) => document.querySelector(sel);
+
+function el(tag, attrs = {}, children = []) {
+  const node = document.createElement(tag);
+  for (const [k, v] of Object.entries(attrs)) {
+    if (k === "class") node.className = v;
+    else if (k === "text") node.textContent = v;
+    else node.setAttribute(k, v);
+  }
+  for (const child of children) node.appendChild(child);
+  return node;
+}
+
+function flash(msg, isError = false) {
+  const box = $("#flash");
+  box.textContent = msg;
+  box.className = isError ? "flash error" : "flash";
+  setTimeout(() => { box.textContent = ""; }, 4000);
+}
+
+// ---------- session state (memory only) ----------
+
+let sessionKey = null; // Uint8Array(32) or null
+
+function resetSession() {
+  wipeKey(sessionKey);
+  sessionKey = null;
+  $("#records").replaceChildren();
+  $("#app").hidden = true;
+  $("#unlock").hidden = false;
+  $("#passphrase").value = "";
+  $("#passphrase").focus();
+}
+
+// ---------- API helpers ----------
+
+async function api(path, opts = {}) {
+  const res = await fetch(path, {
+    headers: opts.body ? { "Content-Type": "application/json" } : {},
+    ...opts,
+  });
+  if (!res.ok) {
+    let detail = "";
+    try { detail = (await res.json()).error ?? ""; } catch { /* noop */ }
+    throw new Error(`HTTP ${res.status}${detail ? ": " + detail : ""}`);
+  }
+  if (res.status === 204) return null;
+  return res.json();
+}
+
+// ---------- rendering ----------
+
+function iso(ts) {
+  if (ts === null || ts === "") return "–";
+  const d = new Date(ts);
+  return isNaN(d) ? String(ts) : d.toLocaleString();
+}
+
+function renderRow(record, payload) {
+  const tr = el("tr");
+  const cells = [
+    payload.personA,
+    payload.personB,
+    iso(payload.tsStart),
+    iso(payload.tsEnd),
+    payload.action,
+  ];
+  for (const text of cells) {
+    const td = el("td");
+    td.textContent = text ?? ""; // textContent = no HTML injection
+    tr.appendChild(td);
+  }
+
+  const ops = el("td");
+  ops.appendChild(
+    el("button", {
+      text: "Bearbeiten",
+      type: "button",
+      onclick: () => openEditor(record, payload),
+    })
+  );
+  ops.appendChild(
+    el("button", {
+      text: "Löschen",
+      type: "button",
+      onclick: () => removeRecord(record),
+    })
+  );
+  tr.appendChild(ops);
+  return tr;
+}
+
+async function reload() {
+  const tbody = $("#records tbody");
+  tbody.replaceChildren();
+  const raw = await api("/api/records");
+  let failures = 0;
+  for (const record of raw) {
+    try {
+      const payload = decryptRecord(sessionKey, record);
+      payload.__version = record.version; // used for optimistic locking
+      tbody.appendChild(renderRow(record, payload));
+    } catch {
+      failures++;
+      tbody.appendChild(
+        el("tr", { class: "row-error" }, [
+          el("td", { colspan: "6", text: "Datensatz nicht entschlüsselbar (falsche Passphrase oder manipuliert)." }),
+        ])
+      );
+    }
+  }
+  if (failures > 0) flash(`${failures} Datensatz/Datensätze konnten nicht entschlüsselt werden.`, true);
+}
+
+function openEditor(record, payload) {
+  const form = $("#editor");
+  form.dataset.uuid = record.uuid;
+  form.dataset.version = payload.__version;
+  form.dataset.salt = record.salt;
+  $("#editor-title").textContent = "Datensatz bearbeiten";
+  $("#f-persona").value = payload.personA ?? "";
+  $("#f-personb").value = payload.personB ?? "";
+  $("#f-tsstart").value = payload.tsStart ? new Date(payload.tsStart).toISOString().slice(0, 16) : "";
+  $("#f-tsend").value = payload.tsEnd ? new Date(payload.tsEnd).toISOString().slice(0, 16) : "";
+  $("#f-action").value = payload.action ?? "";
+  $("#editor-backdrop").hidden = false;
+}
+
+function newRecord() {
+  const form = $("#editor");
+  form.reset();
+  form.dataset.uuid = randomUuid();
+  form.dataset.version = "";
+  form.dataset.salt = "";
+  $("#editor-title").textContent = "Neuer Datensatz";
+  $("#editor-backdrop").hidden = false;
+}
+
+function closeEditor() {
+  $("#editor-backdrop").hidden = true;
+  $("#editor").reset();
+}
+
+function tsOrNull(inputValue) {
+  if (!inputValue) return null;
+  const d = new Date(inputValue);
+  return isNaN(d) ? null : d.toISOString();
+}
+
+// ---------- record operations ----------
+
+async function saveRecord(ev) {
+  ev.preventDefault();
+  if (!sessionKey) { flash("Bitte zuerst entsperren.", true); return; }
+
+  const form = $("#editor");
+  const payload = {
+    personA: $("#f-persona").value.trim(),
+    personB: $("#f-personb").value.trim(),
+    tsStart: tsOrNull($("#f-tsstart").value),
+    tsEnd: tsOrNull($("#f-tsend").value),
+    action: $("#f-action").value.trim(),
+  };
+  if (!payload.personA || !payload.personB || !payload.action) {
+    flash("Person A, Person B und Aktion sind erforderlich.", true);
+    return;
+  }
+
+  const isEdit = form.dataset.version !== "";
+  const salt = isEdit ? new Uint8Array(atob(form.dataset.salt).split("").map((c) => c.charCodeAt(0))) : randomSalt();
+  const enc = encryptRecord(sessionKey, form.dataset.uuid, payload, salt);
+
+  try {
+    if (isEdit) {
+      enc.version = Number(form.dataset.version);
+      await api(`/api/records/${encodeURIComponent(enc.uuid)}`, { method: "PUT", body: JSON.stringify(enc) });
+    } else {
+      await api("/api/records", { method: "POST", body: JSON.stringify(enc) });
+    }
+    closeEditor();
+    await reload();
+    flash(isEdit ? "Datensatz aktualisiert." : "Datensatz erstellt.");
+  } catch (e) {
+    closeEditor();
+    if (String(e).includes("409")) {
+      flash("Konflikt: Der Datensatz wurde zwischenzeitlich geändert. Liste wird neu geladen.", true);
+    } else {
+      flash("Speichern fehlgeschlagen: " + e.message, true);
+    }
+    await reload();
+  }
+}
+
+async function removeRecord(record) {
+  if (!sessionKey) { flash("Bitte zuerst entsperren.", true); return; }
+  if (!confirm("Diesen Datensatz wirklich löschen?")) return;
+  try {
+    const current = await api(`/api/records/${encodeURIComponent(record.uuid)}`);
+    await api(`/api/records/${encodeURIComponent(record.uuid)}`, {
+      method: "DELETE",
+      body: JSON.stringify({ version: current.version }),
+    });
+    await reload();
+    flash("Datensatz gelöscht.");
+  } catch (e) {
+    if (String(e).includes("409")) flash("Konflikt beim Löschen (Version geändert). Bitte erneut versuchen.", true);
+    else flash("Löschen fehlgeschlagen: " + e.message, true);
+    await reload();
+  }
+}
+
+// ---------- unlock / lock ----------
+
+async function unlock(ev) {
+  ev.preventDefault();
+  const passphrase = $("#passphrase").value;
+  if (!passphrase) { flash("Bitte Passphrase eingeben.", true); return; }
+  // Salt for key derivation: per-record salts are used for the AEAD;
+  // for the session key we use a fixed domain-salt so all records can
+  // be opened with one passphrase. It contains no secret.
+  const domainSalt = new TextEncoder().encode("crushdb://session-key-v1");
+  try {
+    sessionKey = deriveKey(passphrase, domainSalt);
+    $("#passphrase").value = "";
+    $("#unlock").hidden = true;
+    $("#app").hidden = false;
+    await reload();
+  } catch (e) {
+    flash("Entsperren fehlgeschlagen: " + e.message, true);
+  }
+}
+
+function lock() {
+  if (!confirm("Sperren? Alle entschlüsselten Daten werden verworfen.")) return;
+  resetSession();
+}
+
+// ---------- wire-up ----------
+
+document.addEventListener("DOMContentLoaded", () => {
+  $("#unlock-form").addEventListener("submit", unlock);
+  $("#lock-btn").addEventListener("click", lock);
+  $("#new-btn").addEventListener("click", newRecord);
+  $("#editor").addEventListener("submit", saveRecord);
+  $("#editor-cancel").addEventListener("click", closeEditor);
+  window.addEventListener("beforeunload", () => wipeKey(sessionKey));
+  $("#passphrase").focus();
+});