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+<!doctype html>
+<html><head><meta charset="utf-8">
+<title>webapp cookie rotation: who holds what</title>
+<!-- drawn after the style of MarkM's ERTP slides; cookie-rotation-wiring.png is a headless-Chromium screenshot of this page -->
+<style>
+  html, body { margin: 0; background: #fff; }
+  .sans { font-family: "Helvetica Neue", "DejaVu Sans", sans-serif; }
+  .obj { font-family: "DejaVu Serif", serif; font-style: italic; }
+  .mono { font-family: "DejaVu Sans Mono", monospace; }
+</style></head>
+<body>
+<svg id="c" xmlns="http://www.w3.org/2000/svg" width="1120" height="820" viewBox="0 0 1120 820">
+  <defs>
+    <radialGradient id="ball" cx="40%" cy="35%" r="70%">
+      <stop offset="0%" stop-color="#7cc8f8"/>
+      <stop offset="100%" stop-color="#3aa6ee"/>
+    </radialGradient>
+    <linearGradient id="objfill" x1="0" y1="0" x2="0" y2="1">
+      <stop offset="0%" stop-color="#6cbcf4"/>
+      <stop offset="100%" stop-color="#4aa8ec"/>
+    </linearGradient>
+    <marker id="head" viewBox="0 0 10 10" refX="9" refY="5" markerWidth="9" markerHeight="9" orient="auto-start-reverse">
+      <path d="M0,0 L10,5 L0,10 z" fill="#1d4f7a"/>
+    </marker>
+  </defs>
+</svg>
+<script>
+const svg = document.getElementById("c");
+const NS = "http://www.w3.org/2000/svg";
+const el = (name, attrs, parent = svg) => {
+  const e = document.createElementNS(NS, name);
+  for (const [k, v] of Object.entries(attrs)) e.setAttribute(k, v);
+  parent.appendChild(e);
+  return e;
+};
+const text = (x, y, s, cls, attrs = {}) => {
+  const t = el("text", { x, y, class: cls, "text-anchor": "middle", fill: "#1d3550", ...attrs });
+  t.textContent = s;
+  return t;
+};
+
+const INK = "#1d4f7a";
+const dot = (x, y) => el("circle", { cx: x, cy: y, r: 4.5, fill: INK });
+/** a reference: dot at the holder, arrowhead at the target */
+const ref = (x1, y1, x2, y2, bend = 0, extra = {}) => {
+  dot(x1, y1);
+  const mx = (x1 + x2) / 2 - (y2 - y1) * bend, my = (y1 + y2) / 2 + (x2 - x1) * bend;
+  el("path", { d: `M${x1},${y1} Q${mx},${my} ${x2},${y2}`, fill: "none", stroke: INK, "stroke-width": 2, "marker-end": "url(#head)", ...extra });
+};
+
+// maker box: a pale rounded region, with stacked instances inside
+function maker(x, y, w, h, label) {
+  el("rect", { x, y, width: w, height: h, rx: 26, fill: "#d6ecfb", stroke: "#b5dbf5", "stroke-width": 1.5 });
+  text(x + 18, y + 30, label, "obj", { "text-anchor": "start", "font-size": 20 });
+  for (let i = 2; i >= 0; i -= 1) {
+    el("rect", {
+      x: x + 18 + i * 9, y: y + 48 + i * 9, width: w - 52, height: h - 82, rx: 22,
+      fill: "#c8e5fa", stroke: "#8ec9f2", "stroke-width": 1.5, "fill-opacity": 0.9,
+    });
+  }
+}
+// an object: rounded square, optionally stacked (several made)
+function obj(x, y, w, h, label, stacked = false) {
+  const n = stacked ? 3 : 1;
+  for (let i = n - 1; i >= 0; i -= 1) {
+    el("rect", { x: x + i * 7, y: y - i * 7, width: w, height: h, rx: 12, fill: "url(#objfill)", stroke: "#2f8fd6", "stroke-width": 1.5 });
+  }
+  text(x + w / 2, y + h / 2 + 7, label, "obj", { "font-size": 19 });
+}
+function actor(cx, cy, label) {
+  el("circle", { cx, cy, r: 52, fill: "url(#ball)", stroke: "#2f8fd6", "stroke-width": 1.5 });
+  text(cx, cy + 6, label, "sans", { "font-size": label.length > 8 ? 15 : 17 });
+}
+// a table like the ERTP ledger
+function table(x, y, title, rows, colW) {
+  const rowH = 28, w = colW[0] + colW[1];
+  el("rect", { x, y, width: w, height: 36 + rowH * rows.length, fill: "#5fb5f2", stroke: "#2f8fd6", "stroke-width": 1.5 });
+  text(x + w / 2, y + 25, title, "obj", { "font-size": 18 });
+  rows.forEach(([k, v], i) => {
+    const ry = y + 36 + i * rowH;
+    el("line", { x1: x, y1: ry, x2: x + w, y2: ry, stroke: "#2f8fd6", "stroke-width": 1.2 });
+    text(x + 10, ry + 19, k, "mono", { "text-anchor": "start", "font-size": 14 });
+    if (v) text(x + colW[0] + 10, ry + 19, v, "mono", { "text-anchor": "start", "font-size": 14 });
+  });
+  el("line", { x1: x + colW[0], y1: y + 36, x2: x + colW[0], y2: y + 36 + rowH * rows.length, stroke: "#1d4f7a", "stroke-width": 1.5 });
+  return { rowY: (i) => y + 36 + i * rowH + rowH / 2, x, w, colX: x + colW[0] };
+}
+
+// speech bubble (Alice rotates after logging in again)
+el("path", {
+  d: "M30,22 h470 a16,16 0 0 1 16,16 v34 a16,16 0 0 1 -16,16 h-330 l-38,48 l6,-48 h-102 a16,16 0 0 1 -16,-16 v-34 a16,16 0 0 1 16,-16 z",
+  fill: "#d9d9d9", stroke: "#555", "stroke-width": 2,
+});
+const code = el("text", { x: 46, y: 62, class: "mono", "font-size": 17, fill: "#222" });
+code.innerHTML = '<tspan fill="#b0177b">await</tspan> E(store).set(<tspan fill="#1a7f37">"cookie"</tspan>, freshCookie);';
+
+// actors
+actor(150, 200, "Alice");
+actor(560, 200, "diigo-cache");
+actor(930, 200, "Mallory");
+
+// makers
+maker(30, 320, 470, 470, "makeMapStore");
+maker(560, 320, 530, 470, "makeWebApp");
+
+// MapStoreDo insides
+obj(80, 420, 120, 80, "store");
+obj(80, 600, 120, 80, "readOnly", true);
+const kv = table(260, 430, "kv", [["cookie", "session=…"], ["", ""], ["", ""], ["", ""], ["", ""]], [90, 110]);
+
+// WebAppDo insides
+obj(620, 560, 140, 90, "access", true);
+const init = table(830, 420, "init", [["url", "diigo…"], ["headers", "{…}"], ["headerStore", ""], ["", ""]], [130, 85]);
+
+// references
+ref(140, 228, 125, 418, 0.05); // Alice → store
+ref(172, 224, 508, 210, 0.04); // Alice → diigo-cache (she wired it)
+ref(560 - 6, 200 + 18, 660, 553, 0.12); // cache → access
+ref(930 - 14, 200 + 20, 720, 553, -0.08); // Mallory → access
+ref(160, 470, kv.x - 2, kv.rowY(0), 0.05); // store → kv
+ref(150, 666, kv.x - 2, kv.rowY(0) + 6, -0.25); // readOnly → kv (read)
+ref(760, 600, init.x - 2, init.rowY(2), -0.1); // access → init
+ref(init.colX + 40, init.rowY(2), 208, 640, -0.28); // headerStore → readOnly
+
+// captions
+const cap = (x, y, s, attrs = {}) => text(x, y, s, "sans", { "font-size": 14, fill: "#33536f", ...attrs });
+cap(930, 118, "holds the instance id:", {});
+cap(930, 136, "uses the cookie, can't reach store", {});
+cap(330, 300, "storeId: rotate · revoke", {});
+cap(760, 806, "init.headerStore → the store's read-only facet, read at every send", {});
+cap(265, 806, "shapes: keyShape \"cookie\", valueShape M.string()", {});
+</script>
+</body></html>