Replaced mock signal signatures with real SEP-53 Ed25519 proof-of-wallet-ownership: clients sign the payload via the wallet, the server verifies each signature with Keypair.verify and rejects invalid or forged ones, and the UI shows a verified badge based on a persisted signature_verified flag. Includes DB migration, unit tests, and doc updates.

PROJECT_ARCHITECTURE.md

@@ -122,6 +122,28 @@ Owns:
 - Testnet-only assumptions must be explicit in docs and code comments.
 - Any privileged operation must validate input shape and origin intent.
 
+## 9a) Signal & reply authorship proof (SEP-53)
+
+Community signals and replies now carry a Verifiable Ed25519 proof of wallet
+ownership instead of a mock signature:
+
+- **Client** (`components/signal-compose.tsx`, `app/signals/[id]/signal-detail-client.tsx`)
+  signs a canonical payload `{ title, body, timestamp }` via the selected
+  wallet's SEP-53 `signMessage` (`lib/viewer-signature.ts:signSignalPayload`).
+- **Server** (`app/api/signals/route.ts`, `app/api/signals/[id]/replies/route.ts`)
+  reconstructs the same payload and verifies it with
+  `Keypair.fromPublicKey(author).verify(prefix + message, signature)`
+  (`lib/viewer-signature.ts:verifySignalSignature`). Missing, malformed, or
+  forged signatures (signature claiming another wallet) are rejected with
+  `400`.
+- **Badge**: verified authorship is persisted as `signature_verified` on the
+  `signals` / `signal_replies` SQLite rows and surfaced in the UI, so verified
+  signals are visually distinguished from legacy posts.
+
+All signing stays client-side; the server never holds user keys. Signed string
+is a fixed-size digest of the canonical payload, keeping it under wallet
+`sign_message` size limits.
+
 ## 10) Feature flags (rolling delivery)
 
 | Flag | Env | Purpose | Default | Rollback |

app/api/signals/[id]/replies/route.ts

@@ -4,6 +4,7 @@ import { getSignal, createReply, AttributionInReplySchema, recordReplyAttributio
 import { createNotification } from "@/lib/notification-store"
 import { dispatchPushNotification, extractMentionedWallets, isPhase92Enabled } from "@/lib/push-notifications"
 import { createApiRequestContext } from "@/lib/api-observability"
+import { verifySignalSignature } from "@/lib/viewer-signature"
 import { isFeatureEnabled } from "@/lib/feature-flags"
 import { z } from "zod"
 
@@ -31,6 +32,7 @@ type ReplyBody = {
   body?: unknown
   wallet?: unknown
   signature?: unknown
+  timestamp?: unknown
   attribution?: unknown
   contributors?: unknown
 }
@@ -81,6 +83,25 @@ export async function POST(
       { status: 400, event: "signals.reply.validation_failed", metadata: { reason: "body_length" } },
     )
   }
+  if (typeof body.timestamp !== "number" || !Number.isFinite(body.timestamp)) {
+    return api.json(
+      { error: "Invalid signature timestamp" },
+      { status: 400, event: "signals.reply.validation_failed", metadata: { reason: "timestamp" } },
+    )
+  }
+
+  const walletStr = body.wallet
+  const signatureVerified = await verifySignalSignature(
+    walletStr,
+    { title: "", body: (body.body as string).trim(), timestamp: body.timestamp as number },
+    body.signature as string,
+  )
+  if (!signatureVerified) {
+    return api.json(
+      { error: "Invalid signature: reply not signed by this wallet" },
+      { status: 400, event: "signals.reply.invalid_signature" },
+    )
+  }
 
   // phase-156 (Module #56): reject posts from wallets on the governed deny-list.
   // No-op when the flag is off. Wrapped so a store read failure never 500s the
@@ -144,7 +165,6 @@ export async function POST(
       return api.json({ error: "Signal not found" }, { status: 404, event: "signals.reply.signal_missing", metadata: { signal_id: id } })
     }
 
-    const walletStr = body.wallet
     const res = await fetch(
       `${request.nextUrl.origin}/api/artist-profile?walletAddress=${encodeURIComponent(walletStr)}`,
       { headers: { "x-correlation-id": api.correlationId } },
@@ -167,6 +187,7 @@ export async function POST(
       body: (body.body as string).trim(),
       upvotes: [],
       signature: body.signature as string,
+      signature_verified: signatureVerified,
     })
 
     // phase-116: record contributor attribution (flag-gated, best-effort)

app/api/signals/route.ts

@@ -5,6 +5,7 @@ import {
   createSignal,
   getSignalChannelStats,
 } from "@/lib/signal-store"
+import { verifySignalSignature } from "@/lib/viewer-signature"
 import type { Signal } from "@/lib/signal-store"
 import { getAllWorldCollections } from "@/lib/narrative-world-store"
 import { checkAndUnlock } from "@/lib/achievement-store"
@@ -48,6 +49,7 @@ type CreateSignalBody = {
   channel?: unknown
   wallet?: unknown
   signature?: unknown
+  timestamp?: unknown
   nft_token_id?: unknown
   nft_collection_id?: unknown
   nft_name?: unknown
@@ -72,6 +74,9 @@ export async function POST(request: NextRequest) {
   if (typeof body.signature !== "string" || body.signature.length === 0) {
     return NextResponse.json({ error: "Signature required" }, { status: 400 })
   }
+  if (typeof body.timestamp !== "number" || !Number.isFinite(body.timestamp)) {
+    return NextResponse.json({ error: "Invalid signature timestamp" }, { status: 400 })
+  }
   if (typeof body.title !== "string" || body.title.trim().length === 0) {
     return NextResponse.json({ error: "Title required" }, { status: 400 })
   }
@@ -88,6 +93,24 @@ export async function POST(request: NextRequest) {
     return NextResponse.json({ error: "Channel required" }, { status: 400 })
   }
 
+  const walletStr = body.wallet
+  const proofPayload = {
+    title: body.title.trim(),
+    body: (body.body as string).trim(),
+    timestamp: body.timestamp as number,
+  }
+  const signatureVerified = await verifySignalSignature(
+    walletStr,
+    proofPayload,
+    body.signature as string,
+  )
+  if (!signatureVerified) {
+    return NextResponse.json(
+      { error: "Invalid signature: payload not signed by this wallet" },
+      { status: 400 },
+    )
+  }
+
   let poll: Signal["poll"]
   if (body.type === "poll") {
     if (!isFeatureEnabled("phase-90")) {
@@ -131,7 +154,6 @@ export async function POST(request: NextRequest) {
     }
   }
 
-  const walletStr = body.wallet
   const res = await fetch(
     `${request.nextUrl.origin}/api/artist-profile?walletAddress=${encodeURIComponent(walletStr)}`,
   ).catch(() => null)
@@ -151,6 +173,7 @@ export async function POST(request: NextRequest) {
     body: (body.body as string).trim(),
     upvotes: [],
     signature: body.signature as string,
+    signature_verified: signatureVerified,
     type: body.type === "poll" ? "poll" : "post",
     ...(poll ? { poll } : {}),
     ...(scheduledFor ? { scheduled_for: scheduledFor } : {}),

app/signals/[id]/page.tsx

@@ -105,9 +105,13 @@ export default async function SignalDetailPage({ params }: Props) {
             </span>
             <span
               className="font-mono text-[9px] px-1.5 py-0.5"
-              style={{ background: "#EEEDFE", color: "#534AB7" }}
+              style={
+                signal.signature_verified
+                  ? { background: "#E1F5EE", color: "#0F6E56" }
+                  : { background: "#EEEDFE", color: "#534AB7" }
+              }
             >
-              ✓ WALLET
+              {signal.signature_verified ? "✓ VERIFIED" : "✓ WALLET"}
             </span>
             <span className="font-mono text-[9px] text-muted-foreground/40 border border-[var(--color-border-tertiary)] px-1.5 py-0.5 uppercase tracking-widest">
               {signal.channel.toUpperCase()}

app/signals/[id]/signal-detail-client.tsx

@@ -4,6 +4,7 @@ import { useState } from "react"
 import { useWallet } from "@/components/wallet-provider"
 import { useLang } from "@/components/lang-context"
 import { WalletAvatar } from "@/components/wallet-avatar"
+import { signSignalPayload } from "@/lib/viewer-signature"
 import type { SignalReply } from "@/lib/signal-store"
 
 const copy = {
@@ -15,6 +16,8 @@ const copy = {
     ctaBusy: "[ SENDING… ]",
     noWallet: "[ CONNECT_WALLET_TO_REPLY ]",
     walletBadge: "✓ WALLET",
+    verifiedBadge: "✓ VERIFIED",
+    legacyBadge: "LEGACY",
   },
   es: {
     replies: "RESPUESTAS",
@@ -24,6 +27,8 @@ const copy = {
     ctaBusy: "[ ENVIANDO… ]",
     noWallet: "[ CONECTAR_WALLET_PARA_RESPONDER ]",
     walletBadge: "✓ WALLET",
+    verifiedBadge: "✓ VERIFICADO",
+    legacyBadge: "LEGADO",
   },
 }
 
@@ -60,14 +65,20 @@ export function SignalDetailClient({ signalId, initialReplies }: Props) {
     setError(null)
     setBusy(true)
     try {
+      const timestamp = Date.now()
+      const replyBodyTrimmed = replyBody.trim()
+      const signature = await signSignalPayload(
+        { title: "", body: replyBodyTrimmed, timestamp },
+        address,
+      )
       const res = await fetch(`/api/signals/${signalId}/replies`, {
         method: "POST",
         headers: { "Content-Type": "application/json" },
         body: JSON.stringify({
-          body: replyBody.trim(),
+          body: replyBodyTrimmed,
           wallet: address,
-          // TODO: replace provisional signature with Freighter signMessage when available
-          signature: address,
+          signature,
+          timestamp,
         }),
       })
       const data = (await res.json().catch(() => ({}))) as { reply?: SignalReply; error?: string }
@@ -113,9 +124,13 @@ export function SignalDetailClient({ signalId, initialReplies }: Props) {
                 </span>
                 <span
                   className="font-mono text-[8px] px-1 py-0.5"
-                  style={{ background: "#EEEDFE", color: "#534AB7" }}
+                  style={
+                    r.signature_verified
+                      ? { background: "#E1F5EE", color: "#0F6E56" }
+                      : { background: "#EEEDFE", color: "#534AB7" }
+                  }
                 >
-                  {t.walletBadge}
+                  {r.signature_verified ? t.verifiedBadge : t.walletBadge}
                 </span>
                 <span className="ml-auto font-mono text-[9px] text-muted-foreground/40">
                   {timeAgo(r.created_at)}

app/signals/page.tsx

@@ -31,6 +31,7 @@ const copy = {
     replies: "replies",
     upvotes: "upvotes",
     walletBadge: "✓ WALLET",
+    verifiedBadge: "✓ VERIFIED",
     onChain: "✓ ON-CHAIN",
     unverified: "UNVERIFIED",
     collector: "✓ COLLECTOR",
@@ -59,6 +60,7 @@ const copy = {
     replies: "respuestas",
     upvotes: "votos",
     walletBadge: "✓ WALLET",
+    verifiedBadge: "✓ VERIFICADO",
     onChain: "✓ ON-CHAIN",
     unverified: "NO_VERIFICADO",
     collector: "✓ COLECCIONISTA",
@@ -194,9 +196,13 @@ function PostCard({
           </Link>
           <span
             className="font-mono text-[9px] px-1.5 py-0.5"
-            style={{ background: "#EEEDFE", color: "#534AB7" }}
+            style={
+              signal.signature_verified
+                ? { background: "#E1F5EE", color: "#0F6E56" }
+                : { background: "#EEEDFE", color: "#534AB7" }
+            }
           >
-            {t.walletBadge}
+            {signal.signature_verified ? t.verifiedBadge : t.walletBadge}
           </span>
           {authorProfile.isCollector && (
             <span

app/tactical-command.css

@@ -100,6 +100,24 @@
   }
 }
 
+@keyframes animated-noise-drift {
+  0% {
+    background-position: 0 0;
+  }
+  25% {
+    background-position: -1px 1px;
+  }
+  50% {
+    background-position: 1px -1px;
+  }
+  75% {
+    background-position: -1px -1px;
+  }
+  100% {
+    background-position: 0 0;
+  }
+}
+
 .tactical-crt-veil {
   pointer-events: none;
   position: absolute;
@@ -1260,6 +1278,9 @@
 }
 
 @media (prefers-reduced-motion: reduce) {
+  .tactical-film-grain {
+    animation: none;
+  }
   .forge-field-ring--active {
     animation: none;
   }