diff --git a/apps/backend/src/__tests__/conversations.cache.test.ts b/apps/backend/src/__tests__/conversations.cache.test.ts
index 7e7f679..366d712 100644
--- a/apps/backend/src/__tests__/conversations.cache.test.ts
+++ b/apps/backend/src/__tests__/conversations.cache.test.ts
@@ -62,7 +62,7 @@ vi.mock('../db/schema.js', () => ({
     id: 'id',
     conversationId: 'conversationId',
     senderId: 'senderId',
-    content: 'content',
+    ciphertext: 'ciphertext',
     createdAt: 'createdAt',
     deletedAt: 'deletedAt',
   },
@@ -189,51 +189,6 @@ describe('GET /conversations — Redis caching', () => {
   });
 });
 
-describe('GET /conversations/:id/search', () => {
-  beforeEach(() => {
-    vi.clearAllMocks();
-    mockRedisInstance = { get: mockGet, setex: mockSetex, del: mockDel };
-  });
-
-  it('returns 400 when the query is empty', async () => {
-    const res = await request(makeApp()).get('/conversations/conv-1/search?q=   ');
-
-    expect(res.status).toBe(400);
-    expect(mockFindFirst).not.toHaveBeenCalled();
-    expect(mockExecute).not.toHaveBeenCalled();
-  });
-
-  it('returns 403 when the user is not a conversation member', async () => {
-    mockFindFirst.mockResolvedValue(undefined);
-
-    const res = await request(makeApp()).get('/conversations/conv-1/search?q=hello');
-
-    expect(res.status).toBe(403);
-    expect(mockExecute).not.toHaveBeenCalled();
-  });
-
-  it('returns ranked highlighted matches for conversation members', async () => {
-    const searchResults = [
-      {
-        id: 'msg-1',
-        conversationId: 'conv-1',
-        senderId: TEST_USER_ID,
-        content: 'hello from stellar',
-        snippet: '<mark>hello</mark> from stellar',
-        rank: '0.1',
-      },
-    ];
-    mockFindFirst.mockResolvedValue({ id: 'member-1' });
-    mockExecute.mockResolvedValue(searchResults);
-
-    const res = await request(makeApp()).get('/conversations/conv-1/search?q=hello');
-
-    expect(res.status).toBe(200);
-    expect(res.body).toEqual({ results: searchResults });
-    expect(mockExecute).toHaveBeenCalledTimes(1);
-  });
-});
-
 describe('GET /conversations — isArchived filter', () => {
   beforeEach(() => {
     vi.clearAllMocks();
diff --git a/apps/backend/src/__tests__/conversations.routes.test.ts b/apps/backend/src/__tests__/conversations.routes.test.ts
index f402138..aec47d1 100644
--- a/apps/backend/src/__tests__/conversations.routes.test.ts
+++ b/apps/backend/src/__tests__/conversations.routes.test.ts
@@ -54,7 +54,7 @@ vi.mock('../db/schema.js', () => ({
     id: 'id',
     conversationId: 'conversationId',
     senderId: 'senderId',
-    content: 'content',
+    ciphertext: 'ciphertext',
     createdAt: 'createdAt',
     deletedAt: 'deletedAt',
   },
@@ -138,7 +138,7 @@ describe('GET /conversations/:id', () => {
           id: 'msg-1',
           conversationId: 'conv-1',
           senderId: 'user-1',
-          content: 'hello',
+          ciphertext: 'hello',
           deletedAt: null,
           sender: {
             id: 'user-1',
@@ -157,7 +157,7 @@ describe('GET /conversations/:id', () => {
     expect(res.status).toBe(200);
     expect(res.body.id).toBe('conv-1');
     expect(res.body.messages).toHaveLength(1);
-    expect(res.body.messages[0].content).toBe('hello');
+    expect(res.body.messages[0].ciphertext).toBe('hello');
   });
 });
 
diff --git a/apps/backend/src/__tests__/messages.routes.test.ts b/apps/backend/src/__tests__/messages.routes.test.ts
index f48ae04..e39f0c6 100644
--- a/apps/backend/src/__tests__/messages.routes.test.ts
+++ b/apps/backend/src/__tests__/messages.routes.test.ts
@@ -41,7 +41,7 @@ vi.mock('../db/schema.js', () => ({
     id: 'id',
     conversationId: 'conversationId',
     senderId: 'senderId',
-    content: 'content',
+    ciphertext: 'ciphertext',
     createdAt: 'createdAt',
     deletedAt: 'deletedAt',
   },
@@ -83,7 +83,7 @@ describe('DELETE /messages/:id', () => {
       id: 'msg-1',
       conversationId: 'conv-1',
       senderId: 'user-2',
-      content: 'hello',
+      ciphertext: 'hello',
       deletedAt: null,
     });
 
@@ -98,7 +98,7 @@ describe('DELETE /messages/:id', () => {
       id: 'msg-1',
       conversationId: 'conv-1',
       senderId: 'user-1',
-      content: 'hello',
+      ciphertext: 'hello',
       deletedAt: null,
     });
 
diff --git a/apps/backend/src/db/schema.ts b/apps/backend/src/db/schema.ts
index 9e09e99..5ba4fce 100644
--- a/apps/backend/src/db/schema.ts
+++ b/apps/backend/src/db/schema.ts
@@ -67,16 +67,10 @@ export const messages = pgTable(
     senderId: uuid('sender_id')
       .notNull()
       .references(() => users.id, { onDelete: 'cascade' }),
-    content: text('content').notNull(),
+    ciphertext: text('ciphertext'),
     createdAt: timestamp('created_at').notNull().defaultNow(),
     deletedAt: timestamp('deleted_at'),
   },
-  (table) => [
-    index('messages_content_search_idx').using(
-      'gin',
-      sql`to_tsvector('english', ${table.content})`,
-    ),
-  ],
 );
 
 // ─── Devices & prekeys (issues #158, #159, #162) ─────────────────────────────
diff --git a/apps/backend/src/lib/messages.ts b/apps/backend/src/lib/messages.ts
index a07cb4c..b2b6e2a 100644
--- a/apps/backend/src/lib/messages.ts
+++ b/apps/backend/src/lib/messages.ts
@@ -1,15 +1,15 @@
 type MessageLike = {
-  content: string | null;
+  ciphertext: string | null;
   deletedAt?: Date | null;
 };
 
 export function serializeMessage<T extends MessageLike>(
   message: T,
-): Omit<T, 'deletedAt'> & { content: string | null } {
+): Omit<T, 'deletedAt'> & { ciphertext: string | null } {
   const { deletedAt, ...rest } = message;
 
   return {
     ...rest,
-    content: deletedAt ? null : message.content,
+    ciphertext: deletedAt ? null : message.ciphertext,
   };
 }
diff --git a/apps/backend/src/routes/conversations.ts b/apps/backend/src/routes/conversations.ts
index 822070f..89bb61e 100644
--- a/apps/backend/src/routes/conversations.ts
+++ b/apps/backend/src/routes/conversations.ts
@@ -14,8 +14,6 @@ export const conversationsRouter: IRouter = Router();
 
 conversationsRouter.use(requireAuth);
 
-const SEARCH_RESULT_LIMIT = 20;
-
 const conversationRelations = {
   members: {
     with: {
@@ -485,69 +483,6 @@ conversationsRouter.get('/:id/messages', async (req: AuthRequest, res) => {
   res.json({ messages: page, nextCursor });
 });
 
-conversationsRouter.get('/:id/search', async (req: AuthRequest, res) => {
-  const userId = req.auth!.userId;
-  const conversationId = req.params['id'] as string | undefined;
-  const query = typeof req.query.q === 'string' ? req.query.q.trim() : '';
-
-  if (!conversationId) {
-    res.status(400).json({ error: 'Conversation id is required' });
-    return;
-  }
-
-  if (!query) {
-    res.status(400).json({ error: 'Search query is required' });
-    return;
-  }
-
-  const membership = await db.query.conversationMembers.findFirst({
-    where: and(
-      eq(conversationMembers.conversationId, conversationId),
-      eq(conversationMembers.userId, userId),
-    ),
-  });
-
-  if (!membership) {
-    res.status(403).json({ error: 'Not a member of this conversation' });
-    return;
-  }
-
-  const results = await db.execute<{
-    id: string;
-    conversationId: string;
-    senderId: string;
-    content: string;
-    createdAt: Date;
-    snippet: string;
-    rank: string;
-  }>(sql`
-    WITH search_query AS (
-      SELECT websearch_to_tsquery('english', ${query}) AS query
-    )
-    SELECT
-      ${messages.id} AS "id",
-      ${messages.conversationId} AS "conversationId",
-      ${messages.senderId} AS "senderId",
-      ${messages.content} AS "content",
-      ${messages.createdAt} AS "createdAt",
-      ts_headline(
-        'english',
-        ${messages.content},
-        search_query.query,
-        'StartSel=<mark>, StopSel=</mark>, MaxWords=24, MinWords=8, ShortWord=3, HighlightAll=false'
-      ) AS "snippet",
-      ts_rank_cd(to_tsvector('english', ${messages.content}), search_query.query) AS "rank"
-    FROM ${messages}, search_query
-    WHERE ${messages.conversationId} = ${conversationId}
-      AND ${messages.deletedAt} IS NULL
-      AND search_query.query @@ to_tsvector('english', ${messages.content})
-    ORDER BY "rank" DESC, ${messages.createdAt} DESC
-    LIMIT ${SEARCH_RESULT_LIMIT}
-  `);
-
-  res.json({ results });
-});
-
 // PATCH /conversations/:id/settings — update muted/archived state for the authenticated user
 conversationsRouter.patch('/:id/settings', async (req: AuthRequest, res) => {
   const userId = req.auth!.userId;
diff --git a/apps/backend/src/socket/messaging.ts b/apps/backend/src/socket/messaging.ts
index 17d3bab..5c22d28 100644
--- a/apps/backend/src/socket/messaging.ts
+++ b/apps/backend/src/socket/messaging.ts
@@ -35,13 +35,13 @@ export function registerMessagingHandlers(io: Server, socket: AuthSocket): void
   });
 
   // ── send_message ───────────────────────────────────────────────────────────
-  // Payload: { conversationId: string; content: string }
+  // Payload: { conversationId: string; ciphertext: string }
   // Persists the message and broadcasts it to all room members.
-  socket.on('send_message', async (payload: { conversationId: string; content: string }) => {
-    const { conversationId, content } = payload;
+  socket.on('send_message', async (payload: { conversationId: string; ciphertext: string }) => {
+    const { conversationId, ciphertext } = payload;
 
-    if (!content?.trim()) {
-      socket.emit('error', { event: 'send_message', message: 'Content must not be empty' });
+    if (!ciphertext?.trim()) {
+      socket.emit('error', { event: 'send_message', message: 'Ciphertext must not be empty' });
       return;
     }
 
@@ -59,7 +59,7 @@ export function registerMessagingHandlers(io: Server, socket: AuthSocket): void
 
     const [message] = await db
       .insert(messages)
-      .values({ conversationId, senderId: userId, content: content.trim() })
+      .values({ conversationId, senderId: userId, ciphertext: ciphertext.trim() })
       .returning();
 
     io.to(conversationId).emit('new_message', message);
@@ -238,15 +238,15 @@ export function registerMessagingHandlers(io: Server, socket: AuthSocket): void
   });
 
   // ── ask_assistant ──────────────────────────────────────────────────────────
-  // Payload: { conversationId: string; content: string }
+  // Payload: { conversationId: string; ciphertext: string }
   // Forwards to AI agent and posts reply from reserved assistant user.
   // Rate-limit: 5 requests per user per minute.
   const ASSISTANT_USER_ID = '00000000-0000-4000-8000-000000000000';
 
-  socket.on('ask_assistant', async (payload: { conversationId: string; content: string }) => {
-    const { conversationId, content } = payload;
+  socket.on('ask_assistant', async (payload: { conversationId: string; ciphertext: string }) => {
+    const { conversationId, ciphertext } = payload;
 
-    if (!content?.trim().startsWith('@assistant')) {
+    if (!ciphertext?.trim().startsWith('@assistant')) {
       return;
     }
 
@@ -284,7 +284,7 @@ export function registerMessagingHandlers(io: Server, socket: AuthSocket): void
         method: 'POST',
         headers: { 'Content-Type': 'application/json' },
         body: JSON.stringify({
-          message: content,
+          message: ciphertext,
           conversation_id: conversationId,
         }),
       });
@@ -317,7 +317,7 @@ export function registerMessagingHandlers(io: Server, socket: AuthSocket): void
         .values({
           conversationId,
           senderId: ASSISTANT_USER_ID,
-          content: data.reply,
+          ciphertext: data.reply,
         })
         .returning();