diff --git a/tests/test_chat_feedback.c b/tests/test_chat_feedback.c
index 9e87fffc..464bb94f 100644
--- a/tests/test_chat_feedback.c
+++ b/tests/test_chat_feedback.c
@@ -51,8 +51,47 @@ static void sign_record(const struct UTUN_INSTANCE* author, uint64_t channel, st
     assert(sc_ed25519_sign(author->my_ed25519_privkey, body, bytes, r->signature) == SC_OK);
 }
 
-int main(void) {
+static void check_author_rejection(struct UTUN_INSTANCE* inst) {
+    sqlite3_stmt* st = NULL; uint8_t key[32], tree[64];
+    assert(member_sync_sign_pubkey(owner_private, inst->my_keys.public_key, tree) == 0);
+    assert(fb_author_key(inst, "1001", inst->node_id, key) == 0 && !memcmp(key, inst->my_ed25519_pubkey, 32));
+    assert(sqlite3_prepare_v2(inst->topo_sqlite_db, "UPDATE peers_1001 SET signature=? WHERE node_id=?", -1, &st, NULL) == SQLITE_OK);
+    uint8_t zero[64] = {0}; sqlite3_bind_blob(st, 1, zero, 64, SQLITE_STATIC); sqlite3_bind_int64(st, 2, inst->node_id);
+    assert(sqlite3_step(st) == SQLITE_DONE && fb_author_key(inst, "1001", inst->node_id, key) < 0);
+    sqlite3_reset(st); sqlite3_bind_null(st, 1);
+    assert(sqlite3_step(st) == SQLITE_DONE && fb_author_key(inst, "1001", inst->node_id, key) < 0);
+    sqlite3_reset(st); tree[0] ^= 1; sqlite3_bind_blob(st, 1, tree, 64, SQLITE_STATIC);
+    assert(sqlite3_step(st) == SQLITE_DONE && fb_author_key(inst, "1001", inst->node_id, key) < 0);
+    sqlite3_reset(st); tree[0] ^= 1;
+    assert(sqlite3_step(st) == SQLITE_DONE && fb_author_key(inst, "1001", inst->node_id, key) == 0);
+    sqlite3_finalize(st);
+    puts("PASS: root author requires a valid channel signature; zero, missing and forged certificates are rejected");
+}
+
+/* Диагностика копии профиля: без изменения записей или доступа к приватным ключам. */
+static int check_profile_authors(const char* path) {
+    struct UTUN_INSTANCE inst = {0};
+    assert(sqlite3_open_v2(path, &inst.topo_sqlite_db, SQLITE_OPEN_READONLY, NULL) == SQLITE_OK);
+    sqlite3_stmt *channels = NULL, *members = NULL;
+    assert(sqlite3_prepare_v2(inst.topo_sqlite_db, "SELECT channel_id FROM channels", -1, &channels, NULL) == SQLITE_OK);
+    int total = 0, rc;
+    while ((rc = sqlite3_step(channels)) == SQLITE_ROW) {
+        const char* channel = (const char*)sqlite3_column_text(channels, 0); char sql[256];
+        snprintf(sql, sizeof(sql), "SELECT node_id FROM peers_%s WHERE source=0", channel);
+        assert(sqlite3_prepare_v2(inst.topo_sqlite_db, sql, -1, &members, NULL) == SQLITE_OK);
+        int step;
+        while ((step = sqlite3_step(members)) == SQLITE_ROW) {
+            uint8_t key[32]; assert(fb_author_key(&inst, channel, sqlite3_column_int64(members, 0), key) == 0); total++;
+        }
+        assert(step == SQLITE_DONE); sqlite3_finalize(members); members = NULL;
+    }
+    assert(rc == SQLITE_DONE); sqlite3_finalize(channels); assert(sqlite3_close(inst.topo_sqlite_db) == SQLITE_OK);
+    printf("PASS: all %d authors in the profile have valid node keys, joins and invitation certificates\n", total); return 0;
+}
+
+int main(int argc, char** argv) {
     debug_config_init(); debug_set_level(DEBUG_LEVEL_WARN);
+    if (argc == 2) return check_profile_authors(argv[1]);
     size_t baseline = u_get_allocated_count();
     struct UASYNC* ua = uasync_create(); assert(ua);
     struct UTUN_INSTANCE source, target; setup(&source, ua); setup(&target, ua);
@@ -61,6 +100,7 @@ int main(void) {
         add_member(&source, &source, channel); add_member(&target, &source, channel);
         add_member(&source, &target, channel); add_member(&target, &target, channel);
     }
+    check_author_rejection(&source);
     uint8_t message[32], other_message[32], signature[64] = {7};
     assert(chat_message_id(1001, 123, signature, message) == 0);
     assert(chat_message_id(1002, 123, signature, other_message) == 0 && memcmp(message, other_message, 32));