fix(lite): classify imported keys before calling the backend

importKeyCore guessed the key type from its first character, then
retried a failed import with the other command. That retry is what sent
shielded keys to the backend's transparent-key decoder, which panicked
on them and poisoned the wallet lock. A WIF typo that was still
valid base58 also reached the backend unchecked.

- The key is classified first, and exactly one backend command runs, or
  none:
  - secret-extended-key-... and zxview... go to "import";
  - a Base58Check WIF with version 0xBC or 0x80 and the compressed flag
    goes to "timport";
  - everything else is refused before any backend call.
  There is never a retry with the other command. A testnet (0xEF) WIF
  is not accepted, because the Lite app is mainnet-only.
- New fixed, untranslated reasons: "uncompressed transparent keys are
  not supported by the Lite wallet", a full-node incoming viewing key
  (zivks) is explained as such, and anything else is "unrecognized key
  format". The key is never echoed.
- The backend's refusal while the wallet is encrypted now maps to "wallet
  is encrypted - remove encryption to import a private key". It is
  checked before "locked", because unlocking would not help.
- base58Decode reserves its buffers up front, and it and
  decodeBase58Check wipe their copies of the decoded bytes with
  sodium_memzero on every return path, since the input can be a private
  key.
- exportSeed rejects the all-zero-entropy phrase (23 x "abandon" + "art").
  A backend built before the seed-export fix returns it for a wallet
  whose lock failed halfway (seed wiped, wallet still unlocked); it is
  never a real backup and must not seed a chat identity.
- An open that the backend recovered from the .bak ("OK: recovered from
  backup; damaged file kept as <name>") is written to the lite log.

Tests: the retry control now expects one "import" and no "timport", and
"typo-key" makes no backend call; the controller's transparent-import
test uses a real compressed WIF. A new classifier test covers both WIF
versions, the shielded and viewing keys, a single call on failure, the
uncompressed, zivks, testnet, bad-flag and bad-checksum refusals, the
encrypted reason and its lite-log line, the zero-entropy seed and the
recovery log line.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/util/address_validation.cpp

@@ -21,13 +21,18 @@ constexpr const char* kBase58 =
     "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz";
 constexpr const char* kBech32 = "qpzry9x8gf2tvdw0s3jn54khce6mua7l";
 
-// Decode a Base58 string to bytes (big-endian), preserving leading-zero bytes.
+// Decode a Base58 string to bytes (big-endian), preserving leading-zero bytes. The input may be a private key
+// (WIF), so the scratch buffer is reserved up front (no reallocation leaves copies behind) and wiped on return.
 bool base58Decode(const std::string& s, std::vector<std::uint8_t>& out)
 {
     std::vector<std::uint8_t> bytes;  // little-endian during accumulation
+    bytes.reserve(s.size());          // a base58 string never decodes to more bytes than it has characters
     for (char ch : s) {
         const char* p = std::strchr(kBase58, ch);
-        if (p == nullptr || ch == '\0') return false;
+        if (p == nullptr || ch == '\0') {
+            if (!bytes.empty()) sodium_memzero(bytes.data(), bytes.size());
+            return false;
+        }
         int carry = static_cast<int>(p - kBase58);
         for (auto& b : bytes) {
             carry += static_cast<int>(b) * 58;
@@ -39,12 +44,16 @@ bool base58Decode(const std::string& s, std::vector<std::uint8_t>& out)
             carry >>= 8;
         }
     }
-    std::vector<std::uint8_t> result;
+    std::size_t leadingZeros = 0;
     for (char ch : s) {  // leading '1's map to leading zero bytes
-        if (ch == '1') result.push_back(0);
+        if (ch == '1') ++leadingZeros;
         else break;
     }
+    std::vector<std::uint8_t> result;
+    result.reserve(leadingZeros + bytes.size());
+    result.assign(leadingZeros, 0);
     result.insert(result.end(), bytes.rbegin(), bytes.rend());
+    if (!bytes.empty()) sodium_memzero(bytes.data(), bytes.size());
     out = std::move(result);
     return true;
 }
@@ -81,15 +90,23 @@ bool decodeBase58Check(const std::string& s, std::vector<std::uint8_t>& payloadO
     if (s.size() < 5 || s.size() > 256) return false;
     std::vector<std::uint8_t> data;
     if (!base58Decode(s, data)) return false;
-    if (data.size() < 5) return false;  // need at least version(1) + checksum(4)
+    // `data` may hold a private key (a WIF): wipe it on every return path.
+    if (data.size() < 5) {  // need at least version(1) + checksum(4)
+        if (!data.empty()) sodium_memzero(data.data(), data.size());
+        return false;
+    }
 
     const std::size_t payloadLen = data.size() - 4;
     unsigned char h1[crypto_hash_sha256_BYTES];
     unsigned char h2[crypto_hash_sha256_BYTES];
     crypto_hash_sha256(h1, data.data(), payloadLen);
     crypto_hash_sha256(h2, h1, sizeof(h1));
-    if (std::memcmp(h2, data.data() + payloadLen, 4) != 0) return false;
+    if (std::memcmp(h2, data.data() + payloadLen, 4) != 0) {
+        sodium_memzero(data.data(), data.size());
+        return false;
+    }
     payloadOut.assign(data.begin(), data.begin() + payloadLen);
+    sodium_memzero(data.data(), data.size());
     return true;
 }
 

src/wallet/lite_wallet_controller.cpp

@@ -7,6 +7,7 @@
 #include "lite_diagnostics.h"
 #include "lite_result_parsers.h"
 #include "../data/wallet_state.h"
+#include "../util/address_validation.h"
 
 #include <algorithm>
 #include <chrono>
@@ -40,6 +41,24 @@ std::string extractJsonError(const nlohmann::json& value)
     return e.is_string() ? e.get<std::string>() : e.dump();
 }
 
+// True for the BIP39 phrase of all-zero entropy (23 x "abandon", then "art"), compared word by word in place so the
+// secret is never copied. A real wallet has this seed with probability 2^-256.
+bool isZeroEntropySeedPhrase(const std::string& phrase)
+{
+    const auto isSpace = [](char c) { return c == ' ' || c == '\t' || c == '\n' || c == '\r'; };
+    std::size_t i = 0, words = 0;
+    while (true) {
+        while (i < phrase.size() && isSpace(phrase[i])) ++i;
+        if (i == phrase.size()) break;
+        std::size_t end = i;
+        while (end < phrase.size() && !isSpace(phrase[end])) ++end;
+        ++words;
+        if (words > 24 || phrase.compare(i, end - i, words < 24 ? "abandon" : "art") != 0) return false;
+        i = end;
+    }
+    return words == 24;
+}
+
 // Parse a send/shield response: success is {"txid":".."}, failure is {"error":".."} (NOT an
 // "Error:"-prefixed string), and malformed args make the backend return plain-text help.
 LiteBroadcastResult parseBroadcastResponse(const LiteBridgeStringResult& bridgeCall)
@@ -169,6 +188,8 @@ std::string liteImportFailureReason(const std::string& backendError)
 {
     const auto has = [&backendError](const char* s) { return backendError.find(s) != std::string::npos; };
     if (has("was not recognized")) return "unrecognized key format";
+    // Checked before "locked": unlocking does not help, the backend refuses private-key imports while encrypted.
+    if (has("encrypted")) return "wallet is encrypted - remove encryption to import a private key";
     if (has("locked")) return "wallet is locked";
     if (has("already exists")) return "key already exists";
     if (has("decode")) return "key could not be decoded";
@@ -178,15 +199,31 @@ std::string liteImportFailureReason(const std::string& backendError)
 // `key` must be non-empty; it is wiped before returning. A failure's error is a fixed reason, never backend text.
 LiteImportResult importKeyCore(LiteClientBridge& bridge, std::string& key, const std::atomic<bool>* retired = nullptr)
 {
-    // Transparent WIFs begin with U/5/K/L (TImportCommand); shielded keys begin with
-    // "secret-..." / viewing keys "zxview...", so this prefix check usually won't collide.
+    // Classify first, then call exactly one backend command, or none (C251). There is no retry with the other
+    // command: the wrong command never imported the key anyway, and that retry is what fed shielded keys to the
+    // backend's transparent-key decoder.
     // NB: the lite/SDXL backend's viewing key is an *extended full* viewing key ("zxviews…",
     // hrp_sapling_viewing_key), which is genuinely correct here — do NOT "harmonize" this with the
     // full node, whose z_importviewingkey takes an *incoming* viewing key ("zivks…") instead. The
-    // two variants accept different viewing-key forms; a VK is not portable between them. Regardless,
-    // the two-command fallback below means a mis-guessed prefix never rejects an otherwise-valid key.
-    const char first = key[0];
-    const bool transparentFirst = (first == 'U' || first == '5' || first == 'K' || first == 'L');
+    // two variants accept different viewing-key forms; a VK is not portable between them, so a
+    // "zivks…" key is refused here with a fixed reason.
+    enum class Kind { Shielded, FullViewing, FullNodeIvk, TransparentWif, UncompressedWif, Unknown };
+    Kind kind = Kind::Unknown;
+    if (key.rfind("secret-extended-key-", 0) == 0)  kind = Kind::Shielded;
+    else if (key.rfind("zxview", 0) == 0)           kind = Kind::FullViewing;   // SDXL extended full viewing key
+    else if (key.rfind("zivks", 0) == 0)            kind = Kind::FullNodeIvk;   // full-node incoming VK: not importable
+    else {
+        // A transparent WIF is Base58Check with the mainnet (0xBC) or Bitcoin-style (0x80) version byte and the
+        // compressed-key flag. The Lite app is mainnet-only, so a testnet (0xEF) WIF is not accepted.
+        std::vector<std::uint8_t> payload;
+        if (util::decodeBase58Check(key, payload)) {
+            if (payload.size() == 34 && payload[33] == 0x01 && (payload[0] == 0xBC || payload[0] == 0x80))
+                kind = Kind::TransparentWif;
+            else if (payload.size() == 33)
+                kind = Kind::UncompressedWif;
+        }
+        if (!payload.empty()) sodium_memzero(payload.data(), payload.size());
+    }
 
     auto runImport = [&](const char* command) -> LiteImportResult {
         LiteImportResult r;
@@ -209,18 +246,23 @@ LiteImportResult importKeyCore(LiteClientBridge& bridge, std::string& key, const
         return r;
     };
 
-    LiteImportResult out = runImport(transparentFirst ? "timport" : "import");
-    if (!out.ok && liteOpRetired(retired)) {
-        out.error = kLiteOpRetiredError;   // the fallback would import the key on the NEXT server's client
-    } else if (!out.ok) {
-        // The single-char heuristic can mis-route (e.g. testnet/regtest WIFs). Try the other
-        // command before giving up — the wrong command rejects the key (each validates the
-        // encoding), it never imports it as the wrong type.
-        LiteImportResult alt = runImport(transparentFirst ? "import" : "timport");
-        if (alt.ok) out = alt;
+    LiteImportResult out;
+    switch (kind) {
+        case Kind::Shielded:
+        case Kind::FullViewing:    out = runImport("import"); break;
+        case Kind::TransparentWif: out = runImport("timport"); break;
+        case Kind::FullNodeIvk:
+            out.error = "this is a full-node incoming viewing key (zivks); the Lite wallet needs an extended viewing key "
+                        "(zxviews)";
+            break;
+        case Kind::UncompressedWif:
+            out.error = "uncompressed transparent keys are not supported by the Lite wallet";
+            break;
+        default: out.error = "unrecognized key format"; break;
     }
+    if (!out.ok && liteOpRetired(retired)) out.error = kLiteOpRetiredError;
     if (!out.ok) liteLog("Key import failed: " + out.error);  // a fixed reason: the backend's text can repeat the key
-    secureWipeLiteSecret(key);  // wipe our copy after both attempts
+    secureWipeLiteSecret(key);  // wipe our copy
     return out;
 }
 
@@ -535,6 +577,9 @@ bool LiteWalletController::beginAsyncLifecycle(bool create)
             if (create) secureWipeLiteSecret(call.value);
             if (ready) {
                 liteLog("  " + url + ": connected");
+                // s2-D14: an open that fell back to the backup reports "OK: recovered from backup; damaged file kept
+                // as <name>". Never for create: its value was the seed (wiped above).
+                if (!create && call.value != "OK") liteLog("  " + call.value);
                 outcome.ok = true;
                 outcome.serverUrl = url;
                 break;
@@ -1156,6 +1201,13 @@ LiteSeedResult LiteWalletController::exportSeed()
                 if (j.contains("birthday") && j.at("birthday").is_number_unsigned()) {
                     out.birthday = j.at("birthday").get<std::uint64_t>();
                 }
+                if (isZeroEntropySeedPhrase(out.seedPhrase)) {
+                    // A backend built before the seed-export fix returns this for a locked wallet whose seed is
+                    // wiped. It is never the real backup, so it must not be shown or used to derive anything.
+                    secureWipeLiteSecret(out.seedPhrase);
+                    out.error = "backend returned the all-zero placeholder seed (is the wallet locked?)";
+                    return out;
+                }
                 out.ok = !out.seedPhrase.empty();
                 if (!out.ok) out.error = "backend returned an empty seed";
                 return out;

tests/fake_lite_backend.h

@@ -49,6 +49,7 @@ inline std::atomic<long> g_liteFakeBalanceEntered{0};    // calls that reached "
 inline std::atomic<bool> g_liteFakeBlockEncrypt{false};  // "encrypt" blocks (before changing state)
 inline std::atomic<bool> g_liteFakeBlockImport{false};   // "import"/"timport" block
 inline std::atomic<bool> g_liteFakeImportFails{false};   // "import"/"timport" reject the key (real do_import_key shape)
+inline std::atomic<bool> g_liteFakeImportEncrypted{false}; // "import"/"timport" refuse: the wallet is encrypted
 inline std::atomic<bool> g_liteFakeLogEnabled{false};
 inline std::mutex g_liteFakeLogMutex;
 inline std::vector<std::string> g_liteFakeCommandLog;    // execute() command names, in order, while enabled
@@ -73,6 +74,10 @@ inline long liteFakeCount(const std::vector<std::string>& log, const char* comma
 inline std::string g_liteFakeDeadServerSubstr;
 // initialize_existing returns a warming-up (-28) error for URLs containing this substring.
 inline std::string g_liteFakeWarmupServerSubstr;
+// When non-empty, initialize_existing returns "OK: <note>" (a wallet recovered from its backup, s2-D14).
+inline std::string g_liteFakeOpenRecoveredNote;
+// When non-empty, "seed" returns this phrase instead of the default one.
+inline std::string g_liteFakeSeedPhrase;
 
 inline void resetLiteFakeCounters()
 {
@@ -81,6 +86,8 @@ inline void resetLiteFakeCounters()
     g_liteFakeShutdownCalled = false;
     g_liteFakeDeadServerSubstr.clear();
     g_liteFakeWarmupServerSubstr.clear();
+    g_liteFakeOpenRecoveredNote.clear();
+    g_liteFakeSeedPhrase.clear();
     g_liteFakeBlockNew = false;
     g_liteFakeBlockSave = false;
     g_liteFakeBlockBalance = false;
@@ -88,6 +95,7 @@ inline void resetLiteFakeCounters()
     g_liteFakeBlockEncrypt = false;
     g_liteFakeBlockImport = false;
     g_liteFakeImportFails = false;
+    g_liteFakeImportEncrypted = false;
     g_liteFakeLogEnabled = false;
     (void)liteFakeTakeLog();
 }
@@ -142,6 +150,7 @@ inline char* liteFakeInitExisting(bool, const char* server)
             return liteFakeDup("Error: could not connect to server");  // bridge maps to ok=false
         }
     }
+    if (!g_liteFakeOpenRecoveredNote.empty()) return liteFakeDup(("OK: " + g_liteFakeOpenRecoveredNote).c_str());
     return liteFakeDup("OK");
 }
 inline char* liteFakeExecute(const char* command, const char* args)
@@ -207,11 +216,18 @@ inline char* liteFakeExecute(const char* command, const char* args)
         if (std::strcmp(c, "export") == 0)
             return liteFakeDup("[{\"address\":\"zs1fakeaddr\",\"private_key\":\"SECRET-ZKEY\","
                                "\"viewing_key\":\"zxviewsFAKE\"}]");
-        if (std::strcmp(c, "seed") == 0)
+        if (std::strcmp(c, "seed") == 0) {
+            if (!g_liteFakeSeedPhrase.empty())
+                return liteFakeDup(("{\"seed\":\"" + g_liteFakeSeedPhrase + "\",\"birthday\":0}").c_str());
             return liteFakeDup("{\"seed\":\"fake seed phrase words\",\"birthday\":0}");
+        }
         // import (shielded key) / timport (transparent WIF): do_import_* pretty-print JSON.
         if (std::strcmp(c, "import") == 0 || std::strcmp(c, "timport") == 0) {
             liteFakeWaitWhile(g_liteFakeBlockImport);
+            // The real refusal (lightclient do_import_tk/do_import_sk, prefixed by the console command).
+            if (g_liteFakeImportEncrypted.load())
+                return liteFakeDup("Error: Can't import a private key while the wallet is encrypted - remove "
+                                   "encryption, import, then encrypt again");
             // The real do_import_key error REPEATS the key: "Error: '<key>' was not recognized as ...".
             if (g_liteFakeImportFails.load())
                 return liteFakeDup((std::string("Error: '") + (args ? args : "") +

tests/test_phase4.cpp

@@ -8249,10 +8249,12 @@ void testLiteWalletControllerM4()
         EXPECT_TRUE(r.detail.find("zs1imported") != std::string::npos);
     }
 
-    // import transparent WIF (begins with K) -> "timport"
+    // import transparent WIF (Base58Check, version 0x80, compressed; key = 1) -> "timport"
     {
+        std::vector<std::uint8_t> payload;
+        EXPECT_TRUE(dragonx::util::decodeBase58Check("KwDiBf89QgGbjEhKnhXJuH7LrciVrZi3qYjgd9M7rFU73sVHnoWn", payload));
         auto c = openController();
-        const auto r = c->importKey("Kx1faketransparentwif");
+        const auto r = c->importKey("KwDiBf89QgGbjEhKnhXJuH7LrciVrZi3qYjgd9M7rFU73sVHnoWn");
         EXPECT_TRUE(r.ok);
     }
 
@@ -9750,7 +9752,8 @@ void testLiteWalletControllerRetireStopsOpFollowUps()
         EXPECT_EQ(n, 1);
         dragonx::test::g_liteFakeLogEnabled = false;
     }
-    {   // control: an unrecognized key is retried with the other import command
+    {   // control: a failed shielded import calls the backend once and is never retried with the other command;
+        // a key no classifier recognizes calls neither command
         auto c = openController();
         dragonx::test::g_liteFakeImportFails = true;
         int n = 0; bool ok = true;
@@ -9762,12 +9765,22 @@ void testLiteWalletControllerRetireStopsOpFollowUps()
         std::vector<std::string> log;
         drainLog(log);
         EXPECT_EQ(dragonx::test::liteFakeCount(log, "import"), 1L);
-        EXPECT_EQ(dragonx::test::liteFakeCount(log, "timport"), 1L);
+        EXPECT_EQ(dragonx::test::liteFakeCount(log, "timport"), 0L);
+        int n2 = 0; LiteImportResult got; got.ok = true;
+        EXPECT_TRUE(c->importKeyAsync("typo-key", [&](const LiteImportResult& r) { ++n2; got = r; }));
+        EXPECT_TRUE(c->waitWalletOpsIdle(std::chrono::milliseconds(3000)));
+        c->pumpWalletOps();
+        EXPECT_EQ(n2, 1);
+        EXPECT_FALSE(got.ok);
+        EXPECT_EQ(got.error, std::string("unrecognized key format"));
+        drainLog(log);
+        EXPECT_EQ(dragonx::test::liteFakeCount(log, "import"), 1L);
+        EXPECT_EQ(dragonx::test::liteFakeCount(log, "timport"), 0L);
         c.reset();
         dragonx::test::g_liteFakeImportFails = false;
         dragonx::test::g_liteFakeLogEnabled = false;
     }
-    {   // the first import attempt in flight (and failing) -> retire -> the fallback never runs
+    {   // the single import call in flight (and failing) -> retire -> delivered once, never retried with timport
         auto c = openController();
         dragonx::test::g_liteFakeImportFails = true;
         dragonx::test::g_liteFakeBlockImport = true;
@@ -9825,7 +9838,7 @@ void testLiteWalletControllerImportErrorNeverRepeatsKey()
         return false;
     };
 
-    {   // synchronous: both attempts fail; neither the result nor the log carries the key
+    {   // synchronous: the single import call fails; neither the result nor the log carries the key
         const auto r = c.importKey("secret-extended-key-typoMARKSYNC");
         EXPECT_FALSE(r.ok);
         EXPECT_EQ(r.error, std::string("unrecognized key format"));
@@ -9846,6 +9859,173 @@ void testLiteWalletControllerImportErrorNeverRepeatsKey()
     dragonx::test::g_liteFakeImportFails = false;
 }
 
+// C251/C252 (X1): importKeyCore classifies the key, then calls exactly one backend command or none, never the other
+// command as a retry. Refusals are fixed reasons. Also the encrypted-wallet reason (s1-D4), the zero-entropy seed
+// guard and the logged backup recovery (s2-D14).
+void testLiteWalletControllerImportClassifier()
+{
+    using namespace dragonx::wallet;
+    const auto caps = makeWalletCapabilities(WalletBuildKind::Lite, false, true);
+    const auto conn = defaultLiteConnectionSettings();
+    dragonx::test::resetLiteFakeCounters();
+    dragonx::test::g_liteFakeEncrypted = false;
+    dragonx::test::g_liteFakeLocked = false;
+    dragonx::test::g_liteFakeWalletExists = true;
+    const auto logMentions = [](const std::string& needle) {
+        for (const auto& line : LiteDiagnostics::instance().snapshot())
+            if (line.find(needle) != std::string::npos) return true;
+        return false;
+    };
+    auto c = std::make_unique<LiteWalletController>(caps, conn,
+                                                    LiteClientBridge::fromApi(dragonx::test::makeFakeLiteApi()));
+    EXPECT_TRUE(c->createWallet(LiteWalletCreateRequest{}).walletReady);
+    for (int i = 0; i < 400 && !c->syncComplete(); ++i) std::this_thread::sleep_for(std::chrono::milliseconds(5));
+
+    struct Outcome { LiteImportResult r; long imports = 0; long timports = 0; };
+    const auto importCounting = [&c](const std::string& key) {
+        (void)dragonx::test::liteFakeTakeLog();
+        dragonx::test::g_liteFakeLogEnabled = true;
+        Outcome o;
+        o.r = c->importKey(key);
+        dragonx::test::g_liteFakeLogEnabled = false;
+        const auto log = dragonx::test::liteFakeTakeLog();
+        o.imports = dragonx::test::liteFakeCount(log, "import");
+        o.timports = dragonx::test::liteFakeCount(log, "timport");
+        return o;
+    };
+    const std::string kCompressed80 = "KwDiBf89QgGbjEhKnhXJuH7LrciVrZi3qYjgd9M7rFU73sVHnoWn";   // key = 1, 0x80
+    const std::string kCompressedBC = "Up1YVLk7uuErCHVQyFCtfinZngmdwfyfc47WCQ8oJxgowjVzNeqs";   // key = 1, 0xBC
+    const std::string kUncompressed = "5HpHagT65TZzG1PH3CSu63k8DbpvD8s5ip4nEB3kEsreAnchuDf";    // key = 1, 0x80
+    const std::string kTestnet      = "cMahea7zqjxrtgAbB7LSGbcQUr1uX1ojuat9jZodMN87JcbXMTcA";   // key = 1, 0xEF
+    const std::string kBadFlag      = "Up1YVLk7uuErCHVQyFCtfinZngmdwfyfc47WCQ8oJxgowjcCjSha";   // 0xBC, flag 0x02
+    {
+        std::vector<std::uint8_t> p;
+        EXPECT_TRUE(dragonx::util::decodeBase58Check(kCompressed80, p));
+        EXPECT_TRUE(p.size() == 34 && p[0] == 0x80 && p[33] == 0x01);
+        EXPECT_TRUE(dragonx::util::decodeBase58Check(kCompressedBC, p));
+        EXPECT_TRUE(p.size() == 34 && p[0] == 0xBC && p[33] == 0x01);
+        EXPECT_TRUE(dragonx::util::decodeBase58Check(kUncompressed, p));
+        EXPECT_EQ(p.size(), std::size_t(33));
+        EXPECT_TRUE(dragonx::util::decodeBase58Check(kTestnet, p));
+        EXPECT_TRUE(p.size() == 34 && p[0] == 0xEF);
+        EXPECT_TRUE(dragonx::util::decodeBase58Check(kBadFlag, p));
+        EXPECT_TRUE(p.size() == 34 && p[33] == 0x02);
+        // one changed character breaks the checksum
+        EXPECT_FALSE(dragonx::util::decodeBase58Check(kCompressed80.substr(0, kCompressed80.size() - 1) + "m", p));
+    }
+
+    {   // compressed WIFs (0x80 and the DragonX 0xBC) -> "timport" only
+        for (const auto& wif : {kCompressed80, kCompressedBC}) {
+            const auto o = importCounting(wif);
+            EXPECT_TRUE(o.r.ok);
+            EXPECT_EQ(o.timports, 1L);
+            EXPECT_EQ(o.imports, 0L);
+        }
+    }
+    {   // shielded spending key and extended full viewing key -> "import" only
+        for (const char* key : {"secret-extended-key-main1fakeshieldedkey", "zxviews1fakeviewingkey"}) {
+            const auto o = importCounting(key);
+            EXPECT_TRUE(o.r.ok);
+            EXPECT_EQ(o.imports, 1L);
+            EXPECT_EQ(o.timports, 0L);
+        }
+    }
+    {   // a failed import calls the backend exactly once (it was retried with the other command before)
+        dragonx::test::g_liteFakeImportFails = true;
+        const auto z = importCounting("secret-extended-key-main1typo");
+        EXPECT_FALSE(z.r.ok);
+        EXPECT_EQ(z.imports + z.timports, 1L);
+        const auto t = importCounting(kCompressed80);
+        EXPECT_FALSE(t.r.ok);
+        EXPECT_EQ(t.timports, 1L);
+        EXPECT_EQ(t.imports, 0L);
+        dragonx::test::g_liteFakeImportFails = false;
+    }
+    {   // refused before any backend call, with a fixed reason
+        LiteDiagnostics::instance().clear();
+        const auto u = importCounting(kUncompressed);
+        EXPECT_FALSE(u.r.ok);
+        EXPECT_EQ(u.r.error, std::string("uncompressed transparent keys are not supported by the Lite wallet"));
+        EXPECT_EQ(u.imports + u.timports, 0L);
+        EXPECT_TRUE(logMentions("Key import failed: uncompressed transparent keys are not supported"));
+
+        const auto ivk = importCounting("zivks1fakeincomingviewingkeyfromthefullnode");
+        EXPECT_FALSE(ivk.r.ok);
+        EXPECT_TRUE(ivk.r.error.find("full-node incoming viewing key (zivks)") != std::string::npos);
+        EXPECT_EQ(ivk.imports + ivk.timports, 0L);
+
+        for (const std::string& bad : {kTestnet, kBadFlag, kCompressed80.substr(0, kCompressed80.size() - 1) + "m",
+                                       std::string("typo-key"), std::string("Kx1faketransparentwif")}) {
+            const auto o = importCounting(bad);
+            EXPECT_FALSE(o.r.ok);
+            EXPECT_EQ(o.r.error, std::string("unrecognized key format"));
+            EXPECT_EQ(o.imports + o.timports, 0L);
+        }
+    }
+    {   // the backend's encrypted-wallet refusal maps to its own reason, ahead of "locked"
+        LiteDiagnostics::instance().clear();
+        dragonx::test::g_liteFakeImportEncrypted = true;
+        const auto z = importCounting("secret-extended-key-main1fakeshieldedkey");
+        EXPECT_FALSE(z.r.ok);
+        EXPECT_EQ(z.r.error, std::string("wallet is encrypted - remove encryption to import a private key"));
+        EXPECT_EQ(z.imports, 1L);
+        const auto t = importCounting(kCompressedBC);
+        EXPECT_FALSE(t.r.ok);
+        EXPECT_EQ(t.r.error, std::string("wallet is encrypted - remove encryption to import a private key"));
+        EXPECT_EQ(t.timports, 1L);
+        EXPECT_TRUE(logMentions("Key import failed: wallet is encrypted"));
+        dragonx::test::g_liteFakeImportEncrypted = false;
+    }
+
+    {   // seed export never returns the all-zero-entropy phrase (a stale backend's answer for a locked wallet)
+        std::string zero;
+        for (int i = 0; i < 23; ++i) zero += "abandon ";
+        dragonx::test::g_liteFakeSeedPhrase = zero + "art";
+        auto s = c->exportSeed();
+        EXPECT_FALSE(s.ok);
+        EXPECT_TRUE(s.seedPhrase.empty());
+        EXPECT_FALSE(s.error.empty());
+        // near misses are real phrases
+        dragonx::test::g_liteFakeSeedPhrase = zero + "about";
+        s = c->exportSeed();
+        EXPECT_TRUE(s.ok);
+        dragonx::test::g_liteFakeSeedPhrase = zero + "art art";
+        s = c->exportSeed();
+        EXPECT_TRUE(s.ok);
+        dragonx::test::g_liteFakeSeedPhrase.clear();
+        s = c->exportSeed();
+        EXPECT_TRUE(s.ok);
+        EXPECT_EQ(s.seedPhrase, std::string("fake seed phrase words"));
+    }
+    c.reset();
+
+    {   // s2-D14: an open that recovered from the backup is logged; a create never logs its response (the seed)
+        LiteDiagnostics::instance().clear();
+        dragonx::test::g_liteFakeOpenRecoveredNote =
+            "recovered from backup; damaged file kept as silentdragonxlite-wallet.dat.corrupt-1700000000";
+        LiteWalletController opened(caps, conn, LiteClientBridge::fromApi(dragonx::test::makeFakeLiteApi()));
+        EXPECT_TRUE(opened.beginOpenExisting());
+        for (int i = 0; i < 400 && opened.openInProgress(); ++i) std::this_thread::sleep_for(std::chrono::milliseconds(5));
+        opened.pumpAsyncOpen();
+        EXPECT_TRUE(opened.walletOpen());
+        EXPECT_TRUE(logMentions("OK: recovered from backup; damaged file kept as silentdragonxlite-wallet.dat.corrupt-"));
+        dragonx::test::g_liteFakeOpenRecoveredNote.clear();
+    }
+    {
+        LiteDiagnostics::instance().clear();
+        LiteWalletController created(caps, conn, LiteClientBridge::fromApi(dragonx::test::makeFakeLiteApi()));
+        EXPECT_TRUE(created.beginCreateWallet());
+        for (int i = 0; i < 400 && created.openInProgress(); ++i) std::this_thread::sleep_for(std::chrono::milliseconds(5));
+        created.pumpAsyncOpen();
+        EXPECT_TRUE(created.walletOpen());
+        EXPECT_FALSE(logMentions("fake seed phrase words"));
+        for (const auto& line : LiteDiagnostics::instance().snapshot()) {
+            const std::string msg = line.size() > 10 ? line.substr(10) : line;   // drop the "HH:MM:SS  " stamp
+            EXPECT_TRUE(msg != "  " && msg != "  OK");
+        }
+    }
+}
+
 void testLiteWalletControllerEncryptsBeforeSyncStarts()
 {
     using namespace dragonx::wallet;
@@ -15554,6 +15734,7 @@ int main()
     testLiteWalletControllerRetire();
     testLiteWalletControllerRetireStopsOpFollowUps();
     testLiteWalletControllerImportErrorNeverRepeatsKey();
+    testLiteWalletControllerImportClassifier();
     testLiteWalletControllerEncryptsBeforeSyncStarts();
     testLiteWalletControllerWorkerBacksOffOnSyncReadFailure();
     testLiteWalletControllerDestroyWithBlockedOp();