Add BIP39 and BIP32 foundation tests (#83)

Co-authored-by: Gilcimar Duarte <ti@gpm.infra>

7 files changed, 2631 insertions, 3 deletions

diff --git a/Makefile b/Makefile
index 970114d..d436885 100644
--- a/Makefile
+++ b/Makefile
@@ -2,6 +2,7 @@
 #
 #   make linux    build Bitflash-*-x86_64.AppImage
 #   make windows  build Bitflash-*-windows.zip (from MSYS2 UCRT64)
+#   make tests    build and run standalone unit tests
 #   make clean    remove build artifacts
 
 ROOT    := $(shell pwd)
@@ -156,5 +157,8 @@ clean:
         rm -f Bitflash-*.AppImage Bitflash-*.zip
         rm -rf Bitflash-*-windows
 
+tests:
+        $(MAKE) -C src -f Makefile tests
+
 .PHONY: linux windows clean appimage \
-        deps-linux deps-windows deps-apt deps-secp256k1 deps-randomx
+        tests deps-linux deps-windows deps-apt deps-secp256k1 deps-randomx
diff --git a/src/Makefile b/src/Makefile
index f0c6706..4e104c0 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -121,4 +121,10 @@ bitflash-node: $(NODE_ONLY_OBJS)
         @echo "Built: bitflash-node (headless, no libGL needed)"
 
 clean:
-        rm -rf obj obj-node bitflash bitflash-node
+        rm -rf obj obj-node bitflash bitflash-node test_bip32
+
+test_bip32: test_bip32.cpp bip32.cpp bip32.h bip39_english.h
+        $(CXX) $(CXXFLAGS) -o $@ test_bip32.cpp bip32.cpp -lssl -lcrypto
+
+tests: test_bip32
+        ./test_bip32
diff --git a/src/bip32.cpp b/src/bip32.cpp
new file mode 100644
index 0000000..6423974
--- /dev/null
+++ b/src/bip32.cpp
@@ -0,0 +1,366 @@
+// Copyright (c) 2026 Bitflash developers
+// Distributed under the MIT/X11 software license.
+
+#include "bip32.h"
+#include "bip39_english.h"
+
+#include <openssl/bn.h>
+#include <openssl/crypto.h>
+#include <openssl/ec.h>
+#include <openssl/evp.h>
+#include <openssl/hmac.h>
+#include <openssl/obj_mac.h>
+#include <openssl/rand.h>
+#include <openssl/sha.h>
+
+#include <algorithm>
+#include <cctype>
+#include <cstring>
+#include <map>
+#include <sstream>
+
+namespace bitflash
+{
+
+static bool IsSupportedEntropySize(size_t n)
+{
+    return n == 16 || n == 20 || n == 24 || n == 28 || n == 32;
+}
+
+static bool GetBit(const unsigned char* data, size_t bit)
+{
+    return (data[bit / 8] >> (7 - (bit % 8))) & 1;
+}
+
+static void AppendBits(std::vector<bool>& out, const unsigned char* data,
+                       size_t nBits)
+{
+    for (size_t i = 0; i < nBits; i++)
+        out.push_back(GetBit(data, i));
+}
+
+static std::string NormalizeMnemonic(const std::string& in)
+{
+    std::string out;
+    bool inSpace = true;
+    for (unsigned char c : in)
+    {
+        if (std::isspace(c))
+        {
+            if (!inSpace)
+                out.push_back(' ');
+            inSpace = true;
+        }
+        else
+        {
+            out.push_back((char)std::tolower(c));
+            inSpace = false;
+        }
+    }
+    if (!out.empty() && out.back() == ' ')
+        out.pop_back();
+    return out;
+}
+
+static std::vector<std::string> SplitWords(const std::string& phrase)
+{
+    std::vector<std::string> words;
+    std::istringstream in(phrase);
+    std::string word;
+    while (in >> word)
+        words.push_back(word);
+    return words;
+}
+
+static const std::map<std::string, int>& WordIndex()
+{
+    static std::map<std::string, int> m;
+    if (m.empty())
+    {
+        for (int i = 0; i < 2048; i++)
+            m[BIP39_ENGLISH_WORDS[i]] = i;
+    }
+    return m;
+}
+
+static bool IsValidPrivateKey(const std::vector<unsigned char>& key)
+{
+    if (key.size() != 32)
+        return false;
+    bool fNonZero = false;
+    for (unsigned char c : key)
+        fNonZero = fNonZero || c != 0;
+    if (!fNonZero)
+        return false;
+
+    bool ok = false;
+    BIGNUM* bn = BN_bin2bn(&key[0], 32, NULL);
+    BIGNUM* order = BN_new();
+    EC_GROUP* group = EC_GROUP_new_by_curve_name(NID_secp256k1);
+    if (bn && order && group && EC_GROUP_get_order(group, order, NULL))
+        ok = BN_cmp(bn, order) < 0;
+    BN_free(bn);
+    BN_free(order);
+    EC_GROUP_free(group);
+    return ok;
+}
+
+static bool HmacSha512(const unsigned char* key, int keyLen,
+                       const unsigned char* data, size_t dataLen,
+                       unsigned char out[64])
+{
+    unsigned int len = 64;
+    return HMAC(EVP_sha512(), key, keyLen, data, dataLen, out, &len) != NULL &&
+           len == 64;
+}
+
+bool BIP39EntropyToMnemonic(const std::vector<unsigned char>& entropy,
+                            std::string& mnemonicOut,
+                            std::string& errorOut)
+{
+    mnemonicOut.clear();
+    errorOut.clear();
+    if (!IsSupportedEntropySize(entropy.size()))
+    {
+        errorOut = "entropy must be 128, 160, 192, 224, or 256 bits";
+        return false;
+    }
+
+    unsigned char checksum[SHA256_DIGEST_LENGTH];
+    SHA256(&entropy[0], entropy.size(), checksum);
+
+    const size_t entropyBits = entropy.size() * 8;
+    const size_t checksumBits = entropyBits / 32;
+
+    std::vector<bool> bits;
+    bits.reserve(entropyBits + checksumBits);
+    AppendBits(bits, &entropy[0], entropyBits);
+    AppendBits(bits, checksum, checksumBits);
+
+    const size_t words = bits.size() / 11;
+    for (size_t i = 0; i < words; i++)
+    {
+        int idx = 0;
+        for (int j = 0; j < 11; j++)
+            idx = (idx << 1) | (bits[i * 11 + j] ? 1 : 0);
+        if (i != 0)
+            mnemonicOut += " ";
+        mnemonicOut += BIP39_ENGLISH_WORDS[idx];
+    }
+    return true;
+}
+
+bool BIP39GenerateMnemonic(std::string& mnemonicOut,
+                           std::string& errorOut,
+                           unsigned int entropyBytes)
+{
+    mnemonicOut.clear();
+    errorOut.clear();
+    if (!IsSupportedEntropySize(entropyBytes))
+    {
+        errorOut = "entropy must be 16, 20, 24, 28, or 32 bytes";
+        return false;
+    }
+
+    std::vector<unsigned char> entropy(entropyBytes);
+    if (RAND_bytes(&entropy[0], entropy.size()) != 1)
+    {
+        errorOut = "RAND_bytes failed";
+        return false;
+    }
+    bool ok = BIP39EntropyToMnemonic(entropy, mnemonicOut, errorOut);
+    OPENSSL_cleanse(&entropy[0], entropy.size());
+    return ok;
+}
+
+bool BIP39ValidateMnemonic(const std::string& mnemonic,
+                           std::string& normalizedOut,
+                           std::string& errorOut)
+{
+    normalizedOut = NormalizeMnemonic(mnemonic);
+    errorOut.clear();
+    std::vector<std::string> words = SplitWords(normalizedOut);
+    const size_t nWords = words.size();
+    if (nWords != 12 && nWords != 15 && nWords != 18 && nWords != 21 && nWords != 24)
+    {
+        errorOut = "mnemonic must contain 12, 15, 18, 21, or 24 words";
+        return false;
+    }
+
+    const std::map<std::string, int>& index = WordIndex();
+    std::vector<bool> bits;
+    bits.reserve(nWords * 11);
+    for (const std::string& word : words)
+    {
+        std::map<std::string, int>::const_iterator mi = index.find(word);
+        if (mi == index.end())
+        {
+            errorOut = "mnemonic contains a word outside the BIP39 English list";
+            return false;
+        }
+        int value = mi->second;
+        for (int i = 10; i >= 0; i--)
+            bits.push_back(((value >> i) & 1) != 0);
+    }
+
+    const size_t totalBits = bits.size();
+    const size_t entropyBits = totalBits * 32 / 33;
+    const size_t checksumBits = totalBits - entropyBits;
+    std::vector<unsigned char> entropy(entropyBits / 8, 0);
+    for (size_t i = 0; i < entropyBits; i++)
+        if (bits[i])
+            entropy[i / 8] |= (unsigned char)(1 << (7 - (i % 8)));
+
+    unsigned char checksum[SHA256_DIGEST_LENGTH];
+    SHA256(&entropy[0], entropy.size(), checksum);
+    for (size_t i = 0; i < checksumBits; i++)
+    {
+        if (bits[entropyBits + i] != GetBit(checksum, i))
+        {
+            errorOut = "mnemonic checksum failed";
+            return false;
+        }
+    }
+    return true;
+}
+
+bool BIP39MnemonicToSeed(const std::string& mnemonic,
+                         const std::string& passphrase,
+                         std::vector<unsigned char>& seedOut,
+                         std::string& errorOut)
+{
+    seedOut.assign(64, 0);
+    std::string normalized;
+    if (!BIP39ValidateMnemonic(mnemonic, normalized, errorOut))
+    {
+        seedOut.clear();
+        return false;
+    }
+
+    const std::string salt = "mnemonic" + passphrase;
+    if (!PKCS5_PBKDF2_HMAC(normalized.c_str(), normalized.size(),
+                           (const unsigned char*)salt.data(), salt.size(),
+                           2048, EVP_sha512(), 64, &seedOut[0]))
+    {
+        seedOut.clear();
+        errorOut = "PBKDF2-HMAC-SHA512 failed";
+        return false;
+    }
+    return true;
+}
+
+bool BIP32MasterFromSeed(const std::vector<unsigned char>& seed,
+                         BIP32PrivateNode& nodeOut,
+                         std::string& errorOut)
+{
+    nodeOut.privateKey.clear();
+    nodeOut.chainCode.clear();
+    errorOut.clear();
+    if (seed.size() < 16 || seed.size() > 64)
+    {
+        errorOut = "BIP32 seed must be between 128 and 512 bits";
+        return false;
+    }
+
+    unsigned char I[64];
+    static const unsigned char key[] = "Bitcoin seed";
+    if (!HmacSha512(key, sizeof(key) - 1, &seed[0], seed.size(), I))
+    {
+        errorOut = "HMAC-SHA512 failed";
+        return false;
+    }
+
+    nodeOut.privateKey.assign(I, I + 32);
+    nodeOut.chainCode.assign(I + 32, I + 64);
+    OPENSSL_cleanse(I, sizeof(I));
+
+    if (!IsValidPrivateKey(nodeOut.privateKey))
+    {
+        nodeOut.privateKey.clear();
+        nodeOut.chainCode.clear();
+        errorOut = "BIP32 master key is invalid";
+        return false;
+    }
+    return true;
+}
+
+bool BIP32DeriveHardenedChild(const BIP32PrivateNode& parent,
+                              unsigned int childIndex,
+                              BIP32PrivateNode& childOut,
+                              std::string& errorOut)
+{
+    childOut.privateKey.clear();
+    childOut.chainCode.clear();
+    errorOut.clear();
+    if (!IsValidPrivateKey(parent.privateKey) || parent.chainCode.size() != 32)
+    {
+        errorOut = "parent private key or chain code is invalid";
+        return false;
+    }
+    if (childIndex >= 0x80000000U)
+    {
+        errorOut = "child index must be non-hardened; hardening is applied here";
+        return false;
+    }
+
+    const unsigned int hardened = childIndex | 0x80000000U;
+    unsigned char data[37];
+    data[0] = 0x00;
+    memcpy(data + 1, &parent.privateKey[0], 32);
+    data[33] = (unsigned char)((hardened >> 24) & 0xff);
+    data[34] = (unsigned char)((hardened >> 16) & 0xff);
+    data[35] = (unsigned char)((hardened >> 8) & 0xff);
+    data[36] = (unsigned char)(hardened & 0xff);
+
+    unsigned char I[64];
+    if (!HmacSha512(&parent.chainCode[0], 32, data, sizeof(data), I))
+    {
+        OPENSSL_cleanse(data, sizeof(data));
+        errorOut = "HMAC-SHA512 failed";
+        return false;
+    }
+    OPENSSL_cleanse(data, sizeof(data));
+
+    std::vector<unsigned char> IL(I, I + 32);
+    childOut.chainCode.assign(I + 32, I + 64);
+    OPENSSL_cleanse(I, sizeof(I));
+
+    BIGNUM* bnIL = BN_bin2bn(&IL[0], 32, NULL);
+    BIGNUM* bnParent = BN_bin2bn(&parent.privateKey[0], 32, NULL);
+    BIGNUM* bnOrder = BN_new();
+    BIGNUM* bnChild = BN_new();
+    BN_CTX* ctx = BN_CTX_new();
+    EC_GROUP* group = EC_GROUP_new_by_curve_name(NID_secp256k1);
+
+    bool ok = false;
+    if (bnIL && bnParent && bnOrder && bnChild && ctx && group &&
+        EC_GROUP_get_order(group, bnOrder, NULL) &&
+        BN_cmp(bnIL, bnOrder) < 0 &&
+        BN_mod_add(bnChild, bnIL, bnParent, bnOrder, ctx) &&
+        !BN_is_zero(bnChild))
+    {
+        childOut.privateKey.assign(32, 0);
+        int n = BN_num_bytes(bnChild);
+        BN_bn2bin(bnChild, &childOut.privateKey[32 - n]);
+        ok = true;
+    }
+
+    BN_free(bnIL);
+    BN_free(bnParent);
+    BN_free(bnOrder);
+    BN_free(bnChild);
+    BN_CTX_free(ctx);
+    EC_GROUP_free(group);
+    OPENSSL_cleanse(&IL[0], IL.size());
+
+    if (!ok)
+    {
+        childOut.privateKey.clear();
+        childOut.chainCode.clear();
+        errorOut = "BIP32 child derivation produced an invalid key";
+        return false;
+    }
+    return true;
+}
+
+} // namespace bitflash
diff --git a/src/bip32.h b/src/bip32.h
new file mode 100644
index 0000000..a029444
--- /dev/null
+++ b/src/bip32.h
@@ -0,0 +1,53 @@
+// Copyright (c) 2026 Bitflash developers
+// Distributed under the MIT/X11 software license.
+//
+// BIP39/BIP32 primitives for deterministic wallet work.
+//
+// This module is deliberately independent from wallet.dat and GUI code. It is
+// the auditable foundation: mnemonic generation/validation, seed derivation,
+// and hardened private child derivation over secp256k1.
+
+#ifndef BITFLASH_BIP32_H
+#define BITFLASH_BIP32_H
+
+#include <string>
+#include <vector>
+
+namespace bitflash
+{
+
+struct BIP32PrivateNode
+{
+    std::vector<unsigned char> privateKey; // 32-byte scalar
+    std::vector<unsigned char> chainCode;  // 32 bytes
+};
+
+bool BIP39EntropyToMnemonic(const std::vector<unsigned char>& entropy,
+                            std::string& mnemonicOut,
+                            std::string& errorOut);
+
+bool BIP39GenerateMnemonic(std::string& mnemonicOut,
+                           std::string& errorOut,
+                           unsigned int entropyBytes = 16);
+
+bool BIP39ValidateMnemonic(const std::string& mnemonic,
+                           std::string& normalizedOut,
+                           std::string& errorOut);
+
+bool BIP39MnemonicToSeed(const std::string& mnemonic,
+                         const std::string& passphrase,
+                         std::vector<unsigned char>& seedOut,
+                         std::string& errorOut);
+
+bool BIP32MasterFromSeed(const std::vector<unsigned char>& seed,
+                         BIP32PrivateNode& nodeOut,
+                         std::string& errorOut);
+
+bool BIP32DeriveHardenedChild(const BIP32PrivateNode& parent,
+                              unsigned int childIndex,
+                              BIP32PrivateNode& childOut,
+                              std::string& errorOut);
+
+} // namespace bitflash
+
+#endif
diff --git a/src/bip39_english.h b/src/bip39_english.h
new file mode 100644
index 0000000..04b4ed2
--- /dev/null
+++ b/src/bip39_english.h
@@ -0,0 +1,2062 @@
+// BIP39 English Wordlist
+
+#ifndef BITFLASH_BIP39_ENGLISH_H
+#define BITFLASH_BIP39_ENGLISH_H
+
+namespace bitflash
+{
+
+static const char* BIP39_ENGLISH_WORDS[2048] = {
+    "abandon",
+    "ability",
+    "able",
+    "about",
+    "above",
+    "absent",
+    "absorb",
+    "abstract",
+    "absurd",
+    "abuse",
+    "access",
+    "accident",
+    "account",
+    "accuse",
+    "achieve",
+    "acid",
+    "acoustic",
+    "acquire",
+    "across",
+    "act",
+    "action",
+    "actor",
+    "actress",
+    "actual",
+    "adapt",
+    "add",
+    "addict",
+    "address",
+    "adjust",
+    "admit",
+    "adult",
+    "advance",
+    "advice",
+    "aerobic",
+    "affair",
+    "afford",
+    "afraid",
+    "again",
+    "age",
+    "agent",
+    "agree",
+    "ahead",
+    "aim",
+    "air",
+    "airport",
+    "aisle",
+    "alarm",
+    "album",
+    "alcohol",
+    "alert",
+    "alien",
+    "all",
+    "alley",
+    "allow",
+    "almost",
+    "alone",
+    "alpha",
+    "already",
+    "also",
+    "alter",
+    "always",
+    "amateur",
+    "amazing",
+    "among",
+    "amount",
+    "amused",
+    "analyst",
+    "anchor",
+    "ancient",
+    "anger",
+    "angle",
+    "angry",
+    "animal",
+    "ankle",
+    "announce",
+    "annual",
+    "another",
+    "answer",
+    "antenna",
+    "antique",
+    "anxiety",
+    "any",
+    "apart",
+    "apology",
+    "appear",
+    "apple",
+    "approve",
+    "april",
+    "arch",
+    "arctic",
+    "area",
+    "arena",
+    "argue",
+    "arm",
+    "armed",
+    "armor",
+    "army",
+    "around",
+    "arrange",
+    "arrest",
+    "arrive",
+    "arrow",
+    "art",
+    "artefact",
+    "artist",
+    "artwork",
+    "ask",
+    "aspect",
+    "assault",
+    "asset",
+    "assist",
+    "assume",
+    "asthma",
+    "athlete",
+    "atom",
+    "attack",
+    "attend",
+    "attitude",
+    "attract",
+    "auction",
+    "audit",
+    "august",
+    "aunt",
+    "author",
+    "auto",
+    "autumn",
+    "average",
+    "avocado",
+    "avoid",
+    "awake",
+    "aware",
+    "away",
+    "awesome",
+    "awful",
+    "awkward",
+    "axis",
+    "baby",
+    "bachelor",
+    "bacon",
+    "badge",
+    "bag",
+    "balance",
+    "balcony",
+    "ball",
+    "bamboo",
+    "banana",
+    "banner",
+    "bar",
+    "barely",
+    "bargain",
+    "barrel",
+    "base",
+    "basic",
+    "basket",
+    "battle",
+    "beach",
+    "bean",
+    "beauty",
+    "because",
+    "become",
+    "beef",
+    "before",
+    "begin",
+    "behave",
+    "behind",
+    "believe",
+    "below",
+    "belt",
+    "bench",
+    "benefit",
+    "best",
+    "betray",
+    "better",
+    "between",
+    "beyond",
+    "bicycle",
+    "bid",
+    "bike",
+    "bind",
+    "biology",
+    "bird",
+    "birth",
+    "bitter",
+    "black",
+    "blade",
+    "blame",
+    "blanket",
+    "blast",
+    "bleak",
+    "bless",
+    "blind",
+    "blood",
+    "blossom",
+    "blouse",
+    "blue",
+    "blur",
+    "blush",
+    "board",
+    "boat",
+    "body",
+    "boil",
+    "bomb",
+    "bone",
+    "bonus",
+    "book",
+    "boost",
+    "border",
+    "boring",
+    "borrow",
+    "boss",
+    "bottom",
+    "bounce",
+    "box",
+    "boy",
+    "bracket",
+    "brain",
+    "brand",
+    "brass",
+    "brave",
+    "bread",
+    "breeze",
+    "brick",
+    "bridge",
+    "brief",
+    "bright",
+    "bring",
+    "brisk",
+    "broccoli",
+    "broken",
+    "bronze",
+    "broom",
+    "brother",
+    "brown",
+    "brush",
+    "bubble",
+    "buddy",
+    "budget",
+    "buffalo",
+    "build",
+    "bulb",
+    "bulk",
+    "bullet",
+    "bundle",
+    "bunker",
+    "burden",
+    "burger",
+    "burst",
+    "bus",
+    "business",
+    "busy",
+    "butter",
+    "buyer",
+    "buzz",
+    "cabbage",
+    "cabin",
+    "cable",
+    "cactus",
+    "cage",
+    "cake",
+    "call",
+    "calm",
+    "camera",
+    "camp",
+    "can",
+    "canal",
+    "cancel",
+    "candy",
+    "cannon",
+    "canoe",
+    "canvas",
+    "canyon",
+    "capable",
+    "capital",
+    "captain",
+    "car",
+    "carbon",
+    "card",
+    "cargo",
+    "carpet",
+    "carry",
+    "cart",
+    "case",
+    "cash",
+    "casino",
+    "castle",
+    "casual",
+    "cat",
+    "catalog",
+    "catch",
+    "category",
+    "cattle",
+    "caught",
+    "cause",
+    "caution",
+    "cave",
+    "ceiling",
+    "celery",
+    "cement",
+    "census",
+    "century",
+    "cereal",
+    "certain",
+    "chair",
+    "chalk",
+    "champion",
+    "change",
+    "chaos",
+    "chapter",
+    "charge",
+    "chase",
+    "chat",
+    "cheap",
+    "check",
+    "cheese",
+    "chef",
+    "cherry",
+    "chest",
+    "chicken",
+    "chief",
+    "child",
+    "chimney",
+    "choice",
+    "choose",
+    "chronic",
+    "chuckle",
+    "chunk",
+    "churn",
+    "cigar",
+    "cinnamon",
+    "circle",
+    "citizen",
+    "city",
+    "civil",
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+    "rail",
+    "rain",
+    "raise",
+    "rally",
+    "ramp",
+    "ranch",
+    "random",
+    "range",
+    "rapid",
+    "rare",
+    "rate",
+    "rather",
+    "raven",
+    "raw",
+    "razor",
+    "ready",
+    "real",
+    "reason",
+    "rebel",
+    "rebuild",
+    "recall",
+    "receive",
+    "recipe",
+    "record",
+    "recycle",
+    "reduce",
+    "reflect",
+    "reform",
+    "refuse",
+    "region",
+    "regret",
+    "regular",
+    "reject",
+    "relax",
+    "release",
+    "relief",
+    "rely",
+    "remain",
+    "remember",
+    "remind",
+    "remove",
+    "render",
+    "renew",
+    "rent",
+    "reopen",
+    "repair",
+    "repeat",
+    "replace",
+    "report",
+    "require",
+    "rescue",
+    "resemble",
+    "resist",
+    "resource",
+    "response",
+    "result",
+    "retire",
+    "retreat",
+    "return",
+    "reunion",
+    "reveal",
+    "review",
+    "reward",
+    "rhythm",
+    "rib",
+    "ribbon",
+    "rice",
+    "rich",
+    "ride",
+    "ridge",
+    "rifle",
+    "right",
+    "rigid",
+    "ring",
+    "riot",
+    "ripple",
+    "risk",
+    "ritual",
+    "rival",
+    "river",
+    "road",
+    "roast",
+    "robot",
+    "robust",
+    "rocket",
+    "romance",
+    "roof",
+    "rookie",
+    "room",
+    "rose",
+    "rotate",
+    "rough",
+    "round",
+    "route",
+    "royal",
+    "rubber",
+    "rude",
+    "rug",
+    "rule",
+    "run",
+    "runway",
+    "rural",
+    "sad",
+    "saddle",
+    "sadness",
+    "safe",
+    "sail",
+    "salad",
+    "salmon",
+    "salon",
+    "salt",
+    "salute",
+    "same",
+    "sample",
+    "sand",
+    "satisfy",
+    "satoshi",
+    "sauce",
+    "sausage",
+    "save",
+    "say",
+    "scale",
+    "scan",
+    "scare",
+    "scatter",
+    "scene",
+    "scheme",
+    "school",
+    "science",
+    "scissors",
+    "scorpion",
+    "scout",
+    "scrap",
+    "screen",
+    "script",
+    "scrub",
+    "sea",
+    "search",
+    "season",
+    "seat",
+    "second",
+    "secret",
+    "section",
+    "security",
+    "seed",
+    "seek",
+    "segment",
+    "select",
+    "sell",
+    "seminar",
+    "senior",
+    "sense",
+    "sentence",
+    "series",
+    "service",
+    "session",
+    "settle",
+    "setup",
+    "seven",
+    "shadow",
+    "shaft",
+    "shallow",
+    "share",
+    "shed",
+    "shell",
+    "sheriff",
+    "shield",
+    "shift",
+    "shine",
+    "ship",
+    "shiver",
+    "shock",
+    "shoe",
+    "shoot",
+    "shop",
+    "short",
+    "shoulder",
+    "shove",
+    "shrimp",
+    "shrug",
+    "shuffle",
+    "shy",
+    "sibling",
+    "sick",
+    "side",
+    "siege",
+    "sight",
+    "sign",
+    "silent",
+    "silk",
+    "silly",
+    "silver",
+    "similar",
+    "simple",
+    "since",
+    "sing",
+    "siren",
+    "sister",
+    "situate",
+    "six",
+    "size",
+    "skate",
+    "sketch",
+    "ski",
+    "skill",
+    "skin",
+    "skirt",
+    "skull",
+    "slab",
+    "slam",
+    "sleep",
+    "slender",
+    "slice",
+    "slide",
+    "slight",
+    "slim",
+    "slogan",
+    "slot",
+    "slow",
+    "slush",
+    "small",
+    "smart",
+    "smile",
+    "smoke",
+    "smooth",
+    "snack",
+    "snake",
+    "snap",
+    "sniff",
+    "snow",
+    "soap",
+    "soccer",
+    "social",
+    "sock",
+    "soda",
+    "soft",
+    "solar",
+    "soldier",
+    "solid",
+    "solution",
+    "solve",
+    "someone",
+    "song",
+    "soon",
+    "sorry",
+    "sort",
+    "soul",
+    "sound",
+    "soup",
+    "source",
+    "south",
+    "space",
+    "spare",
+    "spatial",
+    "spawn",
+    "speak",
+    "special",
+    "speed",
+    "spell",
+    "spend",
+    "sphere",
+    "spice",
+    "spider",
+    "spike",
+    "spin",
+    "spirit",
+    "split",
+    "spoil",
+    "sponsor",
+    "spoon",
+    "sport",
+    "spot",
+    "spray",
+    "spread",
+    "spring",
+    "spy",
+    "square",
+    "squeeze",
+    "squirrel",
+    "stable",
+    "stadium",
+    "staff",
+    "stage",
+    "stairs",
+    "stamp",
+    "stand",
+    "start",
+    "state",
+    "stay",
+    "steak",
+    "steel",
+    "stem",
+    "step",
+    "stereo",
+    "stick",
+    "still",
+    "sting",
+    "stock",
+    "stomach",
+    "stone",
+    "stool",
+    "story",
+    "stove",
+    "strategy",
+    "street",
+    "strike",
+    "strong",
+    "struggle",
+    "student",
+    "stuff",
+    "stumble",
+    "style",
+    "subject",
+    "submit",
+    "subway",
+    "success",
+    "such",
+    "sudden",
+    "suffer",
+    "sugar",
+    "suggest",
+    "suit",
+    "summer",
+    "sun",
+    "sunny",
+    "sunset",
+    "super",
+    "supply",
+    "supreme",
+    "sure",
+    "surface",
+    "surge",
+    "surprise",
+    "surround",
+    "survey",
+    "suspect",
+    "sustain",
+    "swallow",
+    "swamp",
+    "swap",
+    "swarm",
+    "swear",
+    "sweet",
+    "swift",
+    "swim",
+    "swing",
+    "switch",
+    "sword",
+    "symbol",
+    "symptom",
+    "syrup",
+    "system",
+    "table",
+    "tackle",
+    "tag",
+    "tail",
+    "talent",
+    "talk",
+    "tank",
+    "tape",
+    "target",
+    "task",
+    "taste",
+    "tattoo",
+    "taxi",
+    "teach",
+    "team",
+    "tell",
+    "ten",
+    "tenant",
+    "tennis",
+    "tent",
+    "term",
+    "test",
+    "text",
+    "thank",
+    "that",
+    "theme",
+    "then",
+    "theory",
+    "there",
+    "they",
+    "thing",
+    "this",
+    "thought",
+    "three",
+    "thrive",
+    "throw",
+    "thumb",
+    "thunder",
+    "ticket",
+    "tide",
+    "tiger",
+    "tilt",
+    "timber",
+    "time",
+    "tiny",
+    "tip",
+    "tired",
+    "tissue",
+    "title",
+    "toast",
+    "tobacco",
+    "today",
+    "toddler",
+    "toe",
+    "together",
+    "toilet",
+    "token",
+    "tomato",
+    "tomorrow",
+    "tone",
+    "tongue",
+    "tonight",
+    "tool",
+    "tooth",
+    "top",
+    "topic",
+    "topple",
+    "torch",
+    "tornado",
+    "tortoise",
+    "toss",
+    "total",
+    "tourist",
+    "toward",
+    "tower",
+    "town",
+    "toy",
+    "track",
+    "trade",
+    "traffic",
+    "tragic",
+    "train",
+    "transfer",
+    "trap",
+    "trash",
+    "travel",
+    "tray",
+    "treat",
+    "tree",
+    "trend",
+    "trial",
+    "tribe",
+    "trick",
+    "trigger",
+    "trim",
+    "trip",
+    "trophy",
+    "trouble",
+    "truck",
+    "true",
+    "truly",
+    "trumpet",
+    "trust",
+    "truth",
+    "try",
+    "tube",
+    "tuition",
+    "tumble",
+    "tuna",
+    "tunnel",
+    "turkey",
+    "turn",
+    "turtle",
+    "twelve",
+    "twenty",
+    "twice",
+    "twin",
+    "twist",
+    "two",
+    "type",
+    "typical",
+    "ugly",
+    "umbrella",
+    "unable",
+    "unaware",
+    "uncle",
+    "uncover",
+    "under",
+    "undo",
+    "unfair",
+    "unfold",
+    "unhappy",
+    "uniform",
+    "unique",
+    "unit",
+    "universe",
+    "unknown",
+    "unlock",
+    "until",
+    "unusual",
+    "unveil",
+    "update",
+    "upgrade",
+    "uphold",
+    "upon",
+    "upper",
+    "upset",
+    "urban",
+    "urge",
+    "usage",
+    "use",
+    "used",
+    "useful",
+    "useless",
+    "usual",
+    "utility",
+    "vacant",
+    "vacuum",
+    "vague",
+    "valid",
+    "valley",
+    "valve",
+    "van",
+    "vanish",
+    "vapor",
+    "various",
+    "vast",
+    "vault",
+    "vehicle",
+    "velvet",
+    "vendor",
+    "venture",
+    "venue",
+    "verb",
+    "verify",
+    "version",
+    "very",
+    "vessel",
+    "veteran",
+    "viable",
+    "vibrant",
+    "vicious",
+    "victory",
+    "video",
+    "view",
+    "village",
+    "vintage",
+    "violin",
+    "virtual",
+    "virus",
+    "visa",
+    "visit",
+    "visual",
+    "vital",
+    "vivid",
+    "vocal",
+    "voice",
+    "void",
+    "volcano",
+    "volume",
+    "vote",
+    "voyage",
+    "wage",
+    "wagon",
+    "wait",
+    "walk",
+    "wall",
+    "walnut",
+    "want",
+    "warfare",
+    "warm",
+    "warrior",
+    "wash",
+    "wasp",
+    "waste",
+    "water",
+    "wave",
+    "way",
+    "wealth",
+    "weapon",
+    "wear",
+    "weasel",
+    "weather",
+    "web",
+    "wedding",
+    "weekend",
+    "weird",
+    "welcome",
+    "west",
+    "wet",
+    "whale",
+    "what",
+    "wheat",
+    "wheel",
+    "when",
+    "where",
+    "whip",
+    "whisper",
+    "wide",
+    "width",
+    "wife",
+    "wild",
+    "will",
+    "win",
+    "window",
+    "wine",
+    "wing",
+    "wink",
+    "winner",
+    "winter",
+    "wire",
+    "wisdom",
+    "wise",
+    "wish",
+    "witness",
+    "wolf",
+    "woman",
+    "wonder",
+    "wood",
+    "wool",
+    "word",
+    "work",
+    "world",
+    "worry",
+    "worth",
+    "wrap",
+    "wreck",
+    "wrestle",
+    "wrist",
+    "write",
+    "wrong",
+    "yard",
+    "year",
+    "yellow",
+    "you",
+    "young",
+    "youth",
+    "zebra",
+    "zero",
+    "zone",
+    "zoo",
+};
+
+} // namespace bitflash
+
+#endif
diff --git a/src/makefile.mingw b/src/makefile.mingw
index ae533ef..e4dee59 100644
--- a/src/makefile.mingw
+++ b/src/makefile.mingw
@@ -92,4 +92,11 @@ bitflash.exe: $(IMGUI_OBJS) $(NODE_OBJS) $(GUI_OBJS)
         @echo "Built: bitflash.exe"
 
 clean:
-        rm -rf obj bitflash.exe
+        rm -rf obj bitflash.exe test_bip32.exe
+
+test_bip32.exe: test_bip32.cpp bip32.cpp bip32.h bip39_english.h
+        $(CXX) $(CXXFLAGS) -o $@ test_bip32.cpp bip32.cpp -lssl -lcrypto -lcrypt32
+        @echo "Built: test_bip32.exe"
+
+tests: test_bip32.exe
+        ./test_bip32.exe
diff --git a/src/test_bip32.cpp b/src/test_bip32.cpp
new file mode 100644
index 0000000..610a651
--- /dev/null
+++ b/src/test_bip32.cpp
@@ -0,0 +1,130 @@
+// Standalone tests for BIP39/BIP32 primitives.
+//
+// Build:
+//   g++ -std=gnu++14 test_bip32.cpp bip32.cpp -lssl -lcrypto -o test_bip32
+
+#include "bip32.h"
+
+#include <cstdio>
+#include <cstring>
+#include <string>
+#include <vector>
+
+using namespace bitflash;
+
+static int g_fail = 0;
+
+#define CHECK(cond, name) do { \
+    if (cond) { printf("  ok   %s\n", name); } \
+    else      { printf("  FAIL %s\n", name); g_fail++; } \
+} while (0)
+
+static int HexDigit(char c)
+{
+    if (c >= '0' && c <= '9') return c - '0';
+    if (c >= 'a' && c <= 'f') return c - 'a' + 10;
+    if (c >= 'A' && c <= 'F') return c - 'A' + 10;
+    return -1;
+}
+
+static std::vector<unsigned char> FromHex(const std::string& s)
+{
+    std::vector<unsigned char> out;
+    if (s.size() % 2 != 0)
+        return out;
+    out.reserve(s.size() / 2);
+    for (size_t i = 0; i < s.size(); i += 2)
+    {
+        int hi = HexDigit(s[i]);
+        int lo = HexDigit(s[i + 1]);
+        if (hi < 0 || lo < 0)
+            return std::vector<unsigned char>();
+        out.push_back((unsigned char)((hi << 4) | lo));
+    }
+    return out;
+}
+
+static std::string ToHex(const std::vector<unsigned char>& v)
+{
+    static const char* hex = "0123456789abcdef";
+    std::string out;
+    out.reserve(v.size() * 2);
+    for (unsigned char c : v)
+    {
+        out.push_back(hex[c >> 4]);
+        out.push_back(hex[c & 0x0f]);
+    }
+    return out;
+}
+
+int main()
+{
+    std::string err;
+
+    printf("bip39_entropy_to_mnemonic\n");
+    {
+        std::vector<unsigned char> entropy(16, 0);
+        std::string mnemonic;
+        CHECK(BIP39EntropyToMnemonic(entropy, mnemonic, err), "zero entropy encodes");
+        CHECK(mnemonic ==
+              "abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon about",
+              "matches BIP39 vector");
+    }
+
+    printf("bip39_validation\n");
+    {
+        std::string normalized;
+        CHECK(BIP39ValidateMnemonic(
+              "  Abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon about  ",
+              normalized, err),
+              "valid phrase normalizes");
+        CHECK(normalized ==
+              "abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon about",
+              "normalized text matches");
+        CHECK(!BIP39ValidateMnemonic(
+              "abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon",
+              normalized, err),
+              "bad checksum rejected");
+    }
+
+    printf("bip39_seed\n");
+    {
+        std::vector<unsigned char> seed;
+        const std::string mnemonic =
+            "abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon about";
+        CHECK(BIP39MnemonicToSeed(mnemonic, "TREZOR", seed, err), "mnemonic derives seed");
+        CHECK(ToHex(seed) ==
+              "c55257c360c07c72029aebc1b53c05ed0362ada38ead3e3e9efa3708e5349553"
+              "1f09a6987599d18264c1e1c92f2cf141630c7a3c4ab7c81b2f001698e7463b04",
+              "matches BIP39 seed vector");
+    }
+
+    printf("bip32_master\n");
+    {
+        std::vector<unsigned char> seed = FromHex("000102030405060708090a0b0c0d0e0f");
+        BIP32PrivateNode master;
+        CHECK(BIP32MasterFromSeed(seed, master, err), "master key derives");
+        CHECK(ToHex(master.privateKey) ==
+              "e8f32e723decf4051aefac8e2c93c9c5b214313817cdb01a1494b917c8436b35",
+              "matches BIP32 master private key");
+        CHECK(ToHex(master.chainCode) ==
+              "873dff81c02f525623fd1fe5167eac3a55a049de3d314bb42ee227ffed37d508",
+              "matches BIP32 master chain code");
+
+        BIP32PrivateNode childA, childB;
+        CHECK(BIP32DeriveHardenedChild(master, 0, childA, err), "hardened child derives");
+        CHECK(BIP32DeriveHardenedChild(master, 0, childB, err), "hardened child re-derives");
+        CHECK(childA.privateKey == childB.privateKey &&
+              childA.chainCode == childB.chainCode,
+              "same child path is deterministic");
+        CHECK(childA.privateKey != master.privateKey &&
+              childA.chainCode != master.chainCode,
+              "child differs from parent");
+        CHECK(!BIP32DeriveHardenedChild(master, 0x80000000U, childA, err),
+              "pre-hardened index rejected");
+    }
+
+    printf("\n%s (%d failures)\n",
+           g_fail == 0 ? "ALL TESTS PASSED" : "TESTS FAILED", g_fail);
+    return g_fail == 0 ? 0 : 1;
+}