Unit tests for the crypto_tr_* taproot helpers

diff --git a/unit-tests/libs/speculos_bridge.c b/unit-tests/libs/speculos_bridge.c
index 0110bed..3112f03 100644
--- a/unit-tests/libs/speculos_bridge.c
+++ b/unit-tests/libs/speculos_bridge.c
@@ -240,31 +240,50 @@ cx_err_t cx_ripemd160_hash_iovec(const cx_iovec_t_local *iovec,
             name);                                                        \
     abort()
 
-cx_err_t cx_hash_no_throw(void *hash,
+extern unsigned long sys_cx_hash(cx_hash_t *hash,
+                                 int mode,
+                                 const uint8_t *in,
+                                 size_t len,
+                                 uint8_t *out,
+                                 size_t out_len);
+
+cx_err_t cx_hash_no_throw(cx_hash_t *hash,
                           int mode,
                           const unsigned char *in,
                           size_t len,
                           unsigned char *out,
                           size_t out_len) {
-    (void) hash;
-    (void) mode;
-    (void) in;
-    (void) len;
-    (void) out;
-    (void) out_len;
-    STUB_ABORT("cx_hash_no_throw");
+    /* speculos's sys_cx_hash returns digest_len on CX_LAST success and 0
+     * otherwise; the SDK function returns CX_OK on success regardless.
+     * speculos THROWs on any error (mapped to abort by the bridge), so
+     * if we get here at all, treat it as success. */
+    (void) sys_cx_hash(hash, mode, in, len, out, out_len);
+    return 0; /* CX_OK */
 }
 
-cx_err_t cx_sha256_init_no_throw(void *hash) {
-    (void) hash;
-    STUB_ABORT("cx_sha256_init_no_throw");
+/* cx_sha256_init is exposed directly by speculos (no sys_ prefix). */
+extern int cx_sha256_init(cx_sha256_t *hash);
+
+cx_err_t cx_sha256_init_no_throw(cx_sha256_t *hash) {
+    /* Per the SDK header, this function always returns CX_OK. */
+    cx_sha256_init(hash);
+    return 0;
 }
 
-cx_err_t cx_sha256_hash_iovec(const void *iovec, size_t iovec_count, uint8_t *out) {
-    (void) iovec;
-    (void) iovec_count;
-    (void) out;
-    STUB_ABORT("cx_sha256_hash_iovec");
+/* Reuses cx_iovec_t_local from the RIPEMD-160 forwarder above; same
+ * layout as the SDK / mock cx_iovec_t. */
+cx_err_t cx_sha256_hash_iovec(const cx_iovec_t_local *iovec, size_t iovec_count,
+                              uint8_t *out) {
+    cx_sha256_t ctx;
+    cx_sha256_init(&ctx);
+    for (size_t i = 0; i < iovec_count; i++) {
+        if (iovec[i].iov_len > 0) {
+            sys_cx_hash(&ctx.header, 0, iovec[i].iov_base, iovec[i].iov_len,
+                        NULL, 0);
+        }
+    }
+    sys_cx_hash(&ctx.header, CX_LAST, NULL, 0, out, 32);
+    return 0;
 }
 
 cx_err_t cx_math_addm_no_throw(uint8_t *r,
diff --git a/unit-tests/test_crypto.c b/unit-tests/test_crypto.c
index 93b5573..54dfc7c 100644
--- a/unit-tests/test_crypto.c
+++ b/unit-tests/test_crypto.c
@@ -586,6 +586,269 @@ static void test_crypto_ecdsa_sign_sha256_hash_with_key_no_optional_outputs(
     assert_true(sig_len <= MAX_DER_SIG_LEN);
 }
 
+/* ---------------------------------------------------------------- */
+/* crypto_tr_* (BIP-340/BIP-341 helpers)                            */
+/*                                                                  */
+/* Test vectors verified against test_utils/taproot.py.             */
+/*                                                                  */
+/* The streaming-init helpers take a cx_sha256_t*. The mock_includes */
+/* layout of that struct is a few bytes smaller than the real SDK   */
+/* one used by app_crypto, so the tests allocate an oversized       */
+/* aligned buffer and cast through it.                              */
+/* ---------------------------------------------------------------- */
+
+#define CX_SHA256_T_STORAGE_BYTES 128
+
+static void test_crypto_tr_tagged_hash_init_custom_tag(void **state) {
+    (void) state;
+    /* tagged_hash("TestTag", "hello" || "world") */
+    static const uint8_t tag[] = "TestTag";
+    static const uint8_t expected[32] = {
+        0x81, 0x13, 0xad, 0xac, 0x16, 0x04, 0xa6, 0xd0, 0x74, 0x0c,
+        0x15, 0x9f, 0xc4, 0xcf, 0x2b, 0xbe, 0x54, 0xc8, 0x10, 0x34,
+        0x19, 0x35, 0x10, 0x54, 0xbe, 0x4e, 0x77, 0xe4, 0xaf, 0x80,
+        0x20, 0xd9,
+    };
+
+    uint8_t ctx_storage[CX_SHA256_T_STORAGE_BYTES] __attribute__((aligned(8)));
+    cx_sha256_t *ctx = (cx_sha256_t *) ctx_storage;
+    crypto_tr_tagged_hash_init(ctx, tag, sizeof(tag) - 1);
+    assert_int_equal(crypto_hash_update(&ctx->header, "hello", 5), 0);
+    assert_int_equal(crypto_hash_update(&ctx->header, "world", 5), 0);
+    uint8_t out[32];
+    assert_int_equal(crypto_hash_digest(&ctx->header, out, sizeof(out)), 0);
+    assert_memory_equal(out, expected, 32);
+}
+
+static void test_crypto_tr_tapleaf_hash_init(void **state) {
+    (void) state;
+    /* tagged_hash("TapLeaf", "abc") */
+    static const uint8_t expected[32] = {
+        0x83, 0xa5, 0x63, 0x08, 0xa9, 0xc5, 0x6f, 0x46, 0x7e, 0x8d,
+        0xf2, 0x93, 0xda, 0x5a, 0xe5, 0xfd, 0xbc, 0x85, 0xb8, 0x71,
+        0x95, 0x2a, 0x83, 0xc4, 0xbf, 0x05, 0x75, 0xee, 0x94, 0x8e,
+        0xc2, 0x30,
+    };
+
+    uint8_t ctx_storage[CX_SHA256_T_STORAGE_BYTES] __attribute__((aligned(8)));
+    cx_sha256_t *ctx = (cx_sha256_t *) ctx_storage;
+    crypto_tr_tapleaf_hash_init(ctx);
+    assert_int_equal(crypto_hash_update(&ctx->header, "abc", 3), 0);
+    uint8_t out[32];
+    assert_int_equal(crypto_hash_digest(&ctx->header, out, sizeof(out)), 0);
+    assert_memory_equal(out, expected, 32);
+}
+
+static void test_crypto_tr_lift_x_secp256k1_generator(void **state) {
+    (void) state;
+    /* lift_x of the secp256k1 generator's x-only coordinate produces
+     * the (even-y) generator point itself, in uncompressed form. */
+    static const uint8_t Gx[32] = {
+        0x79, 0xbe, 0x66, 0x7e, 0xf9, 0xdc, 0xbb, 0xac, 0x55, 0xa0, 0x62,
+        0x95, 0xce, 0x87, 0x0b, 0x07, 0x02, 0x9b, 0xfc, 0xdb, 0x2d, 0xce,
+        0x28, 0xd9, 0x59, 0xf2, 0x81, 0x5b, 0x16, 0xf8, 0x17, 0x98,
+    };
+    static const uint8_t expected[65] = {
+        0x04,
+        0x79, 0xbe, 0x66, 0x7e, 0xf9, 0xdc, 0xbb, 0xac, 0x55, 0xa0, 0x62, 0x95,
+        0xce, 0x87, 0x0b, 0x07, 0x02, 0x9b, 0xfc, 0xdb, 0x2d, 0xce, 0x28, 0xd9,
+        0x59, 0xf2, 0x81, 0x5b, 0x16, 0xf8, 0x17, 0x98,
+        0x48, 0x3a, 0xda, 0x77, 0x26, 0xa3, 0xc4, 0x65, 0x5d, 0xa4, 0xfb, 0xfc,
+        0x0e, 0x11, 0x08, 0xa8, 0xfd, 0x17, 0xb4, 0x48, 0xa6, 0x85, 0x54, 0x19,
+        0x9c, 0x47, 0xd0, 0x8f, 0xfb, 0x10, 0xd4, 0xb8,
+    };
+    uint8_t out[65];
+    assert_int_equal(crypto_tr_lift_x(Gx, out), 0);
+    assert_memory_equal(out, expected, 65);
+}
+
+static void test_crypto_tr_lift_x_not_on_curve(void **state) {
+    (void) state;
+    /* x = 5: with secp256k1's b=7, y^2 = 5^3 + 7 = 132 is not a
+     * quadratic residue mod p, so no point with this x exists. */
+    static const uint8_t x_invalid[32] = {0};
+    uint8_t x_with_5[32] = {0};
+    x_with_5[31] = 5;
+    uint8_t out[65];
+    assert_int_equal(crypto_tr_lift_x(x_with_5, out), -1);
+    /* Sanity: zero-init not_on_curve too */
+    (void) x_invalid;
+}
+
+static void test_crypto_tr_tagged_hash_single_data(void **state) {
+    (void) state;
+    /* tagged_hash("TapTweak", G_x) */
+    static const uint8_t tag[] = "TapTweak";
+    static const uint8_t data[32] = {
+        0x79, 0xbe, 0x66, 0x7e, 0xf9, 0xdc, 0xbb, 0xac, 0x55, 0xa0, 0x62,
+        0x95, 0xce, 0x87, 0x0b, 0x07, 0x02, 0x9b, 0xfc, 0xdb, 0x2d, 0xce,
+        0x28, 0xd9, 0x59, 0xf2, 0x81, 0x5b, 0x16, 0xf8, 0x17, 0x98,
+    };
+    static const uint8_t expected[32] = {
+        0x3c, 0xf5, 0x21, 0x6d, 0x47, 0x6a, 0x5e, 0x63, 0x7b, 0xf0,
+        0xda, 0x67, 0x4e, 0x50, 0xdd, 0xf5, 0x5c, 0x40, 0x32, 0x70,
+        0xdd, 0x36, 0x49, 0x4d, 0xfc, 0xca, 0x43, 0x81, 0x32, 0xfa,
+        0x30, 0xe7,
+    };
+    uint8_t out[32];
+    crypto_tr_tagged_hash(tag, sizeof(tag) - 1, data, sizeof(data), NULL, 0,
+                          out);
+    assert_memory_equal(out, expected, 32);
+}
+
+static void test_crypto_tr_tagged_hash_two_parts(void **state) {
+    (void) state;
+    /* tagged_hash("TestTag", "hello" || "world") — same expected as the
+     * streaming variant above; the two ways of feeding data must agree. */
+    static const uint8_t tag[] = "TestTag";
+    static const uint8_t expected[32] = {
+        0x81, 0x13, 0xad, 0xac, 0x16, 0x04, 0xa6, 0xd0, 0x74, 0x0c,
+        0x15, 0x9f, 0xc4, 0xcf, 0x2b, 0xbe, 0x54, 0xc8, 0x10, 0x34,
+        0x19, 0x35, 0x10, 0x54, 0xbe, 0x4e, 0x77, 0xe4, 0xaf, 0x80,
+        0x20, 0xd9,
+    };
+    uint8_t out[32];
+    crypto_tr_tagged_hash(tag, sizeof(tag) - 1,
+                          (const uint8_t *) "hello", 5,
+                          (const uint8_t *) "world", 5, out);
+    assert_memory_equal(out, expected, 32);
+}
+
+static void test_crypto_tr_combine_taptree_hashes_sorted(void **state) {
+    (void) state;
+    static const uint8_t left[32] = {
+        0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa,
+        0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa,
+        0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa,
+    };
+    static const uint8_t right[32] = {
+        0xbb, 0xbb, 0xbb, 0xbb, 0xbb, 0xbb, 0xbb, 0xbb, 0xbb, 0xbb, 0xbb,
+        0xbb, 0xbb, 0xbb, 0xbb, 0xbb, 0xbb, 0xbb, 0xbb, 0xbb, 0xbb, 0xbb,
+        0xbb, 0xbb, 0xbb, 0xbb, 0xbb, 0xbb, 0xbb, 0xbb, 0xbb, 0xbb,
+    };
+    static const uint8_t expected[32] = {
+        0x9e, 0xbc, 0xd2, 0x4c, 0xc8, 0xce, 0x07, 0x23, 0x30, 0x06,
+        0x0f, 0xa7, 0x64, 0xfc, 0x18, 0xf5, 0x17, 0xb3, 0x85, 0x6b,
+        0x26, 0x41, 0x15, 0x73, 0x9c, 0xb2, 0xbb, 0xf3, 0xa0, 0x55,
+        0x14, 0x2b,
+    };
+    uint8_t out[32];
+    crypto_tr_combine_taptree_hashes(left, right, out);
+    assert_memory_equal(out, expected, 32);
+}
+
+static void test_crypto_tr_combine_taptree_hashes_reversed(void **state) {
+    (void) state;
+    /* The function must sort by lexicographic order, so swapping left
+     * and right should yield the same combined hash. */
+    static const uint8_t a[32] = {
+        0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa,
+        0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa,
+        0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa,
+    };
+    static const uint8_t b[32] = {
+        0xbb, 0xbb, 0xbb, 0xbb, 0xbb, 0xbb, 0xbb, 0xbb, 0xbb, 0xbb, 0xbb,
+        0xbb, 0xbb, 0xbb, 0xbb, 0xbb, 0xbb, 0xbb, 0xbb, 0xbb, 0xbb, 0xbb,
+        0xbb, 0xbb, 0xbb, 0xbb, 0xbb, 0xbb, 0xbb, 0xbb, 0xbb, 0xbb,
+    };
+    uint8_t out_ab[32], out_ba[32];
+    crypto_tr_combine_taptree_hashes(a, b, out_ab);
+    crypto_tr_combine_taptree_hashes(b, a, out_ba);
+    assert_memory_equal(out_ab, out_ba, 32);
+}
+
+static void test_crypto_tr_tweak_pubkey_empty_h(void **state) {
+    (void) state;
+    /* taproot_tweak_pubkey(G_x, "") */
+    static const uint8_t pubkey[32] = {
+        0x79, 0xbe, 0x66, 0x7e, 0xf9, 0xdc, 0xbb, 0xac, 0x55, 0xa0, 0x62,
+        0x95, 0xce, 0x87, 0x0b, 0x07, 0x02, 0x9b, 0xfc, 0xdb, 0x2d, 0xce,
+        0x28, 0xd9, 0x59, 0xf2, 0x81, 0x5b, 0x16, 0xf8, 0x17, 0x98,
+    };
+    static const uint8_t expected[32] = {
+        0xda, 0x47, 0x10, 0x96, 0x4f, 0x78, 0x52, 0x69, 0x5d, 0xe2,
+        0xda, 0x02, 0x52, 0x90, 0xe2, 0x4a, 0xf6, 0xd8, 0xc2, 0x81,
+        0xde, 0x5a, 0x0b, 0x90, 0x2b, 0x71, 0x35, 0xfd, 0x9f, 0xd7,
+        0x4d, 0x21,
+    };
+    uint8_t out[32];
+    uint8_t y_parity = 0;
+    assert_int_equal(crypto_tr_tweak_pubkey(pubkey, NULL, 0, &y_parity, out), 0);
+    assert_int_equal(y_parity, 1);
+    assert_memory_equal(out, expected, 32);
+}
+
+static void test_crypto_tr_tweak_pubkey_with_h(void **state) {
+    (void) state;
+    /* taproot_tweak_pubkey(G_x, h) for a non-empty 32-byte h */
+    static const uint8_t pubkey[32] = {
+        0x79, 0xbe, 0x66, 0x7e, 0xf9, 0xdc, 0xbb, 0xac, 0x55, 0xa0, 0x62,
+        0x95, 0xce, 0x87, 0x0b, 0x07, 0x02, 0x9b, 0xfc, 0xdb, 0x2d, 0xce,
+        0x28, 0xd9, 0x59, 0xf2, 0x81, 0x5b, 0x16, 0xf8, 0x17, 0x98,
+    };
+    static const uint8_t h[32] = {
+        0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef, 0x01, 0x23,
+        0x45, 0x67, 0x89, 0xab, 0xcd, 0xef, 0x01, 0x23, 0x45, 0x67,
+        0x89, 0xab, 0xcd, 0xef, 0x01, 0x23, 0x45, 0x67, 0x89, 0xab,
+        0xcd, 0xef,
+    };
+    static const uint8_t expected[32] = {
+        0x5a, 0x10, 0x17, 0x2d, 0x23, 0x92, 0xd8, 0xe0, 0x2f, 0x3f,
+        0x67, 0x1e, 0x13, 0x51, 0x13, 0x34, 0x0d, 0x17, 0xff, 0x17,
+        0x4f, 0x65, 0x0b, 0x57, 0xd7, 0x68, 0xc1, 0xc6, 0x5e, 0x4d,
+        0xe9, 0xe4,
+    };
+    uint8_t out[32];
+    uint8_t y_parity = 0;
+    assert_int_equal(crypto_tr_tweak_pubkey(pubkey, h, sizeof(h), &y_parity, out),
+                     0);
+    assert_int_equal(y_parity, 1);
+    assert_memory_equal(out, expected, 32);
+}
+
+static void test_crypto_tr_tweak_seckey_empty_h(void **state) {
+    (void) state;
+    /* taproot_tweak_seckey(seckey=1, ""). Since pubkey(1) = G has even y,
+     * the tweaked seckey is t = tagged_hash("TapTweak", G_x). */
+    static const uint8_t seckey_1[32] = {
+        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1,
+    };
+    static const uint8_t expected[32] = {
+        0x3c, 0xf5, 0x21, 0x6d, 0x47, 0x6a, 0x5e, 0x63, 0x7b, 0xf0,
+        0xda, 0x67, 0x4e, 0x50, 0xdd, 0xf5, 0x5c, 0x40, 0x32, 0x70,
+        0xdd, 0x36, 0x49, 0x4d, 0xfc, 0xca, 0x43, 0x81, 0x32, 0xfa,
+        0x30, 0xe8,
+    };
+    uint8_t out[32];
+    assert_int_equal(crypto_tr_tweak_seckey(seckey_1, NULL, 0, out), 0);
+    assert_memory_equal(out, expected, 32);
+}
+
+static void test_crypto_tr_tweak_seckey_with_h(void **state) {
+    (void) state;
+    /* taproot_tweak_seckey(seckey=3, h) */
+    static const uint8_t seckey_3[32] = {
+        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 3,
+    };
+    static const uint8_t h[32] = {
+        0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef, 0x01, 0x23,
+        0x45, 0x67, 0x89, 0xab, 0xcd, 0xef, 0x01, 0x23, 0x45, 0x67,
+        0x89, 0xab, 0xcd, 0xef, 0x01, 0x23, 0x45, 0x67, 0x89, 0xab,
+        0xcd, 0xef,
+    };
+    static const uint8_t expected[32] = {
+        0x34, 0xbb, 0x44, 0x56, 0xbb, 0x5d, 0xc8, 0xd1, 0x7e, 0x49,
+        0xca, 0xf2, 0x97, 0x20, 0x04, 0x09, 0x91, 0x5c, 0x33, 0xf7,
+        0x04, 0x04, 0x0a, 0x4c, 0x43, 0x9d, 0x41, 0xe3, 0x10, 0xe2,
+        0x1b, 0xc0,
+    };
+    uint8_t out[32];
+    assert_int_equal(crypto_tr_tweak_seckey(seckey_3, h, sizeof(h), out), 0);
+    assert_memory_equal(out, expected, 32);
+}
+
 int main(void) {
     speculos_bridge_init();
     const struct CMUnitTest tests[] = {
@@ -622,6 +885,18 @@ int main(void) {
         cmocka_unit_test(test_base58_encode_address_four_byte_version),
         cmocka_unit_test(test_crypto_ecdsa_sign_sha256_hash_with_key_known_vector),
         cmocka_unit_test(test_crypto_ecdsa_sign_sha256_hash_with_key_no_optional_outputs),
+        cmocka_unit_test(test_crypto_tr_tagged_hash_init_custom_tag),
+        cmocka_unit_test(test_crypto_tr_tapleaf_hash_init),
+        cmocka_unit_test(test_crypto_tr_lift_x_secp256k1_generator),
+        cmocka_unit_test(test_crypto_tr_lift_x_not_on_curve),
+        cmocka_unit_test(test_crypto_tr_tagged_hash_single_data),
+        cmocka_unit_test(test_crypto_tr_tagged_hash_two_parts),
+        cmocka_unit_test(test_crypto_tr_combine_taptree_hashes_sorted),
+        cmocka_unit_test(test_crypto_tr_combine_taptree_hashes_reversed),
+        cmocka_unit_test(test_crypto_tr_tweak_pubkey_empty_h),
+        cmocka_unit_test(test_crypto_tr_tweak_pubkey_with_h),
+        cmocka_unit_test(test_crypto_tr_tweak_seckey_empty_h),
+        cmocka_unit_test(test_crypto_tr_tweak_seckey_with_h),
     };
     return cmocka_run_group_tests(tests, NULL, NULL);
 }