feat: support zcash for keystone nexus

Keystone/Keystone 3 firmware

b0eb9588 View source ↗

Public commit record

What the developer wrote

Authored by soralit

57/100 · Thin

feat: support zcash for keystone nexus

✓ Descriptive subject✓ Names a concrete action or component✓ Uses a recognizable type or scope! No meaningful explanatory body

The short version

What changed, and why it matters

This commit adds Zcash cryptocurrency support to the Keystone 3 hardware wallet firmware. It registers a new Zcash unified full viewing key type, enables encryption of that key, wires up the user-interface handlers for Zcash transactions, and adjusts build flags so Zcash support is available in non-Bitcoin-only firmware builds. There is no direct evidence in the diff of a security vulnerability; it reads as a feature addition.

Recommended action

No security action required based on this commit alone. Treat as a normal feature review: verify the Zcash key derivation path (M/32'/133'/0') and encrypted UFKV storage logic are correct, and ensure the widened #ifndef BTC_ONLY guard does not expose Zcash code paths in builds that should not include them.

Security signals we found

Feature addition for Zcash support, not a vulnerability fix

Encrypted storage path for Zcash unified full viewing key is introduced

Build configuration guard widened from CYPHERPUNK_VERSION to #ifndef BTC_ONLY

No memory-safety, cryptographic, or authorization flaws visible in the diff

Technical analysis

Evidence from the diff

The patch extends the firmware’s chain table with ZCASH_UFVK_ENCRYPTED_0 and a derivation path of M/32’/133’/0’. It changes the guard around Zcash unified full viewing key encryption from CYPHERPUNK_VERSION to the broader #ifndef BTC_ONLY, and restructures the conditional key-processing logic in AccountPublicSavePublicInfo and TempAccountPublicInfo so the encrypted UFVK branch is taken for non-Bitcoin builds. UI code adds REMAPVIEW_ZCASH entries, a Zcash transaction handler, and includes gui_zcash.h under #ifndef BTC_ONLY instead of only under CYPHERPUNK_VERSION. The Rust zcash app imports transparent key types. A trailing whitespace fix is made in a Bitcoin address constants file.

Changed components

rust/apps/zcash/src/lib.rssrc/crypto/account_public_info.csrc/ui/gui_analyze/gui_resolve_ur.csrc/ui/gui_analyze/multi/web3/gui_general_analyze.hsrc/ui/gui_chain/gui_chain.csrc/ui/gui_chain/gui_chain.hui_simulator/simulator_model.hrust/apps/bitcoin/src/addresses/constants.rs

Inspect captured patch +33 / −13

diff --git a/rust/apps/bitcoin/src/addresses/constants.rs b/rust/apps/bitcoin/src/addresses/constants.rs
index 020afb4..aa2391b 100644
--- a/rust/apps/bitcoin/src/addresses/constants.rs
+++ b/rust/apps/bitcoin/src/addresses/constants.rs
@@ -3,7 +3,7 @@ pub const PUBKEY_ADDRESS_PREFIX_DASH: u8 = 76; // 0x4C
 pub const PUBKEY_ADDRESS_PREFIX_DASH_P2SH: u8 = 16; // 0x10
 pub const PUBKEY_ADDRESS_PREFIX_BCH: u8 = 0; // 0x00
 pub const PUBKEY_ADDRESS_PREFIX_DOGE: u8 = 30; // 0x1E
-pub const PUBKEY_ADDRESS_PREFIX_ZEC_BYTE0: u8 = 0x1C; // 28 
+pub const PUBKEY_ADDRESS_PREFIX_ZEC_BYTE0: u8 = 0x1C; // 28
 pub const PUBKEY_ADDRESS_PREFIX_ZEC_BYTE1: u8 = 0xB8; // 184
 
 pub const SCRIPT_ADDRESS_PREFIX_BTC: u8 = 5; // 0x05
diff --git a/rust/apps/zcash/src/lib.rs b/rust/apps/zcash/src/lib.rs
index 5107d22..59b0d23 100644
--- a/rust/apps/zcash/src/lib.rs
+++ b/rust/apps/zcash/src/lib.rs
@@ -13,6 +13,7 @@ use alloc::{
 use pczt::structs::ParsedPczt;
 use zcash_vendor::{
     pczt::Pczt,
+    transparent::keys::{NonHardenedChildIndex, TransparentKeyScope},
     zcash_keys::keys::{UnifiedAddressRequest, UnifiedFullViewingKey},
     zcash_protocol::consensus::{self},
     zip32,
diff --git a/src/crypto/account_public_info.c b/src/crypto/account_public_info.c
index abb3b0e..133074e 100644
--- a/src/crypto/account_public_info.c
+++ b/src/crypto/account_public_info.c
@@ -524,6 +524,7 @@ static const ChainItem_t g_chainTable[] = {
     {XPUB_TYPE_TON_NATIVE,            TON_NATIVE,    "ton",                      ""                 },
     {PUBLIC_INFO_TON_CHECKSUM,        TON_CHECKSUM,  "ton_checksum",             ""                 },
     {XPUB_TYPE_ZEC_TRANSPARENT_LEGACY,SECP256K1,     "zec_transparent_legacy",   "M/44'/133'/0'"    },
+    {ZCASH_UFVK_ENCRYPTED_0,          ZCASH_UFVK_ENCRYPTED, "zcash_ufvk_0",      "M/32'/133'/0'"    },
 #endif
 
 #ifdef CYPHERPUNK_VERSION
@@ -919,7 +920,7 @@ int32_t AccountPublicSavePublicInfo(uint8_t accountIndex, const char *password,
                 if (g_chainTable[i].cryptoKey == TON_CHECKSUM || g_chainTable[i].cryptoKey == TON_NATIVE) {
                     continue;
                 }
-#ifdef CYPHERPUNK_VERSION
+#ifndef BTC_ONLY
                 //encrypt zcash ufvk
                 if (g_chainTable[i].cryptoKey == ZCASH_UFVK_ENCRYPTED) {
                     char* zcashUfvk = NULL;
@@ -933,14 +934,12 @@ int32_t AccountPublicSavePublicInfo(uint8_t accountIndex, const char *password,
                     memcpy_s(iv_bytes, 16, iv_response->data, 16);
                     free_simple_response_u8(iv_response);
                     xPubResult = rust_aes256_cbc_encrypt(zcashUfvk, password, iv_bytes, 16);
-                } else {
-                    xPubResult = ProcessKeyType(seed, seedLen, g_chainTable[i].cryptoKey, g_chainTable[i].path, icarusMasterKey, ledgerBitbox02Key);
-                }
-#endif
-#ifdef WEB3_VERSION
-                if (g_chainTable[i].cryptoKey == BIP32_ED25519 && isSlip39) {
+#ifdef WEB3_VERSION                    
+                } else if (g_chainTable[i].cryptoKey == BIP32_ED25519 && isSlip39) {
                     xPubResult = cardano_get_pubkey_by_slip23(seed, seedLen, g_chainTable[i].path);
-                } else {
+#endif
+                }
+                else {
                     xPubResult = ProcessKeyType(seed, seedLen, g_chainTable[i].cryptoKey, g_chainTable[i].path, icarusMasterKey, ledgerBitbox02Key);
                 }
 #endif
@@ -1086,7 +1085,7 @@ int32_t TempAccountPublicInfo(uint8_t accountIndex, const char *password, bool s
             if (g_chainTable[i].cryptoKey == TON_CHECKSUM || g_chainTable[i].cryptoKey == TON_NATIVE) {
                 continue;
             }
-#ifdef CYPHERPUNK_VERSION
+#ifndef BTC_ONLY
             //encrypt zcash ufvk
             if (g_chainTable[i].cryptoKey == ZCASH_UFVK_ENCRYPTED) {
                 char* zcashUfvk = NULL;
diff --git a/src/ui/gui_analyze/gui_resolve_ur.c b/src/ui/gui_analyze/gui_resolve_ur.c
index d9232fc..fb627c3 100644
--- a/src/ui/gui_analyze/gui_resolve_ur.c
+++ b/src/ui/gui_analyze/gui_resolve_ur.c
@@ -56,6 +56,7 @@ static SetChainData_t g_chainViewArray[] = {
     {REMAPVIEW_AVAX, (SetChainDataFunc)GuiSetAvaxUrData},
     {REMAPVIEW_IOTA, (SetChainDataFunc)GuiSetIotaUrData},
     {REMAPVIEW_IOTA_SIGN_MESSAGE_HASH, (SetChainDataFunc)GuiSetIotaUrData},
+    {REMAPVIEW_ZCASH, (SetChainDataFunc)GuiSetZcashUrData},
 #endif
 };
 
diff --git a/src/ui/gui_analyze/multi/web3/gui_general_analyze.h b/src/ui/gui_analyze/multi/web3/gui_general_analyze.h
index c508a4e..583019d 100644
--- a/src/ui/gui_analyze/multi/web3/gui_general_analyze.h
+++ b/src/ui/gui_analyze/multi/web3/gui_general_analyze.h
@@ -173,6 +173,13 @@
         GuiGetAvaxGUIData,\
         NULL,\
         FreeAvaxMemory,\
+    },\
+    { \
+        REMAPVIEW_ZCASH, \
+        "{\"name\":\"zcash_page\",\"type\":\"custom_container\",\"pos\":[36,0],\"size\":[408,900],\"bg_color\":0,\"custom_show_func\":\"GuiZcashOverview\"}", \
+        GuiGetZcashGUIData, \
+        NULL, \
+        FreeZcashMemory, \
     }
 #endif
 #endif
diff --git a/src/ui/gui_chain/gui_chain.c b/src/ui/gui_chain/gui_chain.c
index 0194bd3..ad79f99 100644
--- a/src/ui/gui_chain/gui_chain.c
+++ b/src/ui/gui_chain/gui_chain.c
@@ -100,6 +100,7 @@ static const ViewHandlerEntry g_viewHandlerMap[] = {
 
     {TonTx, GuiGetTonSignQrCodeData, NULL, GuiGetTonCheckResult, CHAIN_TON, REMAPVIEW_TON},
     {TonSignProof, GuiGetTonProofSignQrCodeData, NULL, GuiGetTonCheckResult, CHAIN_TON, REMAPVIEW_TON_SIGNPROOF},
+    {ZcashTx, GuiGetZcashSignQrCodeData, NULL, GuiGetZcashCheckResult, CHAIN_ZCASH, REMAPVIEW_ZCASH},
 #endif
 
 #ifdef CYPHERPUNK_VERSION
diff --git a/src/ui/gui_chain/gui_chain.h b/src/ui/gui_chain/gui_chain.h
index 3ebfd2a..19201b9 100644
--- a/src/ui/gui_chain/gui_chain.h
+++ b/src/ui/gui_chain/gui_chain.h
@@ -4,6 +4,7 @@
 #include "gui_animating_qrcode.h"
 #include "gui_btc.h"
 #ifndef BTC_ONLY
+#include "gui_zcash.h"
 #ifdef WEB3_VERSION
 #include "gui_eth.h"
 #include "gui_eth_batch_tx_widgets.h"
@@ -20,7 +21,6 @@
 #include "gui_avax.h"
 #include "gui_iota.h"
 #else
-#include "gui_zcash.h"
 #include "gui_monero.h"
 #endif
 #endif
@@ -92,8 +92,11 @@ typedef enum {
     // cosmos end
 #endif
 
-#ifdef CYPHERPUNK_VERSION
+#ifndef BTC_ONLY
     CHAIN_ZCASH,
+#endif
+
+#ifdef CYPHERPUNK_VERSION
     CHAIN_XMR,
 #endif
     CHAIN_BUTT,
@@ -130,6 +133,7 @@ typedef enum {
     REMAPVIEW_TON,
     REMAPVIEW_TON_SIGNPROOF,
     REMAPVIEW_AVAX,
+    REMAPVIEW_ZCASH,
 #endif
 
 #ifdef CYPHERPUNK_VERSION
diff --git a/ui_simulator/simulator_model.h b/ui_simulator/simulator_model.h
index ba74f25..a412900 100644
--- a/ui_simulator/simulator_model.h
+++ b/ui_simulator/simulator_model.h
@@ -247,7 +247,14 @@ extern bool g_reboot;
         GuiGetAvaxGUIData, \
         NULL, \
         FreeAvaxMemory, \
-    },
+    },\
+    { \
+        REMAPVIEW_ZCASH, \
+        PC_SIMULATOR_PATH "/page_zcash.json", \
+        GuiGetZcashGUIData, \
+        NULL, \
+        FreeZcashMemory, \
+    }
 #endif
 
 #endif
\ No newline at end of file

Risk score

Why this scored 12/100

Our methodology →

Potential impact 0/30

Exploitability 0/25

Stealth signal 0/15

Affected reach 0/15

Confidence 8/10

Evidence quality 4/5

Human-validated context

Community notes

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What the developer wrote

What changed, and why it matters

Security signals we found

Evidence from the diff

Changed components

Why this scored 12/100

Community notes

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