From c1f0c642df6b024edc0aac16a59328ac084bcdba Mon Sep 17 00:00:00 2001
From: Andrew Kozlik <42678794+andrewkozlik@users.noreply.github.com>
Date: Mon, 2 Sep 2019 12:09:03 +0200
Subject: [PATCH] core: cache seed without passphrase (#478)

---
 core/src/apps/common/cache.py | 11 +++++++++++
 core/src/apps/common/seed.py  | 10 ++++++++--
 2 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/core/src/apps/common/cache.py b/core/src/apps/common/cache.py
index 435cc4771b..e22fd48a7f 100644
--- a/core/src/apps/common/cache.py
+++ b/core/src/apps/common/cache.py
@@ -6,6 +6,7 @@ if False:
     from typing import Optional
 
 _cached_seed = None  # type: Optional[bytes]
+_cached_seed_without_passphrase = None  # type: Optional[bytes]
 _cached_passphrase = None  # type: Optional[str]
 _cached_passphrase_fprint = b"\x00\x00\x00\x00"  # type: bytes
 
@@ -36,6 +37,10 @@ def get_seed() -> Optional[bytes]:
     return _cached_seed
 
 
+def get_seed_without_passphrase() -> Optional[bytes]:
+    return _cached_seed_without_passphrase
+
+
 def get_passphrase() -> Optional[str]:
     return _cached_passphrase
 
@@ -53,6 +58,11 @@ def set_seed(seed: Optional[bytes]) -> None:
     _cached_seed = seed
 
 
+def set_seed_without_passphrase(seed: Optional[bytes]) -> None:
+    global _cached_seed_without_passphrase
+    _cached_seed_without_passphrase = seed
+
+
 def set_passphrase(passphrase: Optional[str]) -> None:
     global _cached_passphrase, _cached_passphrase_fprint
     _cached_passphrase = passphrase
@@ -61,5 +71,6 @@ def set_passphrase(passphrase: Optional[str]) -> None:
 
 def clear(keep_passphrase: bool = False) -> None:
     set_seed(None)
+    set_seed_without_passphrase(None)
     if not keep_passphrase:
         set_passphrase(None)
diff --git a/core/src/apps/common/seed.py b/core/src/apps/common/seed.py
index 3f87aeaba8..82adf40eac 100644
--- a/core/src/apps/common/seed.py
+++ b/core/src/apps/common/seed.py
@@ -126,7 +126,10 @@ def derive_node_without_passphrase(
 ) -> bip32.HDNode:
     if not storage.is_initialized():
         raise Exception("Device is not initialized")
-    seed = mnemonic.get_seed(progress_bar=False)
+    seed = cache.get_seed_without_passphrase()
+    if seed is None:
+        seed = mnemonic.get_seed(progress_bar=False)
+        cache.set_seed_without_passphrase(seed)
     node = bip32.from_seed(seed, curve_name)
     node.derive_path(path)
     return node
@@ -135,7 +138,10 @@ def derive_node_without_passphrase(
 def derive_slip21_node_without_passphrase(path: list) -> Slip21Node:
     if not storage.is_initialized():
         raise Exception("Device is not initialized")
-    seed = mnemonic.get_seed(progress_bar=False)
+    seed = cache.get_seed_without_passphrase()
+    if seed is None:
+        seed = mnemonic.get_seed(progress_bar=False)
+        cache.set_seed_without_passphrase(seed)
     node = Slip21Node(seed)
     node.derive_path(path)
     return node