Include fingerprint salt in password key derivation

scripts/generate_test_profile.py

@@ -79,7 +79,7 @@ def initialize_profile(
     profile_dir = APP_DIR / fingerprint
     profile_dir.mkdir(parents=True, exist_ok=True)
 
-    seed_key = derive_key_from_password(DEFAULT_PASSWORD)
+    seed_key = derive_key_from_password(DEFAULT_PASSWORD, fingerprint)
     seed_mgr = EncryptionManager(seed_key, profile_dir)
     seed_file = profile_dir / "parent_seed.enc"
     clear_path = profile_dir / "seed_phrase.txt"

src/seedpass/core/manager.py

@@ -510,10 +510,13 @@ class PasswordManager:
                     else 50_000
                 )
                 print("Deriving key...")
+                salt_fp = fingerprint_dir.name
                 if mode == "argon2":
-                    seed_key = derive_key_from_password_argon2(password)
+                    seed_key = derive_key_from_password_argon2(password, salt_fp)
                 else:
-                    seed_key = derive_key_from_password(password, iterations=iterations)
+                    seed_key = derive_key_from_password(
+                        password, salt_fp, iterations=iterations
+                    )
                 seed_mgr = EncryptionManager(seed_key, fingerprint_dir)
                 print("Decrypting seed...")
                 try:
@@ -578,10 +581,13 @@ class PasswordManager:
                 if getattr(self, "config_manager", None)
                 else 50_000
             )
+            salt_fp = fingerprint_dir.name
             if mode == "argon2":
-                seed_key = derive_key_from_password_argon2(password)
+                seed_key = derive_key_from_password_argon2(password, salt_fp)
             else:
-                seed_key = derive_key_from_password(password, iterations=iterations)
+                seed_key = derive_key_from_password(
+                    password, salt_fp, iterations=iterations
+                )
             seed_mgr = EncryptionManager(seed_key, fingerprint_dir)
             self.parent_seed = seed_mgr.decrypt_parent_seed()
             seed_bytes = Bip39SeedGenerator(self.parent_seed).Generate()
@@ -746,14 +752,6 @@ class PasswordManager:
             if password is None:
                 password = prompt_existing_password("Enter your login password: ")
 
-            # Derive encryption key from password
-            iterations = (
-                self.config_manager.get_kdf_iterations()
-                if getattr(self, "config_manager", None)
-                else 50_000
-            )
-            key = derive_key_from_password(password, iterations=iterations)
-
             # Initialize FingerprintManager if not already initialized
             if not self.fingerprint_manager:
                 self.initialize_fingerprint_manager()
@@ -792,6 +790,16 @@ class PasswordManager:
                 print(colored("Error: Seed profile directory not found.", "red"))
                 sys.exit(1)
 
+            # Derive encryption key from password using selected fingerprint
+            iterations = (
+                self.config_manager.get_kdf_iterations()
+                if getattr(self, "config_manager", None)
+                else 50_000
+            )
+            key = derive_key_from_password(
+                password, selected_fingerprint, iterations=iterations
+            )
+
             # Initialize EncryptionManager with key and fingerprint_dir
             self.encryption_manager = EncryptionManager(key, fingerprint_dir)
             self.vault = Vault(self.encryption_manager, fingerprint_dir)
@@ -927,7 +935,9 @@ class PasswordManager:
                     if getattr(self, "config_manager", None)
                     else 50_000
                 )
-                seed_key = derive_key_from_password(password, iterations=iterations)
+                seed_key = derive_key_from_password(
+                    password, fingerprint, iterations=iterations
+                )
 
                 self.encryption_manager = EncryptionManager(index_key, fingerprint_dir)
                 seed_mgr = EncryptionManager(seed_key, fingerprint_dir)
@@ -1077,7 +1087,9 @@ class PasswordManager:
                 if getattr(self, "config_manager", None)
                 else 50_000
             )
-            seed_key = derive_key_from_password(password, iterations=iterations)
+            seed_key = derive_key_from_password(
+                password, fingerprint_dir.name, iterations=iterations
+            )
 
             self.encryption_manager = EncryptionManager(index_key, fingerprint_dir)
             seed_mgr = EncryptionManager(seed_key, fingerprint_dir)
@@ -4206,7 +4218,9 @@ class PasswordManager:
             if confirm_action("Encrypt export with a password? (Y/N): "):
                 password = prompt_new_password()
                 iterations = self.config_manager.get_kdf_iterations()
-                key = derive_key_from_password(password, iterations=iterations)
+                key = derive_key_from_password(
+                    password, self.current_fingerprint, iterations=iterations
+                )
                 enc_mgr = EncryptionManager(key, dest.parent)
                 data_bytes = enc_mgr.encrypt_data(json_data.encode("utf-8"))
                 dest = dest.with_suffix(dest.suffix + ".enc")
@@ -4421,7 +4435,9 @@ class PasswordManager:
             new_key = derive_index_key(self.parent_seed)
 
             iterations = self.config_manager.get_kdf_iterations()
-            seed_key = derive_key_from_password(new_password, iterations=iterations)
+            seed_key = derive_key_from_password(
+                new_password, self.current_fingerprint, iterations=iterations
+            )
             seed_mgr = EncryptionManager(seed_key, self.fingerprint_dir)
 
             new_enc_mgr = EncryptionManager(new_key, self.fingerprint_dir)

src/tests/helpers.py

@@ -11,6 +11,7 @@ from utils.key_derivation import (
     derive_index_key,
     derive_key_from_password,
 )
+from utils.fingerprint import generate_fingerprint
 
 TEST_SEED = "abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon about"
 TEST_PASSWORD = "pw"
@@ -22,7 +23,8 @@ def create_vault(
     password: str = TEST_PASSWORD,
 ) -> tuple[Vault, EncryptionManager]:
     """Create a Vault initialized for tests."""
-    seed_key = derive_key_from_password(password)
+    fp = generate_fingerprint(seed)
+    seed_key = derive_key_from_password(password, fp)
     seed_mgr = EncryptionManager(seed_key, dir_path)
     seed_mgr.encrypt_parent_seed(seed)
 

src/tests/test_concurrency_stress.py

@@ -3,6 +3,7 @@ from pathlib import Path
 from multiprocessing import Process, Queue
 import pytest
 from helpers import TEST_SEED, TEST_PASSWORD
+from utils.fingerprint import generate_fingerprint
 
 sys.path.append(str(Path(__file__).resolve().parents[1]))
 
@@ -51,7 +52,8 @@ def _backup(index_key: bytes, dir_path: Path, loops: int, out: Queue) -> None:
 @pytest.mark.parametrize("_", range(3))
 def test_concurrency_stress(tmp_path: Path, loops: int, _):
     index_key = derive_index_key(TEST_SEED)
-    seed_key = derive_key_from_password(TEST_PASSWORD)
+    fp = generate_fingerprint(TEST_SEED)
+    seed_key = derive_key_from_password(TEST_PASSWORD, fp)
     EncryptionManager(seed_key, tmp_path).encrypt_parent_seed(TEST_SEED)
     enc = EncryptionManager(index_key, tmp_path)
     Vault(enc, tmp_path).save_index({"counter": 0})

src/tests/test_fuzz_key_derivation.py

@@ -9,6 +9,7 @@ from utils.key_derivation import (
     derive_key_from_password_argon2,
     derive_index_key,
 )
+from utils.fingerprint import generate_fingerprint
 from seedpass.core.encryption import EncryptionManager
 
 
@@ -33,12 +34,13 @@ cfg_values = st.one_of(
 def test_fuzz_key_round_trip(password, seed_bytes, config, mode, tmp_path: Path):
     """Ensure EncryptionManager round-trips arbitrary data."""
     seed_phrase = Mnemonic("english").to_mnemonic(seed_bytes)
+    fp = generate_fingerprint(seed_phrase)
     if mode == "argon2":
         key = derive_key_from_password_argon2(
-            password, time_cost=1, memory_cost=8, parallelism=1
+            password, fp, time_cost=1, memory_cost=8, parallelism=1
         )
     else:
-        key = derive_key_from_password(password, iterations=1)
+        key = derive_key_from_password(password, fp, iterations=1)
 
     enc_mgr = EncryptionManager(key, tmp_path)
 

src/tests/test_index_import_export.py

@@ -4,6 +4,7 @@ from tempfile import TemporaryDirectory
 import pytest
 import sys
 from helpers import create_vault, TEST_SEED, TEST_PASSWORD
+from utils.fingerprint import generate_fingerprint
 
 sys.path.append(str(Path(__file__).resolve().parents[1]))
 
@@ -16,7 +17,8 @@ PASSWORD = "passw0rd"
 
 
 def setup_vault(tmp: Path) -> Vault:
-    seed_key = derive_key_from_password(PASSWORD)
+    fp = generate_fingerprint(SEED)
+    seed_key = derive_key_from_password(PASSWORD, fp)
     seed_mgr = EncryptionManager(seed_key, tmp)
     seed_mgr.encrypt_parent_seed(SEED)
 

src/tests/test_kdf_modes.py

@@ -19,10 +19,11 @@ TEST_PASSWORD = "pw"
 
 def _setup_profile(tmp: Path, mode: str):
     argon_kwargs = dict(time_cost=1, memory_cost=8, parallelism=1)
+    fp = tmp.name
     if mode == "argon2":
-        seed_key = derive_key_from_password_argon2(TEST_PASSWORD, **argon_kwargs)
+        seed_key = derive_key_from_password_argon2(TEST_PASSWORD, fp, **argon_kwargs)
     else:
-        seed_key = derive_key_from_password(TEST_PASSWORD, iterations=1)
+        seed_key = derive_key_from_password(TEST_PASSWORD, fp, iterations=1)
     EncryptionManager(seed_key, tmp).encrypt_parent_seed(TEST_SEED)
 
     index_key = derive_index_key(TEST_SEED)
@@ -44,7 +45,7 @@ def _make_pm(tmp: Path, cfg: ConfigManager):
     pm.encryption_mode = EncryptionMode.SEED_ONLY
     pm.config_manager = cfg
     pm.fingerprint_dir = tmp
-    pm.current_fingerprint = "fp"
+    pm.current_fingerprint = tmp.name
     pm.verify_password = lambda pw: True
     return pm
 
@@ -65,7 +66,9 @@ def test_setup_encryption_manager_kdf_modes(monkeypatch):
             if mode == "argon2":
                 monkeypatch.setattr(
                     "seedpass.core.manager.derive_key_from_password_argon2",
-                    lambda pw: derive_key_from_password_argon2(pw, **argon_kwargs),
+                    lambda pw, fp: derive_key_from_password_argon2(
+                        pw, fp, **argon_kwargs
+                    ),
                 )
             monkeypatch.setattr(PasswordManager, "initialize_bip85", lambda self: None)
             monkeypatch.setattr(

src/tests/test_key_derivation.py

@@ -10,8 +10,9 @@ from utils.key_derivation import (
 
 def test_derive_key_deterministic():
     password = "correct horse battery staple"
-    key1 = derive_key_from_password(password, iterations=1)
+    fp = "fp"
-    key2 = derive_key_from_password(password, iterations=1)
+    key1 = derive_key_from_password(password, fp, iterations=1)
+    key2 = derive_key_from_password(password, fp, iterations=1)
     assert key1 == key2
     assert len(key1) == 44
     logging.info("Deterministic key derivation succeeded")
@@ -19,7 +20,7 @@ def test_derive_key_deterministic():
 
 def test_derive_key_empty_password_error():
     with pytest.raises(ValueError):
-        derive_key_from_password("")
+        derive_key_from_password("", "fp")
     logging.info("Empty password correctly raised ValueError")
 
 
@@ -38,7 +39,12 @@ def test_derive_index_key_seed_only():
 
 def test_argon2_key_deterministic():
     pw = "correct horse battery staple"
-    k1 = derive_key_from_password_argon2(pw, time_cost=1, memory_cost=8, parallelism=1)
+    fp = "fp"
-    k2 = derive_key_from_password_argon2(pw, time_cost=1, memory_cost=8, parallelism=1)
+    k1 = derive_key_from_password_argon2(
+        pw, fp, time_cost=1, memory_cost=8, parallelism=1
+    )
+    k2 = derive_key_from_password_argon2(
+        pw, fp, time_cost=1, memory_cost=8, parallelism=1
+    )
     assert k1 == k2
     assert len(k1) == 44

src/tests/test_password_unlock_after_change.py

@@ -14,19 +14,22 @@ from seedpass.core.backup import BackupManager
 from seedpass.core.config_manager import ConfigManager
 from seedpass.core.manager import PasswordManager, EncryptionMode
 from utils.key_derivation import derive_index_key, derive_key_from_password
+from utils.fingerprint import generate_fingerprint
 
 SEED = "abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon about"
 
 
 def test_password_change_and_unlock(monkeypatch):
     with TemporaryDirectory() as tmpdir:
-        fp = Path(tmpdir)
+        fp_name = generate_fingerprint(SEED)
+        fp = Path(tmpdir) / fp_name
+        fp.mkdir()
         old_pw = "oldpw"
         new_pw = "newpw"
 
         # initial encryption setup
         index_key = derive_index_key(SEED)
-        seed_key = derive_key_from_password(old_pw)
+        seed_key = derive_key_from_password(old_pw, fp_name)
         enc_mgr = EncryptionManager(index_key, fp)
         seed_mgr = EncryptionManager(seed_key, fp)
         vault = Vault(enc_mgr, fp)
@@ -54,7 +57,7 @@ def test_password_change_and_unlock(monkeypatch):
         pm.vault = vault
         pm.password_generator = SimpleNamespace(encryption_manager=enc_mgr)
         pm.fingerprint_dir = fp
-        pm.current_fingerprint = "fp"
+        pm.current_fingerprint = fp_name
         pm.parent_seed = SEED
         pm.nostr_client = SimpleNamespace(
             publish_snapshot=lambda *a, **k: (None, "abcd")

src/tests/test_portable_backup.py

@@ -15,6 +15,7 @@ from seedpass.core.backup import BackupManager
 from seedpass.core.config_manager import ConfigManager
 from seedpass.core.portable_backup import export_backup, import_backup
 from utils.key_derivation import derive_index_key, derive_key_from_password
+from utils.fingerprint import generate_fingerprint
 
 
 SEED = "abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon about"
@@ -22,7 +23,8 @@ PASSWORD = "passw0rd"
 
 
 def setup_vault(tmp: Path):
-    seed_key = derive_key_from_password(PASSWORD)
+    fp = generate_fingerprint(SEED)
+    seed_key = derive_key_from_password(PASSWORD, fp)
     seed_mgr = EncryptionManager(seed_key, tmp)
     seed_mgr.encrypt_parent_seed(SEED)
 
@@ -126,7 +128,8 @@ def test_export_creates_additional_backup_and_import(monkeypatch):
     with TemporaryDirectory() as td, TemporaryDirectory() as extra:
         tmp = Path(td)
 
-        seed_key = derive_key_from_password(PASSWORD)
+        fp = generate_fingerprint(SEED)
+        seed_key = derive_key_from_password(PASSWORD, fp)
         seed_mgr = EncryptionManager(seed_key, tmp)
         seed_mgr.encrypt_parent_seed(SEED)
 

src/tests/test_seed_import.py

@@ -3,6 +3,7 @@ from pathlib import Path
 from tempfile import TemporaryDirectory
 from helpers import TEST_PASSWORD
 from utils.key_derivation import derive_key_from_password
+from utils.fingerprint import generate_fingerprint
 from mnemonic import Mnemonic
 
 sys.path.append(str(Path(__file__).resolve().parents[1]))
@@ -13,10 +14,10 @@ from seedpass.core.manager import PasswordManager, EncryptionMode
 
 def test_seed_encryption_round_trip():
     with TemporaryDirectory() as tmpdir:
-        key = derive_key_from_password(TEST_PASSWORD)
-        enc_mgr = EncryptionManager(key, Path(tmpdir))
-
         seed = Mnemonic("english").generate(strength=128)
+        fp = generate_fingerprint(seed)
+        key = derive_key_from_password(TEST_PASSWORD, fp)
+        enc_mgr = EncryptionManager(key, Path(tmpdir))
         enc_mgr.encrypt_parent_seed(seed)
         decrypted = enc_mgr.decrypt_parent_seed()
 

src/tests/test_seed_migration.py

@@ -4,6 +4,7 @@ from cryptography.fernet import Fernet
 
 from helpers import TEST_PASSWORD, TEST_SEED
 from utils.key_derivation import derive_key_from_password
+from utils.fingerprint import generate_fingerprint
 
 sys.path.append(str(Path(__file__).resolve().parents[1]))
 
@@ -11,7 +12,8 @@ from seedpass.core.encryption import EncryptionManager
 
 
 def test_parent_seed_migrates_from_fernet(tmp_path: Path) -> None:
-    key = derive_key_from_password(TEST_PASSWORD)
+    fp = generate_fingerprint(TEST_SEED)
+    key = derive_key_from_password(TEST_PASSWORD, fp)
     fernet = Fernet(key)
     encrypted = fernet.encrypt(TEST_SEED.encode())
     legacy_file = tmp_path / "parent_seed.enc"

src/utils/key_derivation.py

@@ -45,7 +45,9 @@ DEFAULT_ENCRYPTION_MODE = EncryptionMode.SEED_ONLY
 TOTP_PURPOSE = 39
 
 
-def derive_key_from_password(password: str, iterations: int = 100_000) -> bytes:
+def derive_key_from_password(
+    password: str, fingerprint: Union[str, bytes], iterations: int = 100_000
+) -> bytes:
     """
     Derives a Fernet-compatible encryption key from the provided password using PBKDF2-HMAC-SHA256.
 
@@ -55,7 +57,9 @@ def derive_key_from_password(password: str, iterations: int = 100_000) -> bytes:
 
     Parameters:
         password (str): The user's password.
-        iterations (int, optional): Number of iterations for the PBKDF2 algorithm. Defaults to 100,000.
+        fingerprint (str | bytes): Seed fingerprint or precomputed salt.
+        iterations (int, optional): Number of iterations for the PBKDF2 algorithm.
+            Defaults to 100,000.
 
     Returns:
         bytes: A URL-safe base64-encoded encryption key suitable for Fernet.
@@ -74,13 +78,19 @@ def derive_key_from_password(password: str, iterations: int = 100_000) -> bytes:
     normalized_password = unicodedata.normalize("NFKD", password).strip()
     password_bytes = normalized_password.encode("utf-8")
 
+    # Derive a deterministic salt from the fingerprint
+    if isinstance(fingerprint, bytes):
+        salt = fingerprint
+    else:
+        salt = hashlib.sha256(fingerprint.encode()).digest()[:16]
+
     try:
         # Derive the key using PBKDF2-HMAC-SHA256
         logger.debug("Starting key derivation from password.")
         key = hashlib.pbkdf2_hmac(
             hash_name="sha256",
             password=password_bytes,
-            salt=b"",  # No salt for deterministic key derivation
+            salt=salt,
             iterations=iterations,
             dklen=32,  # 256-bit key for Fernet
         )
@@ -99,6 +109,7 @@ def derive_key_from_password(password: str, iterations: int = 100_000) -> bytes:
 
 def derive_key_from_password_argon2(
     password: str,
+    fingerprint: Union[str, bytes],
     *,
     time_cost: int = 2,
     memory_cost: int = 64 * 1024,
@@ -118,9 +129,14 @@ def derive_key_from_password_argon2(
     try:
         from argon2.low_level import hash_secret_raw, Type
 
+        if isinstance(fingerprint, bytes):
+            salt = fingerprint
+        else:
+            salt = hashlib.sha256(fingerprint.encode()).digest()[:16]
+
         key = hash_secret_raw(
             secret=normalized,
-            salt=b"\x00" * 16,
+            salt=salt,
             time_cost=time_cost,
             memory_cost=memory_cost,
             parallelism=parallelism,