RAHHH

backend/lib/python3.12/site-packages/autobahn/xbr/_wallet.py

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+###############################################################################
+#
+# The MIT License (MIT)
+#
+# Copyright (c) typedef int GmbH
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in
+# all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+# THE SOFTWARE.
+#
+###############################################################################
+
+import hashlib
+from typing import Optional
+import argon2
+import hkdf
+
+
+def stretch_argon2_secret(email: str, password: str, salt: Optional[bytes] = None) -> bytes:
+    """
+    Compute argon2id based secret from user email and password only. This uses Argon2id
+    for stretching a potentially weak user password/PIN and subsequent HKDF based key
+    extending to derive private key material (PKM) for different usage contexts.
+
+    The Argon2 parameters used are the following:
+
+    * kdf ``argon2id-13``
+    * time cost ``4096``
+    * memory cost ``512``
+    * parallelism ``1``
+
+    See `draft-irtf-cfrg-argon2 <https://datatracker.ietf.org/doc/draft-irtf-cfrg-argon2/>`__ and
+    `argon2-cffi <https://argon2-cffi.readthedocs.io/en/stable/>`__.
+
+    :param email: User email.
+    :param password: User password.
+    :param salt: Optional salt to use (must be 16 bytes long). If none is given, compute salt
+        from email as ``salt = SHA256(email)[:16]``.
+    :return: The computed private key material (256b, 32 octets).
+    """
+    if not salt:
+        m = hashlib.sha256()
+        m.update(email.encode('utf8'))
+        salt = m.digest()[:16]
+    assert len(salt) == 16
+
+    pkm = argon2.low_level.hash_secret_raw(
+        secret=password.encode('utf8'),
+        salt=salt,
+        time_cost=4096,
+        memory_cost=512,
+        parallelism=1,
+        hash_len=32,
+        type=argon2.low_level.Type.ID,
+        version=19,
+    )
+
+    return pkm
+
+
+def expand_argon2_secret(pkm: bytes, context: bytes, salt: Optional[bytes] = None) -> bytes:
+    """
+
+    Expand ``pkm`` and ``context`` into a key of length ``bytes`` using
+    HKDF's expand function based on HMAC SHA-512). See the HKDF draft RFC and paper for usage notes.
+
+    :param pkm:
+    :param context:
+    :param salt:
+    :return:
+    """
+    kdf = hkdf.Hkdf(salt=salt, input_key_material=pkm, hash=hashlib.sha512)
+    key = kdf.expand(info=context, length=32)
+    return key
+
+
+def pkm_from_argon2_secret(email: str, password: str, context: str, salt: Optional[bytes] = None) -> bytes:
+    """
+
+    :param email:
+    :param password:
+    :param context:
+    :param salt:
+    :return:
+    """
+    if not salt:
+        m = hashlib.sha256()
+        m.update(email.encode('utf8'))
+        salt = m.digest()[:16]
+    assert len(salt) == 16
+
+    context = context.encode('utf8')
+
+    pkm = stretch_argon2_secret(email=email, password=password, salt=salt)
+    key = expand_argon2_secret(pkm=pkm, context=context, salt=salt)
+
+    return key