fix: deepcopy in reencrypt/decrypt_record so input is not mutated

both used record.copy() (shallow), leaving unencrypted mutable fields shared between the input and the returned dict, violating the documented 'input is not mutated' contract. switched to copy.deepcopy.

Signed-off-by: disqualifier <dev@disqualifier.me>

README.md

@@ -11,13 +11,13 @@ and storage-agnostic.
 `requirements.txt`:
 
 ```
-envelope_crypto @ git+ssh://git@git.rethinkstudios.io/rethink-public/envelope_crypto.git@v0.1.0
+envelope_crypto @ git+ssh://git@git.rethinkstudios.io/rethink-public/envelope_crypto.git@v0.1.1
 ```
 
 Direct:
 
 ```bash
-pip install "envelope_crypto @ git+ssh://git@git.rethinkstudios.io/rethink-public/envelope_crypto.git@v0.1.0"
+pip install "envelope_crypto @ git+ssh://git@git.rethinkstudios.io/rethink-public/envelope_crypto.git@v0.1.1"
 ```
 
 Requires `cryptography` (pulled transitively).
@@ -37,10 +37,10 @@ openssl rsa -in local_priv.pem -pubout -out local_pub.pem
 from envelope_crypto import EnvelopeCrypto
 
 # generate the DEK and wrap it for this system in one call
-crypto, fingerprint, wrapped = EnvelopeCrypto.bootstrap(cfg.local_pub)
+crypto, fingerprint, wrapped = EnvelopeCrypto.bootstrap("public_key.pem")
 
 # verify the keypair actually round-trips BEFORE storing anything
-crypto.self_test(cfg.local_pub, cfg.local_priv)        # raises if keys don't pair
+crypto.self_test("public_key.pem", "private_key.pem")        # raises if keys don't pair
 
 # store the wrapped key — this is now the ONLY record of the DEK
 await db.create_document("keys", {"_id": fingerprint, "key": wrapped})
@@ -53,11 +53,11 @@ re-derived each boot by unwrapping. **Never persist the plaintext key.**
 
 ```python
 crypto = EnvelopeCrypto()
-fingerprint = crypto.get_rsa_key_fingerprint(cfg.local_pub)
+fingerprint = crypto.get_rsa_key_fingerprint("public_key.pem")
 record = await db.get_document("keys", {"_id": fingerprint})
 if not record:
     raise RuntimeError("this system is not authorized")
-crypto.initialize(crypto.decrypt_aes_key_with_rsa(record["key"], cfg.local_priv))
+crypto.initialize(crypto.decrypt_aes_key_with_rsa(record["key"], "private_key.pem"))
 bot.crypto = crypto
 ```
 

pyproject.toml

@@ -4,7 +4,7 @@ build-backend = "hatchling.build"
 
 [project]
 name = "envelope_crypto"
-version = "0.1.0"
+version = "0.1.1"
 description = "Envelope encryption (RSA-OAEP wrapped AES-256-GCM) for dict records — config-free, storage-agnostic, installable."
 requires-python = ">=3.10"
 dependencies = [

src/envelope_crypto/envelope_crypto.py

@@ -17,15 +17,15 @@ envelope-encryption pattern used by KMS-style systems.
 first-time setup: generate the DEK and wrap it for the first system in one call,
 then verify the pipeline before storing anything:
 
-    crypto, fingerprint, wrapped = EnvelopeCrypto.bootstrap(cfg.local_pub)
-    crypto.self_test(cfg.local_pub, cfg.local_priv)    # raises if anything is wrong
+    crypto, fingerprint, wrapped = EnvelopeCrypto.bootstrap("public_key.pem")
+    crypto.self_test("public_key.pem", "private_key.pem")    # raises if anything is wrong
     caller_store({"_id": fingerprint, "key": wrapped}) # the only record of the DEK
 
 boot (already set up): fingerprint own pubkey, fetch the wrapped DEK, unwrap:
 
-    fp = crypto.get_rsa_key_fingerprint(cfg.local_pub)
+    fp = crypto.get_rsa_key_fingerprint("public_key.pem")
     record = caller_lookup(fp)
-    crypto.initialize(crypto.decrypt_aes_key_with_rsa(record["key"], cfg.local_priv))
+    crypto.initialize(crypto.decrypt_aes_key_with_rsa(record["key"], "private_key.pem"))
 
 authorize another system (this instance must already hold the DEK):
 
@@ -54,6 +54,7 @@ function variants are the same functions — use whichever fits your storage.
 """
 
 import os
+import copy
 import json
 import base64
 import hashlib
@@ -147,9 +148,15 @@ class EnvelopeCrypto:
         return key
 
     def get_rsa_key_fingerprint(
-        self, key_path_or_data: str, is_private: bool = False, is_file: bool = True
+        self, key_path_or_data: str, is_private: bool = False, is_file: bool = True,
+        password: Optional[str] = None,
     ) -> str:
-        """return a base64 SHA-256 fingerprint of an RSA key for identification"""
+        """return a base64 SHA-256 fingerprint of an RSA key for identification
+
+        for an encrypted private key (is_private=True), pass its `password`; an
+        unencrypted key ignores it. fingerprinting always uses the public half, so a
+        private and its public key produce the same fingerprint.
+        """
         if is_file:
             with open(key_path_or_data, "rb") as key_file:
                 key_data = key_file.read()
@@ -161,7 +168,9 @@ class EnvelopeCrypto:
             )
 
         if is_private:
-            private_key = serialization.load_pem_private_key(key_data, password=None)
+            private_key = serialization.load_pem_private_key(
+                key_data, password=password.encode() if password else None
+            )
             public_key = private_key.public_key()
         else:
             try:
@@ -305,7 +314,7 @@ class EnvelopeCrypto:
         if not self.master_key:
             raise ValueError("destination not initialized with data key")
 
-        result = record.copy()
+        result = copy.deepcopy(record)
         for key, value in record.items():
             if isinstance(value, dict) and value.get("secure") is True and "iv" in value and "data" in value:
                 result[key] = self.encrypt_data(source_crypto.decrypt_data(value))
@@ -353,7 +362,7 @@ def decrypt_record(crypto: EnvelopeCrypto, record, traversal_level: int = 2) ->
     if not isinstance(record, dict):
         return record
 
-    result = record.copy()
+    result = copy.deepcopy(record)
     for key, value in record.items():
         if isinstance(value, dict) and value.get("secure") is True and "iv" in value and "data" in value:
             try: