docs: compress prose/module docstrings, em-dash->hyphen (de-bloat wave 1)

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

README.md

@@ -11,18 +11,18 @@ and storage-agnostic.
 `requirements.txt`:
 
 ```
-envelope_crypto @ git+ssh://git@git.rethinkstudios.io/rethink-public/envelope_crypto.git@v0.1.6
+envelope_crypto @ git+ssh://git@git.rethinkstudios.io/rethink-public/envelope_crypto.git@v0.1.7
 ```
 
 Direct:
 
 ```bash
-pip install "envelope_crypto @ git+ssh://git@git.rethinkstudios.io/rethink-public/envelope_crypto.git@v0.1.6"
+pip install "envelope_crypto @ git+ssh://git@git.rethinkstudios.io/rethink-public/envelope_crypto.git@v0.1.7"
 ```
 
 Requires `cryptography` (pulled transitively).
 
-Drop the `@v0.1.6` suffix from the line above to install the latest unpinned.
+Drop the `@v0.1.7` suffix from the line above to install the latest unpinned.
 
 ## First-time setup
 

pyproject.toml

@@ -4,7 +4,7 @@ build-backend = "hatchling.build"
 
 [project]
 name = "envelope_crypto"
-version = "0.1.6"
+version = "0.1.7"
 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

@@ -2,12 +2,11 @@
 envelope encryption for dict records
 
 hybrid encryption: a random AES-256-GCM data key (DEK) encrypts the data, wrapped
-(RSA-OAEP) per authorized system's public key (KEK) for distribution. the wrapped
+(RSA-OAEP) per authorized system's public key (KEK) for distribution and stored by
-key is stored by the caller, keyed by fingerprint; each system unwraps its own copy
+the caller, keyed by fingerprint. RSA-envelope only - a non-RSA key (e.g. Ed25519/EC)
-with its private key. same pattern KMS-style systems use. RSA-envelope only — a
+loads and fingerprints fine but raises ValueError at wrap/unwrap. never logs key
-non-RSA key (e.g. Ed25519/EC) loads and fingerprints fine but raises ValueError at
+material (DEK, PEM, wrapped key) - only fingerprints and counts. config-free and
-wrap/unwrap. never logs key material (DEK, PEM, wrapped key) — only fingerprints
+storage-agnostic; see README for bootstrap/boot/authorize/rotate flows.
-and counts.
 
     from envelope_crypto import EnvelopeCrypto
 
@@ -16,54 +15,9 @@ and counts.
     enc = crypto.encrypt_data({"ssn": "..."})          # -> {secure, iv, data}
     plain = crypto.decrypt_data(enc)                   # -> original
 
-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("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("public_key.pem")
-    record = caller_lookup(fp)
-    crypto.initialize(crypto.decrypt_aes_key_with_rsa(record["key"], "private_key.pem"))
-
-authorize another system (this instance must already hold the DEK):
-
-    fp, wrapped = crypto.authorize_system(other_pub_path)
-    caller_store({"_id": fp, "key": wrapped})
-
-deauthorize: caller deletes that fingerprint's record. stops future unwraps but
-does not revoke a DEK already in a running system's memory — rotate if compromised.
-
-rotate (new DEK + re-encrypt): generate a new DEK, wrap for the still-authorized
-set, then re-encrypt existing records old -> new:
-
-    new_key, wrapped = crypto.rotate_master_key([pub_a, pub_b])
-    new_crypto = EnvelopeCrypto(); new_crypto.initialize(new_key)
-    for record in caller_iter():
-        caller_update(new_crypto.reencrypt(crypto, record))
-
-reencrypt/is_encrypted_record/decrypt_record all detect a bare {secure, iv, data}
-blob used AS the whole record (file-storage pattern), not just blobs nested under a
-key. reencrypt fails loud (raises) rather than silently leaving a field under the
-old key — including a blob nested deeper than `traversal_level`; is_encrypted_record
-falls back to an unbounded-depth scan past traversal_level to reliably catch
-leftovers as a post-rotation audit.
-
-config-free: the host supplies the DEK and RSA key paths; this lib never imports
-config, configures logging, or touches a database. storage-agnostic — the
-encrypted blob is a plain dict; store it in mongo, a sql json column, or a file.
-
-encrypt_data/decrypt_data round-trip a dict only when every key is a str — json
-(the wire format) has no other key type, so encrypt_data raises TypeError on a
-non-str key (e.g. an int-keyed dict of discord snowflakes) rather than silently
-stringifying it and losing the original key on decrypt.
-
 naming: EnvelopeCrypto is canonical. PCICrypto / DocumentCrypto / RecordCrypto are
 aliases (PCICrypto is a deprecated legacy alias). the document/record/dict function
-variants are the same functions — use whichever fits your storage.
+variants are the same functions - use whichever fits your storage.
 """
 
 import os
@@ -84,24 +38,14 @@ _log = logging.getLogger(__name__)
 
 
 def _password_mismatch_message(pw: Optional[bytes]) -> str:
-    """clear ValueError text for a TypeError raised by a password/encryption mismatch
+    """clear ValueError text for a TypeError raised by a password/encryption mismatch"""
-
-    cryptography raises TypeError for both directions: encrypted key + no password,
-    and unencrypted key + a password given. branch on which the caller supplied so
-    the message matches the actual case instead of always claiming "encrypted".
-    """
     if pw is not None:
         return "password was given but private key is not encrypted"
     return "private key is encrypted but no password was provided"
 
 
 def _load_private_key(key_data: bytes, pw: Optional[bytes]):
-    """load a PEM or OpenSSH private key, normalizing the password/encryption mismatch error
+    """load a PEM or OpenSSH private key, normalizing the password/encryption mismatch error"""
-
-    cryptography raises TypeError for a password/encryption mismatch (PEM raises it on
-    the first call; OpenSSH raises it inside the openssh fallback), normalized here to a
-    clear ValueError so callers see one error type with a message matching the actual case.
-    """
     try:
         return serialization.load_pem_private_key(key_data, password=pw)
     except ValueError as error:
@@ -111,8 +55,6 @@ def _load_private_key(key_data: bytes, pw: Optional[bytes]):
             except TypeError as ssh_error:
                 raise ValueError(_password_mismatch_message(pw)) from ssh_error
         if pw is not None:
-            # a password was given but the PEM load still failed — most likely a wrong
-            # password; give a clearer message than cryptography's raw "Bad decrypt"
             raise ValueError("could not load private key (wrong password or malformed key)") from error
         raise error
     except TypeError as error:
@@ -120,11 +62,7 @@ def _load_private_key(key_data: bytes, pw: Optional[bytes]):
 
 
 def _fingerprint_of(public_key) -> str:
-    """base64 SHA-256 fingerprint of an already-loaded public key
+    """base64 SHA-256 fingerprint of an already-loaded public key"""
-
-    factored so callers that already hold a loaded key (e.g. encrypt_aes_key_with_rsa)
-    don't re-open and re-parse the key file just to fingerprint it.
-    """
     key_bytes = public_key.public_bytes(
         encoding=serialization.Encoding.DER,
         format=serialization.PublicFormat.SubjectPublicKeyInfo,
@@ -140,11 +78,7 @@ def _is_blob(value: Any) -> bool:
 
 
 def _has_encrypted_field(record: Any) -> bool:
-    """unbounded-depth scan: does record (or anything nested under it) contain a blob
+    """unbounded-depth scan: does record (or anything nested under it) contain a blob"""
-
-    used to detect a blob left behind by a depth-limited traversal — no traversal_level
-    cutoff here, since the whole point is to catch what a bounded pass would miss.
-    """
     if not isinstance(record, dict):
         return False
     if _is_blob(record):
@@ -153,24 +87,13 @@ def _has_encrypted_field(record: Any) -> bool:
 
 
 def _require_rsa(key) -> None:
-    """raise ValueError unless key is an RSA public or private key
+    """raise ValueError unless key is an RSA public or private key"""
-
-    this lib is RSA-envelope only: get_rsa_key_fingerprint accepts any key type
-    (fingerprinting is algorithm-agnostic), but wrap/unwrap calls RSA-OAEP methods
-    that don't exist on e.g. Ed25519/EC keys and would otherwise crash raw with an
-    AttributeError far from a clear cause.
-    """
     if not isinstance(key, (rsa.RSAPublicKey, rsa.RSAPrivateKey)):
         raise ValueError(f"RSA key required for envelope wrap/unwrap, got {type(key).__name__}")
 
 
 def _load_public_key(key_data: bytes):
-    """load a PEM or OpenSSH public key, normalizing non-key input to ValueError
+    """load a PEM or OpenSSH public key, normalizing non-key input to ValueError"""
-
-    load_ssh_public_key raises UnsupportedAlgorithm (not ValueError) on non-SSH/garbage
-    input; normalize it so a bad public key always surfaces as a clear ValueError,
-    consistent with the private-key path.
-    """
     try:
         return serialization.load_pem_public_key(key_data)
     except ValueError:
@@ -195,10 +118,20 @@ class EnvelopeCrypto:
     def bootstrap(cls, rsa_public_key: str, is_file: bool = True) -> Tuple["EnvelopeCrypto", str, str]:
         """first-time setup: generate a DEK and wrap it for the first system
 
-        returns (crypto, fingerprint, wrapped_key) — an initialized instance plus
+        the plaintext DEK is never returned or persisted; it survives only as the
-        the record to store as the first authorization. the plaintext DEK is never
+        wrapped copy. run self_test before storing to confirm the keypair round-trips.
-        returned or persisted; it survives only as the wrapped copy. run self_test
+
-        before storing to confirm the keypair round-trips.
+        Args:
+            rsa_public_key: path to (or, if is_file=False, raw PEM/OpenSSH data of)
+                the first system's RSA public key.
+            is_file: True (default) treats rsa_public_key as a path.
+
+        Returns:
+            (crypto, fingerprint, wrapped_key): an initialized instance plus the
+            record to store as the first authorization.
+
+        Raises:
+            ValueError: rsa_public_key is not an RSA key, or is malformed.
         """
         crypto = cls()
         crypto.initialize(crypto.create_aes_key())
@@ -212,10 +145,23 @@ class EnvelopeCrypto:
         """verify the full pipeline against a keypair; raises on any mismatch
 
         round-trips sample data through this instance's DEK, then wraps and unwraps
-        the DEK with the given keypair, confirming they match. run after bootstrap
+        the DEK with the given keypair. run after bootstrap or as a health check.
-        (or as a health check) to catch a bad keypair or wrong path before relying
+
-        on it. is_file threads through to both key loads (is_file=False treats both
+        Args:
-        as in-memory PEM/OpenSSH data, not paths). returns True on success.
+            rsa_public_key: public half of the keypair to verify (path or, if
+                is_file=False, raw PEM/OpenSSH data).
+            rsa_private_key: private half of the keypair to verify.
+            is_file: True (default) treats both keys as paths; False treats both
+                as in-memory PEM/OpenSSH data.
+            password: password for an encrypted private key, if any.
+
+        Returns:
+            True on success.
+
+        Raises:
+            ValueError: instance not initialized with a data key.
+            RuntimeError: data round-trip fails, or the keypair does not pair
+                (unwrap fails or the recovered key mismatches).
         """
         if not self.master_key:
             raise ValueError("self_test: not initialized with a key")
@@ -243,7 +189,7 @@ class EnvelopeCrypto:
 
         requires exactly 32 bytes (AES-256): a shorter key would silently downgrade
         to AES-128/192 with no warning, and a non-bytes value would otherwise fail
-        late and opaquely at first encrypt/decrypt — both rejected here instead.
+        late and opaquely at first encrypt/decrypt - both rejected here instead.
         never logs the key material itself.
         """
         if not isinstance(master_key, bytes) or len(master_key) != 32:
@@ -273,11 +219,23 @@ class EnvelopeCrypto:
     ) -> str:
         """return a base64 SHA-256 fingerprint of an RSA key for identification
 
-        for an encrypted private key (is_private=True), pass its `password`; an
+        always fingerprints the public half, so a private key and its public key
-        unencrypted key ignores it. always fingerprints the public half, so a
+        match. PEM and OpenSSH accepted (mirrors decrypt_aes_key_with_rsa).
-        private key and its public key match. PEM and OpenSSH accepted (mirrors
+
-        decrypt_aes_key_with_rsa). a password/encryption mismatch raises a clear
+        Args:
-        ValueError (cryptography's raw TypeError normalized here).
+            key_path_or_data: path to (or, if is_file=False, raw PEM/OpenSSH data
+                of) the key.
+            is_private: fingerprint the public half of a private key; pass its
+                `password` if encrypted (an unencrypted key ignores it).
+            is_file: True (default) treats key_path_or_data as a path.
+            password: password for an encrypted private key, if is_private.
+
+        Returns:
+            base64 SHA-256 fingerprint.
+
+        Raises:
+            ValueError: key is malformed, or password/encryption mismatch
+                (cryptography's raw TypeError normalized here).
         """
         if is_file:
             with open(key_path_or_data, "rb") as key_file:
@@ -325,7 +283,6 @@ class EnvelopeCrypto:
                 label=None,
             ),
         )
-        # fingerprint from the already-loaded public_key — no second open/parse of the file
         fingerprint = _fingerprint_of(public_key)
         wrapped_b64 = base64.b64encode(wrapped).decode()
         _log.info("wrapped data key for fingerprint %s", fingerprint[:8])
@@ -337,10 +294,20 @@ class EnvelopeCrypto:
     ) -> bytes:
         """unwrap an AES key with an RSA private key
 
-        is_file defaults to True (rsa_private_key is a path), matching
+        Args:
-        encrypt_aes_key_with_rsa / get_rsa_key_fingerprint; pass is_file=False to
+            encrypted_key_base64: the RSA-OAEP wrapped key, base64-encoded.
-        supply the PEM/OpenSSH key data directly (e.g. an in-memory or vault-sourced
+            rsa_private_key: path to (or, if is_file=False, raw PEM/OpenSSH data
-        key) instead of a file path.
+                of) the private key to unwrap with.
+            is_file: True (default) treats rsa_private_key as a path; pass False
+                to supply PEM/OpenSSH key data directly (e.g. vault-sourced).
+            password: password for an encrypted private key, if any.
+
+        Returns:
+            the unwrapped AES data key.
+
+        Raises:
+            ValueError: rsa_private_key is not an RSA key, is malformed, or a
+                password/encryption mismatch.
         """
         if is_file:
             with open(rsa_private_key, "rb") as key_file:
@@ -366,9 +333,21 @@ class EnvelopeCrypto:
     def authorize_system(self, rsa_public_key: str, is_file: bool = True) -> Tuple[str, str]:
         """wrap the current data key for another system's public key
 
-        returns (fingerprint, wrapped_b64) for the caller to store as that
+        requires this instance to already hold the data key - only an
-        system's key-authorization record. requires this instance to already
+        authorized system can authorize others.
-        hold the data key — only an authorized system can authorize others.
+
+        Args:
+            rsa_public_key: path to (or, if is_file=False, raw PEM/OpenSSH data
+                of) the other system's RSA public key.
+            is_file: True (default) treats rsa_public_key as a path.
+
+        Returns:
+            (fingerprint, wrapped_b64) for the caller to store as that system's
+            key-authorization record.
+
+        Raises:
+            ValueError: this instance is not initialized, or rsa_public_key is
+                not an RSA key.
         """
         if not self.master_key:
             raise ValueError("cannot authorize another system: not initialized")
@@ -379,9 +358,20 @@ class EnvelopeCrypto:
     ) -> Tuple[bytes, Dict[str, str]]:
         """generate a NEW data key and wrap it for each authorized public key
 
-        returns (new_key, {fingerprint: wrapped_b64}). does NOT re-encrypt existing
+        does NOT re-encrypt existing data - build a new instance with the new key
-        data — build a new instance with the new key and call reencrypt() on each
+        and call reencrypt() on each record. systems not in the list get no
-        record. systems not in the list get no wrapped copy (deauthorized).
+        wrapped copy (deauthorized).
+
+        Args:
+            authorized_public_keys: RSA public keys (paths, or raw data if
+                is_file=False) to wrap the new key for.
+            is_file: True (default) treats each entry as a path.
+
+        Returns:
+            (new_key, {fingerprint: wrapped_b64}).
+
+        Raises:
+            ValueError: any entry in authorized_public_keys is not an RSA key.
         """
         new_key = self.create_aes_key()
         wrapped = {}
@@ -396,22 +386,17 @@ class EnvelopeCrypto:
 
         dict keys must be str: json.dumps silently stringifies int/float/bool/None
         keys (e.g. a snowflake-int-keyed dict), which would make decrypt_data return
-        a dict that no longer matches the original by key type or identity — a
+        a dict that no longer matches the original by key type or identity - a
         non-str key is rejected here instead, so the failure is loud at encrypt
         time rather than a silent lookup miss after decrypt.
         """
         if not self.master_key:
             raise ValueError("not initialized with data key")
         if not isinstance(data, (dict, str)):
-            # a non-dict/non-str would .encode()-fail with an opaque AttributeError below;
-            # reject it clearly (decrypt_data only round-trips dict or str anyway)
             raise TypeError(f"encrypt_data expects a dict or str, got {type(data).__name__}")
         if isinstance(data, dict):
             non_str_keys = [key for key in data if not isinstance(key, str)]
             if non_str_keys:
-                # json.dumps would silently stringify these (int/float/bool/None keys),
-                # corrupting the round-trip (decrypt_data would return a dict keyed by
-                # the stringified value) — fail loud instead of coercing
                 raise TypeError(
                     "encrypt_data requires str dict keys, got non-str key(s): "
                     f"{[type(key).__name__ for key in non_str_keys]}"
@@ -430,20 +415,25 @@ class EnvelopeCrypto:
     def decrypt_data(self, encrypted_data: Dict[str, str]) -> Union[Dict[str, Any], str]:
         """decrypt a {secure, iv, data} blob; returns the original dict or string
 
-        encrypt_data only json-encodes dicts (a string is stored verbatim), so decrypt
+        a json-shaped but non-object plaintext ('123', 'true', '[1,2]') round-trips
-        treats a json-OBJECT plaintext as a dict and everything else as a raw string —
+        as a STRING, not int/bool/list. one irreducible ambiguity: a string whose
-        a json-shaped but non-object string ('123', 'true', '[1,2]') round-trips as a
+        exact value is a json object ('{"a":1}') decrypts to a dict, indistinguishable
-        STRING, not int/bool/list. one irreducible ambiguity: a string whose exact
+        from a stored dict - don't store a bare json-object string if you need it
-        value is a json object ('{"a":1}') decrypts to a dict, indistinguishable
+        back as a string.
-        without a type marker from a stored dict — don't store a bare json-object
+
-        string if you need it back as a string. dict keys round-trip faithfully
+        Args:
-        because encrypt_data requires str keys (json's only key type).
+            encrypted_data: a {secure, iv, data} blob from encrypt_data.
+
+        Returns:
+            the original dict or string.
+
+        Raises:
+            ValueError: instance not initialized, or encrypted_data is not a
+                {secure, iv, data} blob.
         """
         if not self.master_key:
             raise ValueError("not initialized with data key")
         if not isinstance(encrypted_data, dict) or "iv" not in encrypted_data or "data" not in encrypted_data:
-            # a structurally-malformed blob would raise a raw KeyError/TypeError; surface
-            # a clear ValueError instead, matching the documented {secure, iv, data} shape
             raise ValueError("decrypt_data expects a {secure, iv, data} blob")
 
         iv = base64.b64decode(encrypted_data["iv"])
@@ -459,22 +449,30 @@ class EnvelopeCrypto:
     def reencrypt(self, source_crypto: "EnvelopeCrypto", record: dict, traversal_level: int = 2) -> dict:
         """re-encrypt a record's encrypted fields from source_crypto's key to this one's
 
-        self holds the destination (new) key; source_crypto holds the source (old) key.
+        self holds the destination (new) key; source_crypto holds the source (old)
-        only {secure, iv, data} fields are touched; plaintext fields are left as-is.
+        key. only {secure, iv, data} fields are touched; plaintext fields are left
-        returns a new dict; the input is not mutated. used during rotation. if `record`
+        as-is. used during rotation. if `record` itself is a bare blob (file-storage
-        itself is a bare blob (file-storage pattern) it is re-encrypted directly and
+        pattern) it is re-encrypted directly and returned in place of `record`.
-        returned in place of `record`, not nested under a key.
 
-        fails loud, unlike decrypt_record: a per-field decrypt failure RAISES (silently
+        traversal recurses into nested DICTS only - a blob nested inside a LIST is
-        keeping a field under the old key would lose it once that key is retired), and
+        not re-encrypted and not covered by the depth-limit raise below; flatten
-        so does a blob nested DEEPER than `traversal_level` — raise a higher
+        list-nested blobs to dict fields before rotation or they'll be silently
-        traversal_level or flatten the record before rotation instead.
+        left under the old key.
 
-        traversal recurses into nested DICTS only; a blob nested inside a LIST is not
+        Args:
-        re-encrypted and not covered by the depth-limit raise. this scheme keys blobs
+            source_crypto: instance holding the old (source) key.
-        by field name, not inside arrays, so this shouldn't arise in practice — but
+            record: the record to re-encrypt. not mutated; a new dict is returned.
-        flatten list-nested blobs to dict fields before rotation or they'll be
+            traversal_level: max nesting depth to recurse into (default 2).
-        silently left under the old key.
+
+        Returns:
+            a new dict with encrypted fields re-wrapped under this instance's key.
+
+        Raises:
+            ValueError: destination not initialized with a data key; a per-field
+                decrypt failure (unlike decrypt_record, this fails loud rather
+                than silently stranding a field under the old key); or a blob
+                nested deeper than `traversal_level` - raise traversal_level or
+                flatten the record before rotation instead.
         """
         if not self.master_key:
             raise ValueError("destination not initialized with data key")
@@ -493,12 +491,12 @@ class EnvelopeCrypto:
                     raise ValueError(
                         f"reencrypt: field {key!r} contains an encrypted blob nested deeper "
                         "than traversal_level; increase traversal_level or flatten the record "
-                        "before rotation — leaving it would strand the field under the old key"
+                        "before rotation - leaving it would strand the field under the old key"
                     )
         return result
 
 
-# naming aliases — same class
+# naming aliases - same class
 DocumentCrypto = EnvelopeCrypto
 RecordCrypto = EnvelopeCrypto
 PCICrypto = EnvelopeCrypto  # deprecated legacy alias; remove after all systems migrate
@@ -507,14 +505,20 @@ PCICrypto = EnvelopeCrypto  # deprecated legacy alias; remove after all systems
 def is_encrypted_record(record, traversal_level: int = 2) -> bool:
     """return whether a record has any encrypted ({secure, iv, data}) fields
 
-    checks `record` itself (the file-storage pattern stores the blob AS the whole
+    checks `record` itself (the file-storage pattern) as well as fields up to
-    document) as well as fields up to `traversal_level` deep. beyond that bounded
+    `traversal_level` deep, then falls back to an unbounded-depth scan - safe to
-    pass, falls back to an unbounded-depth scan, so a blob left behind by a
+    use as a leftover-detecting post-rotation audit; never returns False for a
-    shallower decrypt_record/reencrypt call is still reported — safe to use as a
+    record that still contains a blob, at any depth.
-    leftover-detecting post-rotation audit; never returns False for a record that
-    still contains a blob, at any depth.
 
-    aliases: is_encrypted_document, is_encrypted_dict — same function
+    Args:
+        record: the record (or bare blob) to check.
+        traversal_level: bounded-pass nesting depth before the unbounded
+            fallback scan (default 2).
+
+    Returns:
+        True if record or anything nested under it is an encrypted blob.
+
+    aliases: is_encrypted_document, is_encrypted_dict - same function
     """
     if not isinstance(record, dict):
         return False
@@ -538,12 +542,25 @@ def is_encrypted_record(record, traversal_level: int = 2) -> bool:
 def decrypt_record(crypto: EnvelopeCrypto, record, traversal_level: int = 2) -> Union[dict, Any]:
     """decrypt a record's encrypted fields into a new dict (up to traversal_level deep)
 
-    if `record` itself is a bare {secure, iv, data} blob (file-storage pattern) it is
+    if `record` itself is a bare {secure, iv, data} blob (file-storage pattern) it
-    decrypted directly and the value (dict or string — see decrypt_data) is returned
+    is decrypted directly and the value (dict or string, see decrypt_data) is
-    in place of `record`. a failure on a single field (or on `record` itself) is
+    returned in place of `record`. a failure on a single field (or on `record`
-    logged and left encrypted, so a partial failure stays visible rather than silent.
+    itself) is logged and left encrypted, so a partial failure stays visible
+    rather than silent.
 
-    aliases: decrypt_document, decrypt_dict — same function
+    Args:
+        crypto: instance holding the data key to decrypt with.
+        record: the record (or bare blob) to decrypt. not mutated.
+        traversal_level: max nesting depth to recurse into (default 2).
+
+    Returns:
+        a new dict with encrypted fields decrypted (or record unchanged if not
+        a dict).
+
+    Raises:
+        ValueError: crypto is not initialized with a data key.
+
+    aliases: decrypt_document, decrypt_dict - same function
     """
     if not crypto.master_key:
         raise ValueError("not initialized with data key")
@@ -570,11 +587,7 @@ def decrypt_record(crypto: EnvelopeCrypto, record, traversal_level: int = 2) ->
 
 
 def _fingerprint_default(value: Any) -> str:
-    """json.dumps default= handler for values fingerprint_data can't natively serialize
+    """json.dumps default= handler for values fingerprint_data can't natively serialize"""
-
-    covers datetime/date/time (isoformat), bytes/bytearray (hex), and anything else
-    (e.g. ObjectId) via a type-tagged repr — never raises, never logs the value.
-    """
     if hasattr(value, "isoformat"):
         return f"isoformat:{value.isoformat()}"
     if isinstance(value, (bytes, bytearray)):
@@ -583,13 +596,7 @@ def _fingerprint_default(value: Any) -> str:
 
 
 def _fingerprint_normalize(value: Any) -> Any:
-    """recursively tag dict keys with their type to avoid cross-type key collisions
+    """recursively tag dict keys with their type to avoid cross-type key collisions"""
-
-    json object keys are always strings, so {1: "a"} and {"1": "a"} would otherwise
-    serialize identically and collide to the same fingerprint; prefixing each key with
-    its type name keeps them distinct. non-dict containers/values pass through
-    untouched (lists recurse; leaf values are handled by _fingerprint_default).
-    """
     if isinstance(value, dict):
         return {
             f"{type(key).__name__}:{key!r}": _fingerprint_normalize(sub_value)
@@ -603,18 +610,24 @@ def _fingerprint_normalize(value: Any) -> Any:
 def fingerprint_data(data: dict) -> str:
     """return a deterministic, collision-free SHA-256 hex fingerprint of a dict
 
-    dict keys of different types that would otherwise coerce to the same JSON string
+    dict keys of different types that would otherwise coerce to the same JSON
-    (e.g. {1: "a"} vs {"1": "a"}) are kept distinct via a type-tagged pre-pass. values
+    string (e.g. {1: "a"} vs {"1": "a"}) are kept distinct via a type-tagged
-    that aren't JSON-native (datetime/date/time, bytes/bytearray, ObjectId-like
+    pre-pass. values that aren't JSON-native (datetime/date/time, bytes/bytearray,
-    objects) are serialized via a stable default= handler instead of raising. never
+    ObjectId-like objects) are serialized via a stable default= handler instead of
-    logs the data being fingerprinted.
+    raising. never logs the data being fingerprinted.
+
+    Args:
+        data: the dict to fingerprint.
+
+    Returns:
+        a deterministic SHA-256 hex digest.
     """
     normalized = _fingerprint_normalize(data)
     encoded = json.dumps(normalized, sort_keys=True, default=_fingerprint_default)
     return hashlib.sha256(encoded.encode()).hexdigest()
 
 
-# function aliases — same functions, naming preference only
+# function aliases - same functions, naming preference only
 is_encrypted_document = is_encrypted_record
 is_encrypted_dict = is_encrypted_record
 decrypt_document = decrypt_record