api: add BTCXpubsRequest to fetch multiple xpubs at once

To reduce the number of secure chip operations needed, we introduce a
new API call to fetch multiple xpubs at once. This only requires two
operations in total, instead of two per xpub.

We want to reduce the number of secure chip operations to avoid
running into Optiga's throttling security measure.

Author: benma

CHANGELOG.md

@@ -12,6 +12,7 @@ customers cannot upgrade their bootloader, its changes are recorded separately.
 - Remove option to restore from 18 recovery words
 - simulator: enable Test Merchant for payment requests
 - simulator: simulate a Nova device
+- Add API call to fetch multiple xpubs at once
 
 ### 9.23.1
 - EVM: add HyperEVM (HYPE) and SONIC (S) to known networks

messages/btc.proto

@@ -93,6 +93,17 @@ message BTCPubRequest {
   bool display = 5;
 }
 
+message BTCXpubsRequest{
+  enum XPubType {
+    UNKNOWN = 0;
+    XPUB = 1;
+    TPUB = 2;
+  }
+  BTCCoin coin = 1;
+  XPubType xpub_type = 2;
+  repeated Keypath keypaths = 3;
+}
+
 message BTCScriptConfigWithKeypath {
   BTCScriptConfig script_config = 2;
   repeated uint32 keypath = 3;
@@ -281,6 +292,7 @@ message BTCRequest {
     BTCSignMessageRequest sign_message = 6;
     AntiKleptoSignatureRequest antiklepto_signature = 7;
     BTCPaymentRequestRequest payment_request = 8;
+    BTCXpubsRequest xpubs = 9;
   }
 }
 
@@ -291,5 +303,6 @@ message BTCResponse {
     BTCSignNextResponse sign_next = 3;
     BTCSignMessageResponse sign_message = 4;
     AntiKleptoSignerCommitment antiklepto_signer_commitment = 5;
+    PubsResponse pubs = 6;
   }
 }

messages/common.proto

@@ -19,6 +19,10 @@ message PubResponse {
   string pub = 1;
 }
 
+message PubsResponse {
+  repeated string pubs = 1;
+}
+
 message RootFingerprintRequest {
 }
 

py/bitbox02/bitbox02/bitbox02/bitbox02.py

@@ -320,6 +320,26 @@ def btc_xpub(
         )
         return self._msg_query(request).pub.pub
 
+    def btc_xpubs(
+        self,
+        keypaths: Sequence[Sequence[int]],
+        coin: "btc.BTCCoin.V" = btc.BTC,
+        xpub_type: "btc.BTCXpubsRequest.XPubType.V" = btc.BTCXpubsRequest.XPUB,
+    ) -> List[str]:
+        """
+        Retrieve up to 20 xpubs.
+        """
+        self._require_atleast(semver.VersionInfo(9, 24, 0))
+        btc_request = btc.BTCRequest()
+        btc_request.xpubs.CopyFrom(
+            btc.BTCXpubsRequest(
+                coin=coin,
+                keypaths=[common.Keypath(keypath=keypath) for keypath in keypaths],
+                xpub_type=xpub_type,
+            )
+        )
+        return list(self._btc_msg_query(btc_request, expected_response="pubs").pubs.pubs)
+
     def btc_address(
         self,
         keypath: Sequence[int],

py/bitbox02/bitbox02/communication/generated/bitbox02_system_pb2.pyi

@@ -79,7 +79,7 @@ class DeviceInfoResponse(google.protobuf.message.Message):
         firmware_hash: builtins.bytes
         """Hash of the currently active Bluetooth firmware on the device."""
         firmware_version: builtins.str
-        """Firmware version, formated as "major.minor.patch"."""
+        """Firmware version, formated as an unsigned integer "1", "2", etc."""
         enabled: builtins.bool
         """True if Bluetooth is enabled"""
         def __init__(

py/bitbox02/bitbox02/communication/generated/btc_pb2.py

@@ -263,6 +263,43 @@ class BTCPubRequest(google.protobuf.message.Message):
 
 global___BTCPubRequest = BTCPubRequest
 
+@typing.final
+class BTCXpubsRequest(google.protobuf.message.Message):
+    DESCRIPTOR: google.protobuf.descriptor.Descriptor
+
+    class _XPubType:
+        ValueType = typing.NewType("ValueType", builtins.int)
+        V: typing_extensions.TypeAlias = ValueType
+
+    class _XPubTypeEnumTypeWrapper(google.protobuf.internal.enum_type_wrapper._EnumTypeWrapper[BTCXpubsRequest._XPubType.ValueType], builtins.type):
+        DESCRIPTOR: google.protobuf.descriptor.EnumDescriptor
+        UNKNOWN: BTCXpubsRequest._XPubType.ValueType  # 0
+        XPUB: BTCXpubsRequest._XPubType.ValueType  # 1
+        TPUB: BTCXpubsRequest._XPubType.ValueType  # 2
+
+    class XPubType(_XPubType, metaclass=_XPubTypeEnumTypeWrapper): ...
+    UNKNOWN: BTCXpubsRequest.XPubType.ValueType  # 0
+    XPUB: BTCXpubsRequest.XPubType.ValueType  # 1
+    TPUB: BTCXpubsRequest.XPubType.ValueType  # 2
+
+    COIN_FIELD_NUMBER: builtins.int
+    XPUB_TYPE_FIELD_NUMBER: builtins.int
+    KEYPATHS_FIELD_NUMBER: builtins.int
+    coin: global___BTCCoin.ValueType
+    xpub_type: global___BTCXpubsRequest.XPubType.ValueType
+    @property
+    def keypaths(self) -> google.protobuf.internal.containers.RepeatedCompositeFieldContainer[common_pb2.Keypath]: ...
+    def __init__(
+        self,
+        *,
+        coin: global___BTCCoin.ValueType = ...,
+        xpub_type: global___BTCXpubsRequest.XPubType.ValueType = ...,
+        keypaths: collections.abc.Iterable[common_pb2.Keypath] | None = ...,
+    ) -> None: ...
+    def ClearField(self, field_name: typing.Literal["coin", b"coin", "keypaths", b"keypaths", "xpub_type", b"xpub_type"]) -> None: ...
+
+global___BTCXpubsRequest = BTCXpubsRequest
+
 @typing.final
 class BTCScriptConfigWithKeypath(google.protobuf.message.Message):
     DESCRIPTOR: google.protobuf.descriptor.Descriptor
@@ -826,6 +863,7 @@ class BTCRequest(google.protobuf.message.Message):
     SIGN_MESSAGE_FIELD_NUMBER: builtins.int
     ANTIKLEPTO_SIGNATURE_FIELD_NUMBER: builtins.int
     PAYMENT_REQUEST_FIELD_NUMBER: builtins.int
+    XPUBS_FIELD_NUMBER: builtins.int
     @property
     def is_script_config_registered(self) -> global___BTCIsScriptConfigRegisteredRequest: ...
     @property
@@ -842,6 +880,8 @@ class BTCRequest(google.protobuf.message.Message):
     def antiklepto_signature(self) -> antiklepto_pb2.AntiKleptoSignatureRequest: ...
     @property
     def payment_request(self) -> global___BTCPaymentRequestRequest: ...
+    @property
+    def xpubs(self) -> global___BTCXpubsRequest: ...
     def __init__(
         self,
         *,
@@ -853,10 +893,11 @@ class BTCRequest(google.protobuf.message.Message):
         sign_message: global___BTCSignMessageRequest | None = ...,
         antiklepto_signature: antiklepto_pb2.AntiKleptoSignatureRequest | None = ...,
         payment_request: global___BTCPaymentRequestRequest | None = ...,
+        xpubs: global___BTCXpubsRequest | None = ...,
     ) -> None: ...
-    def HasField(self, field_name: typing.Literal["antiklepto_signature", b"antiklepto_signature", "is_script_config_registered", b"is_script_config_registered", "payment_request", b"payment_request", "prevtx_init", b"prevtx_init", "prevtx_input", b"prevtx_input", "prevtx_output", b"prevtx_output", "register_script_config", b"register_script_config", "request", b"request", "sign_message", b"sign_message"]) -> builtins.bool: ...
-    def ClearField(self, field_name: typing.Literal["antiklepto_signature", b"antiklepto_signature", "is_script_config_registered", b"is_script_config_registered", "payment_request", b"payment_request", "prevtx_init", b"prevtx_init", "prevtx_input", b"prevtx_input", "prevtx_output", b"prevtx_output", "register_script_config", b"register_script_config", "request", b"request", "sign_message", b"sign_message"]) -> None: ...
-    def WhichOneof(self, oneof_group: typing.Literal["request", b"request"]) -> typing.Literal["is_script_config_registered", "register_script_config", "prevtx_init", "prevtx_input", "prevtx_output", "sign_message", "antiklepto_signature", "payment_request"] | None: ...
+    def HasField(self, field_name: typing.Literal["antiklepto_signature", b"antiklepto_signature", "is_script_config_registered", b"is_script_config_registered", "payment_request", b"payment_request", "prevtx_init", b"prevtx_init", "prevtx_input", b"prevtx_input", "prevtx_output", b"prevtx_output", "register_script_config", b"register_script_config", "request", b"request", "sign_message", b"sign_message", "xpubs", b"xpubs"]) -> builtins.bool: ...
+    def ClearField(self, field_name: typing.Literal["antiklepto_signature", b"antiklepto_signature", "is_script_config_registered", b"is_script_config_registered", "payment_request", b"payment_request", "prevtx_init", b"prevtx_init", "prevtx_input", b"prevtx_input", "prevtx_output", b"prevtx_output", "register_script_config", b"register_script_config", "request", b"request", "sign_message", b"sign_message", "xpubs", b"xpubs"]) -> None: ...
+    def WhichOneof(self, oneof_group: typing.Literal["request", b"request"]) -> typing.Literal["is_script_config_registered", "register_script_config", "prevtx_init", "prevtx_input", "prevtx_output", "sign_message", "antiklepto_signature", "payment_request", "xpubs"] | None: ...
 
 global___BTCRequest = BTCRequest
 
@@ -869,6 +910,7 @@ class BTCResponse(google.protobuf.message.Message):
     SIGN_NEXT_FIELD_NUMBER: builtins.int
     SIGN_MESSAGE_FIELD_NUMBER: builtins.int
     ANTIKLEPTO_SIGNER_COMMITMENT_FIELD_NUMBER: builtins.int
+    PUBS_FIELD_NUMBER: builtins.int
     @property
     def success(self) -> global___BTCSuccess: ...
     @property
@@ -879,6 +921,8 @@ class BTCResponse(google.protobuf.message.Message):
     def sign_message(self) -> global___BTCSignMessageResponse: ...
     @property
     def antiklepto_signer_commitment(self) -> antiklepto_pb2.AntiKleptoSignerCommitment: ...
+    @property
+    def pubs(self) -> common_pb2.PubsResponse: ...
     def __init__(
         self,
         *,
@@ -887,9 +931,10 @@ class BTCResponse(google.protobuf.message.Message):
         sign_next: global___BTCSignNextResponse | None = ...,
         sign_message: global___BTCSignMessageResponse | None = ...,
         antiklepto_signer_commitment: antiklepto_pb2.AntiKleptoSignerCommitment | None = ...,
+        pubs: common_pb2.PubsResponse | None = ...,
     ) -> None: ...
-    def HasField(self, field_name: typing.Literal["antiklepto_signer_commitment", b"antiklepto_signer_commitment", "is_script_config_registered", b"is_script_config_registered", "response", b"response", "sign_message", b"sign_message", "sign_next", b"sign_next", "success", b"success"]) -> builtins.bool: ...
-    def ClearField(self, field_name: typing.Literal["antiklepto_signer_commitment", b"antiklepto_signer_commitment", "is_script_config_registered", b"is_script_config_registered", "response", b"response", "sign_message", b"sign_message", "sign_next", b"sign_next", "success", b"success"]) -> None: ...
-    def WhichOneof(self, oneof_group: typing.Literal["response", b"response"]) -> typing.Literal["success", "is_script_config_registered", "sign_next", "sign_message", "antiklepto_signer_commitment"] | None: ...
+    def HasField(self, field_name: typing.Literal["antiklepto_signer_commitment", b"antiklepto_signer_commitment", "is_script_config_registered", b"is_script_config_registered", "pubs", b"pubs", "response", b"response", "sign_message", b"sign_message", "sign_next", b"sign_next", "success", b"success"]) -> builtins.bool: ...
+    def ClearField(self, field_name: typing.Literal["antiklepto_signer_commitment", b"antiklepto_signer_commitment", "is_script_config_registered", b"is_script_config_registered", "pubs", b"pubs", "response", b"response", "sign_message", b"sign_message", "sign_next", b"sign_next", "success", b"success"]) -> None: ...
+    def WhichOneof(self, oneof_group: typing.Literal["response", b"response"]) -> typing.Literal["success", "is_script_config_registered", "sign_next", "sign_message", "antiklepto_signer_commitment", "pubs"] | None: ...
 
 global___BTCResponse = BTCResponse

py/bitbox02/bitbox02/communication/generated/btc_pb2.pyi

@@ -40,6 +40,22 @@ class PubResponse(google.protobuf.message.Message):
 
 global___PubResponse = PubResponse
 
+@typing.final
+class PubsResponse(google.protobuf.message.Message):
+    DESCRIPTOR: google.protobuf.descriptor.Descriptor
+
+    PUBS_FIELD_NUMBER: builtins.int
+    @property
+    def pubs(self) -> google.protobuf.internal.containers.RepeatedScalarFieldContainer[builtins.str]: ...
+    def __init__(
+        self,
+        *,
+        pubs: collections.abc.Iterable[builtins.str] | None = ...,
+    ) -> None: ...
+    def ClearField(self, field_name: typing.Literal["pubs", b"pubs"]) -> None: ...
+
+global___PubsResponse = PubsResponse
+
 @typing.final
 class RootFingerprintRequest(google.protobuf.message.Message):
     DESCRIPTOR: google.protobuf.descriptor.Descriptor

py/bitbox02/bitbox02/communication/generated/common_pb2.py

@@ -331,6 +331,14 @@ def _display_zpub(self) -> None:
         except UserAbortException:
             eprint("Aborted by user")
 
+    def _btc_xpubs(self) -> None:
+        xpubs = self._device.btc_xpubs(
+            keypaths=[[84 + HARDENED, 0 + HARDENED, i + HARDENED] for i in range(20)],
+        )
+        print("xpubs for m/84'/0'/{0'..19'}:")
+        for xpub in xpubs:
+            print(xpub)
+
     def _get_electrum_encryption_key(self) -> None:
         print(
             "Electrum wallet encryption xpub at keypath m/4541509'/1112098098':",
@@ -376,7 +384,7 @@ def _btc_multisig_config(self, coin: "bitbox02.btc.BTCCoin.V") -> bitbox02.btc.B
         my_xpub = self._device.btc_xpub(
             keypath=account_keypath,
             coin=coin,
-            xpub_type=bitbox02.btc.BTCPubRequest.XPUB,  # pylint: disable=no-member,
+            xpub_type=bitbox02.btc.BTCPubRequest.XPUB,
             display=False,
         )
         multisig_config = bitbox02.btc.BTCScriptConfig(
@@ -1503,6 +1511,7 @@ def _menu_init(self) -> None:
             ("Change device name", self._change_name_workflow),
             ("Get root fingerprint", self._get_root_fingerprint),
             ("Retrieve zpub of first account", self._display_zpub),
+            ("Retrieve multiple xpubs", self._btc_xpubs),
             ("Retrieve a BTC address", self._btc_address),
             ("Retrieve a BTC Multisig address", self._btc_multisig_address),
             ("Retrieve a BTC policy address", self._btc_policy_address),