Add functions/tool for gen/verifying BLE IRK/RPA

apps/ble_rpa_tool.py

@@ -0,0 +1,63 @@
+# Copyright 2023 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import click
+from bumble.colors import color
+from bumble.hci import Address
+from bumble.helpers import generate_irk, generate_rpa_with_irk, verify_rpa_with_irk
+
+
+@click.group()
+def cli():
+    '''
+    This is a tool for generating IRK, RPA,
+    and verifying IRK/RPA pairs
+    '''
+
+
+@click.command()
+def gen_irk() -> None:
+    print(generate_irk().hex())
+
+
+@click.command()
+@click.argument("irk", type=str)
+def gen_rpa(irk: str) -> None:
+    irk_bytes = bytes.fromhex(irk)
+    rpa = generate_rpa_with_irk(irk_bytes)
+    print(rpa.to_string(with_type_qualifier=False))
+
+
+@click.command()
+@click.argument("irk", type=str)
+@click.argument("rpa", type=str)
+def verify_rpa(irk: str, rpa: str) -> None:
+    address = Address(rpa)
+    irk_bytes = bytes.fromhex(irk)
+    if verify_rpa_with_irk(address, irk_bytes):
+        print(color("Verified", "green"))
+    else:
+        print(color("Not Verified", "red"))
+
+
+def main():
+    cli.add_command(gen_irk)
+    cli.add_command(gen_rpa)
+    cli.add_command(verify_rpa)
+    cli()
+
+
+# -----------------------------------------------------------------------------
+if __name__ == '__main__':
+    main()

bumble/helpers.py

@@ -37,6 +37,7 @@
     L2CAP_Connection_Response,
 )
 from bumble.hci import (
+    Address,
     HCI_EVENT_PACKET,
     HCI_ACL_DATA_PACKET,
     HCI_DISCONNECTION_COMPLETE_EVENT,
@@ -48,6 +49,7 @@
 )
 from bumble.rfcomm import RFCOMM_Frame, RFCOMM_PSM
 from bumble.sdp import SDP_PDU, SDP_PSM
+from bumble import crypto
 
 # -----------------------------------------------------------------------------
 # Logging
@@ -232,3 +234,28 @@ def __init__(
         )
         self.host_to_controller_analyzer.peer = self.controller_to_host_analyzer
         self.controller_to_host_analyzer.peer = self.host_to_controller_analyzer
+
+
+def generate_irk() -> bytes:
+    return crypto.r()
+
+
+def generate_rpa_with_irk(irk: bytes) -> Address:
+    if len(irk) != 16:
+        raise ValueError("IRK should be 16 bytes")
+
+    prand_ = list(crypto.r()[:3])
+    prand_[2] &= 0x7F  # set the 8th bit to 0
+    prand_[2] |= 0x40  # set the 7th bit to 1
+    prand = bytes(prand_)
+    hash_computed = crypto.ah(irk, prand)
+    address_bytes = hash_computed[:3] + prand
+    return Address(address=address_bytes, address_type=Address.RANDOM_DEVICE_ADDRESS)
+
+
+def verify_rpa_with_irk(rpa: Address, irk: bytes) -> bool:
+    rpa_bytes = bytes(rpa)
+    prand_given = rpa_bytes[3:]
+    hash_given = rpa_bytes[:3]
+    hash_local = crypto.ah(irk, prand_given)
+    return hash_local[:3] == hash_given

setup.cfg

@@ -56,6 +56,7 @@ install_requires =
 
 [options.entry_points]
 console_scripts =
+    bumble-ble-rpa-tool = bumble.apps.ble_rpa_tool:main
     bumble-console = bumble.apps.console:main
     bumble-controller-info = bumble.apps.controller_info:main
     bumble-gatt-dump = bumble.apps.gatt_dump:main