Authentication

Low-level authentication functions for the Icom LAN protocol. These are used internally by IcomRadio.

Credential Encoding

encode_credentials()

def encode_credentials(text: str) -> bytes

Encode a username or password using Icom's position-dependent substitution table. Maximum 16 characters.

Not Encryption

This is a simple obfuscation scheme, not cryptographic encryption. The substitution table is publicly known. See Security.

Packet Builders

build_login_packet()

def build_login_packet(
    username: str,
    password: str,
    *,
    sender_id: int,
    receiver_id: int,
    tok_request: int = 0,
    auth_seq: int = 0,
    computer_name: str = "icom-lan",
) -> bytes

Build a 0x80-byte login packet with encoded credentials.

build_conninfo_packet()

def build_conninfo_packet(
    *,
    sender_id: int,
    receiver_id: int,
    username: str,
    token: int,
    tok_request: int,
    radio_name: str,
    mac_address: bytes,
    auth_seq: int = 0,
    rx_codec: int = 0x04,
    tx_codec: int = 0x04,
    rx_sample_rate: int = 48000,
    tx_sample_rate: int = 48000,
    civ_local_port: int = 0,
    audio_local_port: int = 0,
    tx_buffer: int = 150,
    guid: bytes | None = None,
) -> bytes

Build a 0x90-byte connection info / stream request packet. Includes audio codec preferences and the radio's GUID (must be echoed from the radio's conninfo).

Response Parsers

parse_auth_response()

def parse_auth_response(data: bytes) -> AuthResponse

Parse a 0x60-byte login response.

AuthResponse

Field	Type	Description
success	bool	Whether authentication succeeded
token	int	Session token (4 bytes)
tok_request	int	Token request ID
connection_type	str	Connection type string (e.g., "FTTH")
error	int	Raw error code (0 = success)

parse_status_response()

def parse_status_response(data: bytes) -> StatusResponse

Parse a 0x50-byte status packet.

StatusResponse

Field	Type	Description
civ_port	int	CI-V data port number
audio_port	int	Audio stream port number
error	int	Error code (0 = OK)
disconnected	bool	Whether radio signaled disconnect

Substitution Table

The PASSCODE_SEQUENCE table (128 bytes) is derived from wfview's reverse engineering of Icom's credential obfuscation. Each character is mapped based on its position:

index = (ascii_value + position) % 127
if index < 32:
    index += 32  # Stay in printable range
encoded_byte = PASSCODE_SEQUENCE[index]

This table is identical across all Icom radios that support LAN control.