check_has_key

Check if an address has a registered viewing key

Public, read-only queries against the Directory contract. No authentication required — works with a standard Web3 instance.

Signatures

# check_has_key
def check_has_key(w3: Web3, address: ChecksumAddress) -> bool
async def async_check_has_key(w3: AsyncWeb3, address: ChecksumAddress) -> bool

# get_key_hash
def get_key_hash(w3: Web3, address: ChecksumAddress) -> bytes
async def async_get_key_hash(w3: AsyncWeb3, address: ChecksumAddress) -> bytes

Parameters

Parameter	Type	Description
w3	Web3 / AsyncWeb3	Standard Web3 instance (no Seismic namespace required)
address	ChecksumAddress	Address to query

Returns

• check_has_key — True if the address has a registered viewing key

• get_key_hash — 32-byte keccak256 hash of the viewing key (zero bytes if no key registered)

Example

from web3 import Web3
from seismic_web3.src20 import check_has_key, get_key_hash

w3 = Web3(Web3.HTTPProvider("https://gcp-1.seismictest.net/rpc"))
address = "0xf39Fd6e51aad88F6F4ce6aB8827279cffFb92266"

if check_has_key(w3, address):
    key_hash = get_key_hash(w3, address)
    print(f"Key hash: {key_hash.hex()}")

Notes

• Both use plain eth_call — no gas cost, no encryption needed

• The key hash is used as the 4th topic in SRC20 Transfer and Approval events for filtering

See Also

• register_viewing_key — Register a viewing key

• get_viewing_key — Fetch your viewing key (authenticated)