Smart Contract Blacklist Functions Explained

USDT — addBlackList(address): the ban switch. Callable only by the contract owner (Tether). It sets an internal isBlackListed flag on the target address. After it lands, any transfer that involves that address reverts, so the wallet can neither send nor receive USDT. On TRON and Ethereum this is the exact call that "freezes" a wallet.

USDT — removeBlackList(address): the un-ban. Clears the isBlackListed flag so the address can transact again. It is rare — the vast majority of bans are never lifted — which is why an un-ban event is notable.

USDT — destroyBlackFunds(address): the burn. After an address is blacklisted, Tether can wipe its entire USDT balance to zero and reduce total supply by the same amount. This is how frozen funds are permanently removed rather than merely locked. Every destroyBlackFunds call is public and irreversible.

USDT — isBlackListed(address): the read-only status check. Anyone can call it to see whether an address is currently banned. Our checker reads this state for you against the live contract, so you never have to query the chain by hand.

USDC — blacklist(address) / unBlacklist(address): Circle's equivalents. USDC guards these behind a dedicated blacklister role rather than a single owner, and exposes isBlacklisted(address) to read the state. Blacklisted USDC cannot be moved; Circle can also mint/burn under separate roles.

Why it matters: these functions mean stablecoins are not censorship-resistant — the issuer can freeze or destroy a balance at will, on-chain and without warning. Exchanges, OTC desks and merchants screen incoming addresses against these flags to avoid receiving soon-to-be-frozen funds. Checking an address before you accept a payment is the single cheapest way to avoid a frozen balance.