Taproot
A Bitcoin upgrade introducing bc1p addresses and Schnorr signatures. Taproot key-path spends place a public key in the output, so a funded Taproot address exposes a key earlier than a comparable P2PKH address.
Related terms
A Bitcoin upgrade that moves signature data outside the transaction body, enabling lower fees and address types beginning with bc1q. From a quantum standpoint SegWit behaves like P2PKH — the public key appears on first spend.
Whether an address's full public key is visible on-chain. Exposure matters because quantum risk to a wallet begins only once the public key is published — before that, an attacker sees just a hash.
The legacy Bitcoin address type beginning with 1, which locks funds to the hash of a public key rather than the key itself. An unspent P2PKH output does not reveal its public key.