public key – Are there 2^160 attainable addresses or 4*2^160 (4 tackle varieties) attainable addresses?

There are literally 5 tackle varieties generally in use for the time being (P2PKH, P2SH, P2WPKH, P2WSH, and P2TR), and two of them encode a 32-byte (256-bit) worth, not a 20-byte (160-bit) one, so the precise variety of attainable addresses is 2*2^256 + 3*2^160.

You technically can convert between some tackle varieties, for instance each P2PKH and P2WPKH encode the identical sort of public key hash. Nonetheless, you must by no means do that, as a result of 1) the recepient will virtually definitely not monitor the blockchain for funds to the transformed tackle, and a pair of) they may not even be capable of spend cash despatched to the transformed tackle, for instance if their non-public secret’s on a {hardware} safety module that solely works for his or her unique tackle sort. All the time ship to the precise tackle you’re given.

There are literally 5 tackle varieties generally in use for the time being (P2PKH, P2SH, P2WPKH, P2WSH, and P2TR), and two of them encode a 32-byte (256-bit) worth, not a 20-byte (160-bit) one, so the precise variety of attainable addresses is 2*2^256 + 3*2^160.

You technically can convert between some tackle varieties, for instance each P2PKH and P2WPKH encode the identical sort of public key hash. Nonetheless, you must by no means do that, as a result of 1) the recepient will virtually definitely not monitor the blockchain for funds to the transformed tackle, and a pair of) they may not even be capable of spend cash despatched to the transformed tackle, for instance if their non-public secret’s on a {hardware} safety module that solely works for his or her unique tackle sort. All the time ship to the precise tackle you’re given.