From https://en.bitcoin.it/wiki/Address:

A Bitcoin address, or simply address, is an identifier of 27-34 alphanumeric characters, beginning with the number 1 or 3, that represents a possible destination for a Bitcoin payment

Why "a possible"? Isn't always an address a destination? Is always based on the ScriptPubkey of the Tx output.

2 Answers 2


I believe it's just saying "possible" because a created address may never end up being sent to; in fact, it might never be shared with a payer at all.

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    I was thinking it could be referring to change addresses, but your explanation sounds more likely. Commented Oct 28, 2022 at 16:52
  • I have found that it's confusing for newcomers to understand that addresses represent the actual ScriptPubkey of an output. Doing some research, I have found that no address definition mentions this to clarify it. Is there a reason for it? Commented Oct 28, 2022 at 17:17
  • The definition for address I use is that it's a template to construct scriptPubKeys with. Whether someone actually puts that scriptPubKey in a transaction that actually makes it to the chain isn't relevant. Commented Oct 28, 2022 at 17:36
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    That's currently mostly true, but with two caveats: (1) not all valid scriptPubKeys have a corresponding address and (2) something like the proposed silent payment addresses and its predecessors are one-way: the receiver can go from address to many scriptPubKeys, but someone who only sees the scriptPubKey cannot find out what its address was (or find out whether two scriptPubKeys were created from the same address). I think the only correct thing to say is that an address is an encoding of instructions for a sender to construct a scriptPubKey with, given these facts. Commented Oct 28, 2022 at 18:19
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    For an example an OP_RETURN output, which is unspendable. No address exists for such an output, because you can't send money to it. But there are protocols/use cases that involve adding such outputs to transactions. Before P2SH existed, multisig was possible by putting a multisig script directly in the scriptPubKey, but there was never a way of conveying such a script to a sender in the form of an address. Commented Oct 28, 2022 at 18:54

It's a possible destination, "a" indicating a singular destination. As in one possible destination; there exist many addresses and so many possible destinations.

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