However, it is not ideal to do that.
It reduces privacy (associates an address) and weakens security (reveals the public key).
It reduces privacy (associates an address) and weakens security (reveals the public key).
revealing the public key as-in exposing the address to a potential future quantum attack, or something more than this?
When you receive bitcoins at an address that has never been used before, there are three levels of cryptography between the private key and the bitcoin address:
- First there is ECDSA with the Secp256k1 curve resulting in a public key.
- Then the public key is hashed with SHA-256.
- Finally the result of the SHA-256 hash is hashed with RIPEMD-160.
It is the result of this RIPEMD-160 hash that is stored in the blockchain and converted to a bitcoin address.
When you send a bitcoin transaction that spends any of the outputs that have been received at an address, the ECDSA public key is included in the transaction.
This means that you then only have 1 level of cryptography between the address and the private key. Since the ECDSA public key becomes publicly available, the protection of SHA-256 and RIPEMD-160 are lost.
From then on, any unspent outputs that remain associated with that address (or any new outputs sent to that address) no longer have the protection of SHA-256 or RIPEMD-160
