How can one get the corresponding public key of a Bitcoin address?

[lijunbc]

When someone send payment from address A to address B,

1. Will the transaction information includes publicKey for address A and be signed by the corresponding private Key?
2. Can transaction info include something secret for the receipt, that is, encrypted by the publicKey of address B?

My puzzle is that since the public key cannot derived from the address (hashing is irreversible), how one can find the corresponding public key for an address?

Thanks,

[DannyHamilton]

When someone send payment from address A to address B,

1. Will the transaction information includes publicKey for address A and be signed by the corresponding private Key?

Yes. This is how bitcoin works.

2. Can transaction info include something secret for the receipt, that is, encrypted by the publicKey of address B?

The sender does not have the public key of address B. I suppose if the owner of address B supplies you with their public key, then this would be possible.