Alice and Bob use ScroogeCoin. Alice owns ten coins, each under a different address (public key) and each of value 3.0. She would like to transfer coins of value 5.0 to Bob. Recall that the PayCoins transaction consumes (and destroys) some coins, and creates new coins of the same total value. Alice’s transfer will require, at a minimum: (check all that apply)
Two PayCoins transactions, two new coins created, and four signatures
One PayCoins transaction, two new coins created, and two signatures (This is correct- see below)
Two PayCoins transactions, one new coin created, and two signatures
One PayCoins transaction, one new coin created, and one signature
Conceptually, this is one transaction. In one transaction, multiple addresses can be used, but for each address, we need a signature. In terms of coin. coins are only created or destroyed, never changed (including changing owner), so the two coins by Alice has to be destroyed, and we create one 5.0 coin for Bob, and one 1.0 coin for Alice as change.
I got this wrong the first time. I thought a transaction can involve only two addresses, apparently I am wrong.
Two PayCoins transactions, two new coins created, and four signatures
One PayCoins transaction, two new coins created, and two signatures (This is correct- see below)
Two PayCoins transactions, one new coin created, and two signatures
One PayCoins transaction, one new coin created, and one signature
Conceptually, this is one transaction. In one transaction, multiple addresses can be used, but for each address, we need a signature. In terms of coin. coins are only created or destroyed, never changed (including changing owner), so the two coins by Alice has to be destroyed, and we create one 5.0 coin for Bob, and one 1.0 coin for Alice as change.
I got this wrong the first time. I thought a transaction can involve only two addresses, apparently I am wrong.
But why two signatures? That confuses me. The signatures of the owners only are required and the owner of the two coins being spent is the same person. So, logically only one signature should be required...
ReplyDeleteBut because the owner is sending it to two different addresses (one of which is his/her own), therefore he will have to sign one for each address
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