user6004: In the (e)UTxO model, discussed in the 1st lecture of PPP#3, I am trying to understand the differences between the UTxO model of Bitcoin and the (e)UTxO model of Cardano.
From what I understand, the "script" in Cardano is similar to the locking script (ScriptPubKey) used in Bitcoin, and "redeemer" is similar to the unlocking script (ScriptSig). The main difference being that Cardano script is Turing Complete. Is this a correct assumption ?
And what is the new "Datum" used in Cardano and how large is it ? I assume that "Datum" is stored "on-chain"?

user4469: One way to think of it is that:

The Datum is a piece of data that's attached to the UTXO by the producer,
The Redeemer is a piece of data that's provided by the consumer,
When the UTXO is consumed, the script is run with both the Datum and the Redeemer as arguments and it can thus verify its spent in the right context.

The Datum can be "arbitrarily" large subject to the Tx size limits. What's get stored in the UTXO is actually not the Datum itself but its hash. The spending transaction has to provide the actual Datum, of course matching the hashes stored in the UTXO.
I think your analogy is correct but I am not knowledgeable enough with Bitcoin to be sure.
HTH.

6004: <p>In the (e)UTxO model, discussed in the 1st lecture of PPP#3, I am trying to understand the differences between the UTxO model of Bitcoin and the (e)UTxO model of Cardano.</p>
<p>From what I understand, the &quot;script&quot; in Cardano is similar to the locking script (ScriptPubKey) used in Bitcoin, and &quot;redeemer&quot; is similar to the unlocking script (ScriptSig). The main difference being that Cardano script is Turing Complete. Is this a correct assumption ?</p>
<p>And what is the new &quot;Datum&quot; used in Cardano and how large is it ? I assume that &quot;Datum&quot; is stored &quot;on-chain&quot;?</p>
 4469: <p>One way to think of it is that:</p>
<ul>
<li>The <code>Datum</code> is a piece of data that's attached to the UTXO by the producer,</li>
<li>The <code>Redeemer</code> is a piece of data that's provided by the consumer,</li>
<li>When the UTXO is consumed, the script is run with both the <code>Datum</code> and the <code>Redeemer</code> as arguments and it can thus verify its spent in the right context.</li>
</ul>
<p>The <code>Datum</code> can be &quot;arbitrarily&quot; large subject to the Tx size limits. What's get stored in the UTXO is actually not the <code>Datum</code> itself but its hash. The spending transaction has to provide the actual <code>Datum</code>, of course matching the hashes stored in the UTXO.</p>
<p>I think your analogy is correct but I am not knowledgeable enough with Bitcoin to be sure.</p>
<p>HTH.</p>
