user24926: Let's say I am a node. A transaction has been relayed to me, and one of the scriptSig fields is:
<sig> <pubKey>

What is the easiest way for me to malleate this transaction?

For example, could I just add a "dummy" opcode to it, like this: OP_NOP <sig> <pubKey>?

Also, are certain types of scriptSig easier to malleate than others?

Basically, I'm interested in the most practical way a third party might go about malleating a transaction.

user48884: The easiest way to malleate a transaction is to just change the signature from Low-S to High-S and vice versa.

24926: <p>Let's say I am a node. A transaction has been relayed to me, and one of the <code>scriptSig</code> fields is:</p>

<p><code>&lt;sig&gt; &lt;pubKey&gt;</code></p>

<ol>
<li><p><strong>What is the easiest way for me to malleate this transaction?</strong></p>

<ul>
<li>For example, could I just add a "dummy" opcode to it, like this: <code>OP_NOP &lt;sig&gt; &lt;pubKey&gt;</code>?</li>
</ul></li>
<li><p>Also, are certain types of scriptSig easier to malleate than others?</p></li>
</ol>

<p>Basically, I'm interested in the most practical way a third party might go about malleating a transaction.</p>
 48884: <p>The easiest way to malleate a transaction is to just change the signature from Low-S to High-S and vice versa.</p>
