Statistics from the 2015 malleability attack on Bitcoin.

The red lines roughly represent malleated transactions on the network This doesn’t need to be a big problem in itself.

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But now, the two were making progress with their ideas to counter malleability.

“I'm talking about making the [entirety] of the scriptsig largely [separate],” Maxwell wrote.

But despite initial excitement, Segregated Witness had its critics, too.

Concerns about the proposed protocol upgrade varied.

This, in turn, makes it significantly harder to build certain second-layer protocols on top of Bitcoin, like bi-directional payment channels.

The general idea to solve the malleability bug by “separating” signature data from other transaction data stems back several years.

This feature would conclusively solve the malleability issue on the sidechain — by separating base transaction data from witness data into different data structures.

The name of this new feature was, of course, Segregated Witness.

No easy task — even more so because there was no community-wide consensus for this change.

Regardless, by the summer of 2015, Andresen and Hearn announced that they would move forward with their plans, using the alternative Bitcoin XT software client.

“I'd even suggest using as [transaction ID] the transaction without the scriptsigs.”Another month later, Maxwell and, this time, well-known cryptographer Dr.