CTOR, Huh? Yeah! What Is It Good For?
September 16, 2018 by Paul de Havilland
With the implementation of CTOR into the BCH protocol via Bitcoin ABC slated for inclusion in the November 2018 upgrade, the bitcoin cash community has witnessed something of a division over its advantages and risks. So what is CTOR, or “Canonical Transaction Ordering Rule”? Let’s take a look.
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Canonical Transaction Ordering Rule – What Could Possibly Go Wrong?
CoinGeek and nChain have both argued that the forthcoming changes, including CTOR, are unnecessary as they fail to substantially increase scaling or speed. The nChain/CoinGeek stance is that replacing BCH’s Topological Transaction Ordering Rule (TTOR) with a Canonical Transaction Ordering Rule (CTOR) is unnecessary because TTOR appears to pose little threat to BCH scalability, and risky because not enough research has been undertaken to prove it is safe.
CoinGeek and nChain are planning to create and support “Bitcoin SV” (named after “Satoshi’s Vision”), which would be intended to resist what they call unnecessary additions to the protocol.
Conversely, Bitcoin ABC, the protocol software currently used by a majority of BCH miners and nodes, have outlined a number of benefits of CTOR over TTOR. In a Medium blog post of August 15th, the group argued for the simplicity and elegance of CTOR over TTOR.
Jonald Fyookball Op-ed on CTOR
Bitcoin Cash app developer Jonald Fyookball has also expressed his support in an op-ed piece, arguing that CTOR brings a number of benefits, including simplifying parallel processing for block validation by “removing the topological ordering requirement”. He also stresses the benefits to block propagation, pointedly spelling out that:
“The most obvious application for CTOR today is that it helps Graphene work better… a unique ordering helps propagation [because] you can save bandwidth if you only have to transmit data for missing transactions without communicating anything about the order of the transactions in a block. Thus, a canonical ordering can help other block propagation schemes such as Xthin; its benefits are not just limited to Graphene.”
The new canonical structure places transactions in numerical order from lowest to highest. Doing so makes the need to be faithful to topographical ordering unnecessary (and in fact impossible). If the block is valid, transaction ordering within the block is irrelevant, (or far less important than the order of blocks). The benefit for the BCH network is scaling.
This change is not as radical as some try to suggest, wrote Fyookball. In fact it’s necessary for BCH’s “huge blocks” (up to 128 MB after Bitcoin ABC’s proposed update in November 2018) and on-chain scaling. CTOR is a software optimization process, he said, making sure transactions are recorded in the correct order they happened, removing the need to check a whole block for validity. This would, in turn, allow for faster transaction confirmations.
It is also important to note that nChain had once appeared to support the change before — John Kerry/Iraq War style — ultimately voting against it.
Sound off below. Are you a CTOR advocate or perfectly happy with TTOR?
Images via Pixabay
