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Canonical Transaction Ordering

bch
scaling

A Bitcoin Cash rule that orders transactions in a block by transaction ID rather than dependency order.

Also known as
CTOR
1
definition

Canonical Transaction Ordering (CTOR) is a Bitcoin Cash consensus rule requiring transactions within a block to be sorted by transaction ID. This replaced topological ordering, where parent transactions had to appear before children.

2
scaling

CTOR makes block transaction ordering deterministic, which helps with set reconciliation, compact block propagation, and parallel validation research. The benefit is not that CTOR alone scales the network, but that it simplifies other scaling techniques.

3
context

CTOR activated on Bitcoin Cash in November 2018 and was part of a broader debate over BCH scaling direction. It remains a BCH-specific rule and should not be assumed for Bitcoin or other UTXO chains.

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2 linked

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