Large Transaction Vulnerability

[tynes]

All L2 transactions must be able to be included in a batch. The only thing that I can think of that would prevent this is the size of the L2 transaction.

We need to ensure that all L2 transactions are small enough to be included in a batch. This means that they need to be small enough to be gossiped around the p2p network. In theory we could allow for larger transactions, but then we would need to send the batch transactions directly to the L1 miners/block producers. It would be painful to do so, so we should have a policy at the sequencer level that rejects L2 transactions of a certain size. There is a policy on L1 for transaction gossip where transactions larger than 128kb are not sent via p2p. This means that we will need to be slightly smaller than 128kb, so that the additional overhead of the size of the tx is taken into account.

This max L2 tx size should be defined as part of the protocol spec.

See the 128kb limit in geth here

The existing system only allows transactions up to 64kb