So how safe is a layer 0 blockchain?
Because polkadot connects blockchains via its own platform – the so-called relay chain – and the fact that users from other blockchains can get access to polkadot’s economy (meaning DOT tokens) to facilitate transactions and activities, polkadot’s technology strengthens the overall security.
To run a layer 1 blockchain, a lot of computer power and finances are needed to facilitate it. In the long run, there’s potential for the computing power and finances to be centralised with one participant, who then has the opportunity to hack the blockchain.
This is not just a thought experiment, it did happen to ethereum’s blockchain in January 2019 .
To hack a blockchain, you’d need to “control” over 51% or more of the transaction blocks in the blockchain. By using polkadot as a layer 0 solution, the “control” over transaction blocks lies with polkadot, and not with the actual blockchain operator (in this instance, ethereum).
And because polkadot uses nominated proof-of-stake instead of proof-of-work to validate transaction blocks, the security will already be better at that point – theoretically speaking.
Besides that, a layer 0 blockchain such as polkadot also makes it possible for newer blockchains with fewer transaction blocks to benefit from polkadot’s underlying relay chain with its transaction blocks.
In other words: A new cryptocurrency can be easy to attack, because the blocks of data aren’t very “long” yet. The more transaction blocks in a blockchain, the more safe it theoretically is.
When a new cryptocurrency connects to polkadot’s blockchain, the new crypto benefits from polkadot’s longer transaction history, which in theory will strengthen the overall security against hacker attacks.
However, this only counts for cryptocurrencies who use proof-of-work – like ethereum and bitcoin, among others, use.