Layer 1 is the base blockchain. It provides security, consensus, and settlement finality. Bitcoin and Ethereum are Layer 1 networks. Transactions finally settle there. That chain is the source of truth. Security comes from the consensus rules and the economic value backing them. Ethereum Layer 1 is secured by hundreds of billions of dollars in staked ETH.
Attacking it would mean acquiring a majority of that stake, which is economically impractical.
The tradeoff is throughput. Ethereum Layer 1 processes roughly 15 transactions per second. Bitcoin handles about 7. Every validator must process every transaction if the network stays decentralized. Raising L1 throughput means larger blocks that fewer nodes can handle, or faster consensus that concentrates operators. That trilemma, security, decentralization, scalability, is why Layer 2 exists.
Rather than weaken Layer 1, faster layers settle back to it. The trade-off is scalability. These constraints exist because every validator must process every transaction to maintain decentralization. Rather than changing Layer 1 properties and compromising its security, faster layers are built on top that inherit Layer 1 security for final settlement.
A Layer 1 is the base chain that settles itself: Bitcoin, Ethereum, Solana. Layer 2s post back to a Layer 1.
Layer 1 Blockchain Security
Explore how base blockchain protocols maintain security through consensus mechanisms
Ethereum Layer 1
Network Security
Network is secure. Attack would require massive resources.
Consensus Mechanism
Key Insight: Layer 1 networks are the foundational source of truth. Their security comes from the economic cost of attacking them - requiring control of majority stake or mining power worth billions of dollars.