Why Batch Transactions Expose the Flaws in EOA Sessions

EOA session keys fail at scale. They grant temporary, broad permissions to a third party, creating a security model that is either too permissive for complex actions or requires constant, costly re-authorization for each step.

Batch execution exposes this brittleness. A single transaction bundle for a DeFi strategy on Uniswap or Aave requires pre-approving every asset and contract, a UX nightmare that intent-based architectures like UniswapX and CoW Swap solve by design.

The evidence is in the gas. Users pay for each approval and execution step. Protocols like Safe{Wallet} and ERC-4337 smart accounts demonstrate that native batching and sponsored transactions are the required infrastructure shift.

EOA sessions are stateful. They lock a user's account to a single dApp's logic, creating a fragile, sequential workflow that breaks atomic composability. This prevents a wallet from executing a cross-DEX arbitrage or a UniswapX-style fill across multiple chains in a single, guaranteed operation.

Batch transactions are stateless workarounds. Protocols like Safe{Wallet} and Rabby Wallet simulate atomicity by bundling calls, but this is a client-side illusion. The underlying EOA still signs a linear list, exposing users to sandwich attacks and failed state transitions if any single call reverts.

The market demands intent abstraction. Users express desired outcomes (e.g., 'buy this NFT with the best price'), not manual transaction sequences. The rise of UniswapX, CowSwap, and Across proves the demand for declarative, risk-minimized execution that the EOA session model structurally cannot provide.

Evidence: Over 60% of Ethereum's top 100 contracts by gas usage are now proxy or modular accounts (ERC-4337, Safe). The infrastructure is already migrating away from the native EOA, rendering its session management obsolete for advanced use cases.

EOA sessions centralize risk. A user grants a dApp a session key to sign a batch of future transactions, trading granular control for convenience. This recreates the custodial risk of a centralized exchange, where a single compromised key exposes all approved actions.

The approval is the vulnerability. Unlike a smart contract wallet with social recovery, a leaked EOA session key grants irrevocable access. Projects like dYdX and gaming platforms popularized this model, prioritizing fluid UX over the self-custody principle.

Batch transactions reveal the flaw. A session enabling a swap on Uniswap and a bridge via LayerZero in one click is the goal. The security failure is bundling unlimited, future permissions into one all-or-nothing signature, a clear regression from per-transaction signing.

Evidence: The ERC-4337 Intent. The rise of ERC-4337 account abstraction and intent-based systems like UniswapX and CowSwap is a direct market response. These systems execute complex user intents without handing over private keys, proving the session key model is a dead-end.

EOAs are atomic by design. Every EOA transaction is a single, indivisible operation signed by a private key. This atomicity prevents bundling multiple actions, forcing protocols like Uniswap and Aave to require separate approvals and executions.

Session keys create a false equivalence. EOA 'sessions' via tools like Particle Network or ERC-4337 wallets simulate batching by pre-signing future actions. This is delegation, not true atomic batching, and introduces persistent security trade-offs.

The cost is quantifiable inefficiency. Users pay gas for each atomic step. A simple swap on a DEX aggregator like 1inch often requires two transactions, doubling base network fees compared to a single batched operation.

Smart contract wallets solve this. Accounts like Safe{Wallet} or ERC-4337 smart accounts are contracts, enabling true atomic multi-call bundles. This architectural shift is why intent-based systems (UniswapX, CowSwap) rely on solver contracts, not EOAs.

EOA sessions fail at composability. They are single-chain, single-contract constructs. A gaming session key cannot sign a cross-chain swap on Across or a multi-step DeFi operation without a new approval.

Batch execution is impossible. An EOA session signs one action. Complex intents requiring multiple steps—like a Uniswap swap followed by a deposit into Aave—require separate, sequential signatures.

Security is a binary trap. The session is either fully trusted or useless. There is no granularity for partial permissions, like allowing swaps but not transfers, which ERC-4337 account abstraction enables.

Evidence: The rise of intent-based architectures like UniswapX and CowSwap proves the market demands abstracted, batched execution that EOAs cannot provide.