Why AA Will Force a Reckoning for Modular Security Models

Paymasters pay gas fees on behalf of users, creating a new MEV vector. Attackers can front-run subsidized transactions or extract value from paymaster logic, turning a user convenience into a systemic risk.

• New MEV Surface: Bots can exploit subsidy conditions and fee refunds.
• Trust Assumption: Users must trust paymaster's solvency and non-censorship.
• Protocol Bloat: Security now depends on off-chain paymaster infra (e.g., Stackup, Biconomy).

Session keys enable gasless transactions for a set period, but a compromised key grants an attacker a free, unlimited operation window. Modular chains with slow fraud proofs are especially vulnerable.

• Extended Attack Window: A stolen key is valid for hours/days, not per-transaction.
• Cross-Rollup Threat: A session key on a zkSync or Starknet AA wallet can be abused across any dApp it's authorized for.
• Delayed Finality: Optimistic rollups with 7-day challenge periods cannot react in time.

Bundlers are the privileged nodes that package UserOperations. Their centralization creates a single point of failure for transaction inclusion, directly contradicting modular decentralization goals.

• Replica Risk: The Flashbots/block builder centralization problem repeats at the bundler layer.
• Censorship Vector: A dominant bundler (e.g., Alchemy, Blocknative) can blacklist addresses or dApps.
• Fee Market Distortion: Bundlers can extract maximum value before passing transactions to the base layer.

Projects like Espresso and Astria offer cross-rollup sequencing to unify liquidity and ordering, but they create a new, centralized trust layer. The security of a user's cross-chain AA session depends on a single sequencer set.

• Creates a new super-node: A failure or censorship attack here breaks the entire cross-chain UX.
• Weakens economic security: Decouples execution from the underlying L1's consensus, reducing slashing guarantees.
• Vendor lock-in risk: Rollups become dependent on a specific sequencer network's liveness.

Architectures like UniswapX, CowSwap, and Across use solvers to fulfill user intents across chains, abstracting complexity. However, they offload security to an off-chain auction mechanism.

• Solver cartel risk: Economic incentives can lead to solver centralization, reducing competition and fairness.
• No settlement guarantees: Users get atomicity for a successful fill, but lack cryptographic proof of failure, relying on reputation.
• MEV leakage: The competitive solver model inherently captures and redistributes user surplus value.

LayerZero and CCIP sell themselves as universal messaging layers for AA wallets. Their security models, however, rely on external oracle/relayer sets or off-chain committees that become single points of failure.

• Security is not additive: A hub's security is only as strong as its weakest approved oracle/relayer.
• Governance capture: The entity controlling the whitelist becomes a powerful censor.
• Costly verification: Light clients for every connected chain are impractical, forcing trust in attested state.

EigenLayer allows ETH stakers to re-stake their capital to secure new systems (AVSs), like cross-chain bridges or shared sequencers. This bootstraps security but creates systemic risk.

• Correlated slashing: A failure in one AVS (e.g., a bridge hack) can slash stake backing unrelated services.
• Yield-driven centralization: Operators will flock to the highest-yield AVSs, creating security monocultures.
• Liquidity fragmentation: Ties up massive ETH liquidity that could be used for L1 consensus or DeFi.

AA's intent-based architecture decouples transaction signing from execution. This breaks the atomic security guarantee of a single sequencer. A user's multi-step operation can now span multiple rollups and chains, creating a coordination attack surface.

• Key Risk: Cross-domain MEV and liveness attacks between execution layers.
• Key Impact: Security models like shared sequencers (e.g., Espresso, Astria) must now guarantee cross-rollup atomicity, not just single-chain.

Security must shift from protecting a state transition to verifying the fulfillment of a user's declared intent. This requires new verification layers that sit above execution environments.

• Key Primitive: Succinct Proofs (e.g., from RISC Zero, SP1) to verify cross-domain intent fulfillment.
• Key Primitive: Intent Solver Reputation Systems to penalize malicious solvers (like in UniswapX or CowSwap).

AA introduces sponsored transactions via paymasters. This creates a new, highly centralized fee market oracle and censorship point. A dominant paymaster (e.g., a large wallet provider) becomes a single point of failure for network access.

• Key Risk: ~$1B+ in staked assets could be required to decentralize paymaster stakes effectively.
• Key Impact: Modular security must now account for social consensus and liveness of fee abstraction.

Decentralize the paymaster function by treating it as a separate modular service with its own staking, slashing, and attestation layer. Think EigenLayer for gas sponsorship.

• Key Design: Bonded Paymaster Pools where operators stake to sponsor specific transaction policies.
• Key Design: Fallback Mechanisms using canonical gas tokens if the paymaster network fails, ensuring liveness.

AA enables session keys for seamless app interaction, but these delegated signing keys create massive, persistent attack surfaces. A compromised session key can drain assets across multiple dApps and chains in ~seconds.

• Key Risk: Security is now defined by the weakest dApp's key management, not the underlying L1/L2.
• Key Impact: Modular chains inherit the risk profile of every AA wallet and dApp built on them.

Move key management and policy enforcement into a dedicated, upgradable security module within the AA wallet. This PSM becomes a user's personal security layer, interoperable across any chain.

• Key Feature: Chain-Agnostic Policies (e.g., spend limits, circuit breakers) enforced at the PSM level.
• Key Feature: ZK-Proofs of Policy Compliance submitted with transactions, reducing on-chain verification load.