Security and data availability

Elysium is an optimistic rollup that settles to HyperEVM. It launches with the standard posture for Nitro chains and a staged path to permissionless fraud proofs.

Launch posture

• Single sequencer with neutral priority-fee ordering.
• Permissioned validation at launch, moving to permissionless fraud proofs (Arbitrum BoLD) as the chain matures.
• Optimistic withdrawals that finalize after a challenge period.

Data availability

Elysium uses AnyTrust data availability. A k-of-n committee stores the full transaction data and attests to it with a compact certificate posted to HyperEVM. A single honest committee member is enough to keep the data available.

If the committee is ever unavailable, the chain automatically posts full data to HyperEVM instead. That raises costs but never halts the chain.

What users keep unconditionally

• Forced inclusion. Transactions can be forced through the delayed inbox on HyperEVM even if the sequencer censors them.
• Withdrawal safety. Withdrawals are protected by the challenge period.
• HyperCore custody. Assets on HyperCore sit in users' own HyperCore accounts. Revoking a trading agent or acting with the master key never involves Elysium.

HyperCore integrations

• The keeper adds no custodial trust. Agents are trade-only by HyperCore's own enforcement, and the signing service is substitutable. See Trading on HyperCore from Elysium.
• Market data is auditable. Every precompile response carries the HyperCore block it was derived from and commits to the bytes it serves, so it can be checked against archived HyperCore data. The data path fails visibly stale rather than silently wrong. See HyperCore market data.

Token bridges

Each bridge leg has its own invariant and trust notes, covered in Token bridging architecture.