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HDP uses specialized state paths so sound execution is offline, deterministic, and fast.

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Memorizers

Memorizers are Cairo0 dictionaries populated during verification, then read during module execution. Core memorizer domains:
  • EVM: headers, accounts, storage, txs, receipts, logs
  • Starknet: headers, storage
  • Injected state: custom trie-backed state
  • Unconstrained: large blobs validated by hash

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Injected state

Injected state is a custom persistent state model backed by a Patricia trie and served by state_server. Typical use:
  1. Start State Server
  2. Provide --injected_state <json> in dry run and sound run
  3. Fetch state proofs during stage 2
  4. Read/write with hdp.injected_state APIs in your module
State server base URL:
  • INJECTED_STATE_BASE_URL
For full setup, endpoints, and examples, see State Server.

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Unconstrained data

Unconstrained mode is used for large payloads like EVM bytecode. Flow:
  • Dry run collects the key and payload source
  • Sound run loads payload from memorizer
  • HDP validates payload hash (for bytecode, against account code hash)
Cairo helper:
  • evm_account_get_bytecode(key) -> ByteCode
This gives efficient access to large data while preserving integrity guarantees. For troubleshooting injected state flows, see Debugging.