Unconstrained Data

Unconstrained data is used for large blobs (like EVM bytecode) that are too expensive to verify inline. Instead, HDP verifies a hash and then returns the raw data.

Use case: EVM bytecode

The unconstrained memorizer returns bytecode and verifies it against the account code hash:

• Fetch bytecode during dry run and record a key
• During sound run, load the bytecode from memorizer
• Compute keccak(bytecode) and compare to account_get_code_hash

Dry-run behavior

The dry-run handler fetches bytecode via RPC (eth_getCode) and stores it as BytecodeLeWords in the unconstrained key set.

BytecodeLeWords stores the bytecode as little-endian 64-bit words plus a final partial word.

Cairo API

hdp_cairo/src/unconstrained/state.cairo exposes:

• evm_account_get_bytecode(hdp, key) -> ByteCode

If the hash check fails, execution halts with Account: code hash mismatch.