apollo_starknet_os_program: restore keccak syscall in virtual OS

[Yoni-Starkware]

Stack:

• starknet_os_flow_tests: add multicall prove test; drop balance_of test #14082
• workspace,starknet_proof_verifier: bump privacy-{prove,circuit-verify} to 039e52c, add v0/v1 aliases #14017
• ▶ apollo_starknet_os_program: restore keccak syscall in virtual OS #14071 (this PR)

Summary

• Re-adds the keccak syscall to the virtual OS — reverts the removal from apollo_starknet_os_program: remove keccak syscall from virtual OS #12355. The KECCAK_SELECTOR arm is restored in execute_syscalls__virtual.cairo so virtual-OS proofs can again contain transactions that call the keccak syscall.
• Bumps the latest allowed_virtual_os_program_hashes entry (in blockifier_versioned_constants_0_14_3.json and constants.cairo) to the new virtual OS program hash, replacing the previous keccak-disabled hash.
• Drops the now-redundant Keccak arm in test_contract::test_forbidden_syscall_in_virtual_mode and the corresponding rstest case in virtual_os_test::test_forbidden_syscall.
• Uncomments the serialize_call("test_keccak", &[]) line in prove_and_verify_multicall_tx (added by stacked PR starknet_os_flow_tests: add multicall prove test; drop balance_of test #14082) so the multicall test now exercises the keccak syscall path via the virtual OS.

Auto-regenerated fixtures:

• program_hash.json virtual_os hash
• versioned_constants_diff_regression/0.14.2_0.14.3.txt
• bouncer_test::class_hash_migration_data_from_state expected sierra/proving gas
• stack_trace_regression/test_contract_ctor_frame_stack_trace_cairo1_casm.txt

Test plan

• cargo test -p apollo_starknet_os_program test_program_hashes (with UPDATE_EXPECT=1)
• cargo test -p apollo_starknet_os_program test_os_constants (with UPDATE_EXPECT=1)
• cargo test -p starknet_os test_virtual_os_program_hash_is_allowed
• cargo test -p blockifier test_vc_diffs_regression (with UPDATE_EXPECT=1)
• cargo test -p blockifier --lib bouncer:: (regen'd snapshots)
• cargo test -p starknet_os_flow_tests virtual_os_test::test_basic_happy_flow
• cargo test -p starknet_os_flow_tests virtual_os_test::test_forbidden_syscall (remaining cases pass)
• Local prove+verify via prove_and_verify_multicall_tx -- --ignored (requires --features starknet_transaction_prover/stwo_proving --release + nightly)

[cursor]

PR Summary

Medium Risk
Re-enables a previously disabled syscall in virtual OS mode and bumps the allowed virtual OS program hash, which can affect proof compatibility and any clients pinned to prior hashes. Risk is mostly around consensus/verification mismatch if any component still expects the old virtual OS hash or syscall set.

Overview
Restores support for the keccak syscall in virtual OS execution by wiring KECCAK_SELECTOR back into execute_syscalls__virtual.cairo and calling execute_keccak.

Bumps the virtual OS program hash everywhere it’s pinned/validated (constants.cairo, program_hash.json, Blockifier versioned constants + diff regression) and updates snapshots/fixtures (virtual OS bytecode length, bouncer gas expectations, and systest preconfirmed block blob fixtures).

Adjusts virtual-OS security tests to reflect that keccak is now allowed (removes it from the forbidden-syscall cases) and updates the ignored multicall prove+verify test to exercise test_keccak again.

^{Reviewed by Cursor Bugbot for commit cec96b1. Bugbot is set up for automated code reviews on this repo. Configure here.}

[reviewable-StarkWare]

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[AvivYossef-starkware]

@AvivYossef-starkware reviewed 6 files and all commit messages, and made 1 comment.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on Yoni-Starkware).

---

Cargo.toml line 337 at r1 (raw file):

pretty_assertions = "1.4.0"
primitive-types = "0.12.1"
privacy-circuit-verify = { git = "https://github.com/Yoni-Starkware/proving-utils", rev = "95bc227" }

consider adding v1 to be consistent with ProofVersion enum

Code quote:

privacy-circuit-verify

[AvivYossef-starkware]

Where does it "Re-adds the keccak syscall to the virtual OS"? The PR description/name is misleading

@AvivYossef-starkware made 1 comment.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on Yoni-Starkware).

[Yoni-Starkware]

In the beginning, the virtual OS contained keccak

@Yoni-Starkware made 1 comment.
Reviewable status: 0 of 15 files reviewed, all discussions resolved (waiting on AvivYossef-starkware).

[Yoni-Starkware]

@Yoni-Starkware made 1 comment.
Reviewable status: 0 of 15 files reviewed, all discussions resolved (waiting on AvivYossef-starkware).

---

Cargo.toml line 337 at r1 (raw file):

Previously, AvivYossef-starkware wrote…

consider adding v1 to be consistent with ProofVersion enum

Done in prev PR

[Yoni-Starkware]

@Yoni-Starkware reviewed 17 files and all commit messages.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on Yoni-Starkware).