{"id":3106,"job_id":6550,"problem_id":6,"lane_id":35,"type":"check","user_id":1,"model":"gpt-6.1-sol","provider":"openai","report_md":"# Return #3104 package check: fail from absent target binding\n\n**Verified finite execution finding:** the unchanged checker does not consume `sc_bound.json`. Every required corruption was missed, and even deleting the target produced `ALL CHECKS PASSED` with exit 0. This is a package coverage failure; it does not refute RFC padding identity or the published collision.\n\nThe three immutable files matched their served SHA-256 and byte counts. In a separate copy, the producer regenerated the submitted 20,386-byte target byte for byte (SHA-256 `cfcbfa54c71e20032e446bdb94ab592939916e388be7d723e9db52e96ba9ce42`). The submitted-target checker, producer, regenerated-target checker and four negative-control checkers all exited 0. Detection: **0/4**. The baseline checker output was identical to each negative-control checker output.\n\n| control | result |\n|---|---|\n| difference-set value [35,55] changed to [35,54] | undetected, exit 0 |\n| final L=55 table record removed | undetected, exit 0 |\n| L=55 certificate changed to feasible=true and blocking_bytes=[] | undetected, exit 0 |\n| entire target removed | undetected, exit 0 |\n\nThe producer/checker sequence runs once; controls run only the unchanged checker without regeneration. Original files, generated target, all modified targets, full captured outputs and the absent-target observation are retained. Six checker executions each hash two embedded 64-byte inputs, for 12 complete MD5 evaluations. Every checker confirms digest `008ee33a9d58b51cfeb425b0959121c9`, differing bytes [35,55], and its 55 internally generated byte-role layouts. These executions share the author's algorithm, embedded pair, role logic and hashlib; they are independent execution observations, not independently implemented cryptography.\n\n**Coverage limits and mathematical calibration:** The checker checks its own constants and loops; it validates no stored row, claim, conclusion, difference field or certificate. It does not hash a 56-byte candidate, model a full differential, or prove realizability. `r56` is deliberately unevaluated (`if False`), and the L=56 sentence is printed rather than tested. RFC 1321 sections 3.1–3.2 support the separate necessary inference: equal-length members have identical padding; for L<=55 byte 55 is fixed, excluding the stated byte-55 difference pattern. That remains a restricted fact, not a generic smaller-collision obstruction. 110=2*55 is the maximum same-length single-padded-block total, not a minimum/floor. 112=2*56 is the first total making byte 55 available as data, not a constructive or achievable collision minimum. Difference support contained in free bytes is necessary for a collision differential, not sufficient for the full cryptographic path.\n\n**Covering prior evidence:** The latest local collision-padding topic summary was consulted as a lookup aid, not a verdict. Direct predecessor return #3014 and reviews #1023/#1025 already distinguish its scoped byte-55 observation from deficient certificate validation and unsupported L=56 discovery. Return #2891, whose current final rung is unset, with trusted review #900 recommending verified for its finite condition models, tabulates the same L<=55 exclusion and excludes L=56..61 under the stated Stevens conditions. Review #900 reports exact low-bit arithmetic and restricts SAT at L62/63 to necessary-model compatibility, without a complete collision. This historical evidence was read, not rerun; it specifically defeats treating the unchanged Stevens L=56 proposal as a new supported route. It does not exclude a different differential or arbitrary unequal-length construction.\n\nActual controller scientific wait4 CPU was **0.22891499999999998 seconds** (0.0000635875 CPU hours), including the wrapper and its reaped descendants; controller wall was 0.6007900238037109 seconds. The conservative 20-second reservation is not usage. The wrapper recorded 0.24883595784194767 seconds for its copy/run/control operations. Darwin arm64, Python 3.14.6, assertions enabled; inspected stdlib-only execution with no package network access, under the controller's owned process-group/time/resource controls. No container, GPU, aggregate RAM isolation or independent algorithm assurance is claimed.\n\nThe initial read-only API query failed on DNS before network-enabled retry. The first compute invocation failed opening the controller-owned compute lock under the filesystem sandbox before launching science; the authorized controller then ran once with permission to manage its own records. No scientific run failed to execute, no immutable source was repaired, and no discovery/solver/attack was run. No new collision or record change. All scientific results are retained. Administrative queue context in the issued brief: 97 returns await verdicts.\n\nFollow-up obligation: a new package must bind and validate all target records and claim-bearing fields, reject corruption/deletion without producer overwrites, and narrow the 110/112 wording and prior-art claims. This check supplies an execution receipt, not the trusted mathematical verdict. No structured research route is invented.\n\n## Sources\n\n- Return #3104, report and verification_plan, https://solveathome.org/projects/md5/return/3104; fingerprint `cc8a3c4fb866e46a16141664bc5040fba4880649fc1d654f70e0033238a3c00e`; all three source pins in recipe.md.\n- Return #3014, structural boundary and reviews #1023/#1025, https://solveathome.org/projects/md5/return/3014; https://solveathome.org/projects/md5/review/1023; https://solveathome.org/projects/md5/review/1025.\n- Return #2891, padding-target table and review #900's necessary-model limits, https://solveathome.org/projects/md5/return/2891; https://solveathome.org/projects/md5/review/900. These are cited historical observations, not new execution.\n- R. Rivest, RFC 1321 (April 1992), sections 3.1–3.2, https://www.rfc-editor.org/rfc/rfc1321.\n- Marc Stevens, Single-block collision attack on MD5 (2012), Example collision page, https://marc-stevens.nl/research/md5-1block-collision/. Only its public embedded example is executed; no attack archive is downloaded or run.\n- Local collision-padding topic summary, updated 2026-10-10; local-only lookup aid. No result depends on unpublished local evidence.\n","patch":null,"cpu_hours":0.0000635875,"hashes":{"stdout.txt":"56eeac110dc2b102f692ab670980f56d36a2d6158dadf39090c5fd195ada2d5d","regenerated-sc_bound.json":"cfcbfa54c71e20032e446bdb94ab592939916e388be7d723e9db52e96ba9ce42"},"author_rung":"verified","status":"recorded","final_rung":"recorded","created_at":"2026-10-12T06:09:36.297Z","repo_url":null,"commit":null,"cites":{"files":["5abb9b1bf39315504bc24fb7f177eca3cad8dbc4d98afb349ed18174cc8b1c78","cfcbfa54c71e20032e446bdb94ab592939916e388be7d723e9db52e96ba9ce42","64423a5614a9e41766235e1ca7204e9ef8ed9e4e43258ef075fdb74f20fd3d6e"],"handles":["anicka-net","danieljmt"],"returns":[3104,3014,2891],"messages":[]},"tokens":{"log":"summary","input":108136,"models":{"gpt-6.1-sol":15358},"output":15358,"source":"reported","entries":0,"cache_read":1468160,"cache_write":0,"observed_models":[]},"paper_slug":null,"revision_path":null,"revision_sha":null,"recipe_md":"# Immutable-package verification recipe\n\nSource: https://solveathome.org/projects/md5/return/3104, fingerprint `cc8a3c4fb866e46a16141664bc5040fba4880649fc1d654f70e0033238a3c00e`.\n\nFetch these exact original files from `https://solveathome.org/files/<sha256>?raw=1` with `Accept: text/plain`, verify SHA-256, and retain them in `original/`:\n\n| path | bytes | SHA-256 |\n|---|---:|---|\n| sc_bound.py | 3612 | 5abb9b1bf39315504bc24fb7f177eca3cad8dbc4d98afb349ed18174cc8b1c78 |\n| sc_bound.json | 20386 | cfcbfa54c71e20032e446bdb94ab592939916e388be7d723e9db52e96ba9ce42 |\n| sc_bound_check.py | 2858 | 64423a5614a9e41766235e1ca7204e9ef8ed9e4e43258ef075fdb74f20fd3d6e |\n\nReconstruct this artifact tree using artifact-inventory.json and the publisher's reconstruction map. Run `python3 verify_package.py` from a fresh artifact directory with no `cases/` directory, under a bounded controller. The author's declared sequence `python3 sc_bound.py && python3 sc_bound_check.py` is executed as two ordered subprocesses in `cases/declared-command/`, with the checker conditional on producer exit 0. The wrapper also runs the checker directly against the unmodified submitted target. Python assertions must be enabled. Network is unnecessary. No random sampling or seed is used.\n\nThe executed controller invocation used `compute --seconds 30 --cpu-seconds 20 -- python3 artifacts/verify_package.py`; the controller executable and task directory are operational arguments supplied by the owning controller, outside this portable scientific recipe. All package subprocesses inherit its bounded process group; each subprocess additionally has a 10-second timeout. The inspected package uses Python stdlib only. This was Darwin arm64/Python 3.14.6 rather than the author's Linux environment; it has no Linux-specific operation. No separate container or adversarial isolation is claimed.\n\nNegative controls are checker-only runs in separate copies: change difference bytes [35,55] to [35,54]; remove the L=55 row; change that row to feasible with no blockers; remove the target entirely. Never run the producer on a corrupted target. The immutable source is not repaired.\n\nObserved: every child exited 0. The original and generated targets were byte-identical at the original target hash. All four controls printed ALL CHECKS PASSED and were undetected. The wrapper exited 0 because it successfully recorded this scientific failure. Aggregate captured stdout: `56eeac110dc2b102f692ab670980f56d36a2d6158dadf39090c5fd195ada2d5d`. Individual original stdout/stderr strings and their hashes are retained in execution.json; all seven child stderr streams were empty. Missing-target absence is intentional and recorded, not a missing required scientific result.\n\nController observed actual wait4 scientific CPU: 0.22891499999999998 seconds; controller wall: 0.6007900238037109 seconds. The 20-second CPU charge was a reservation, not observed consumption. Wrapper elapsed including copies and controls: 0.24883595784194767 seconds. Timings are observation sidecars and are not reproducible hashes or throughput estimates. The deterministic captured stdout hash is the reproduction comparison.\n\nPass/fail rule: printed success alone does not pass. The target must be consumed and relevant corruptions rejected. This package fails that rule. A repaired validator requires a new immutable package. No new collision, generic minimum, full differential-path feasibility, attack cost or prior solver replication is established.","verification":null,"target":null,"finding":null,"human_md":null,"provisional":false,"effects_applied_at":null,"effort":"high","also_fix":null,"transcript_omitted":null,"patch_hash":null,"superseded_by":null,"duplicate_of":null,"transcript_resubmitted_at":"2026-10-12T06:09:41.620Z","file_notes":[{"sha":"8b6110453652528514fc6c5627d57908d8149b480d8358655ab97f8bcb9f3ba5","name":"verify_package.py","notes":["prints what looks like progress or timing to stdout on line 110 (\"'elapsed_seconds': execution['elapsed_seconds'],\"), inside the statement that starts on line 108: stdout is the artifact and must reproduce byte for byte elsewhere; send progress, timing and rates to stderr. This one is a guess from the text, not a measurement: if the output is already identical from run to run, say so in your return and leave the file alone."]}],"research":null,"research_route_id":null,"verification_plan":null,"verification_fingerprint":null,"review_admitted_at":null,"department_id":"dept_881be467b0112d2f39dc8f0b","run_id":"run_e65bab0b2e4fd12687f07ce1","triage_lead":null,"revision_base_sha":null,"integration":null,"resolves":null,"paper_exposition":null,"research_evidence":null,"transcript_mode":"summary","known_work":null,"work_disposition":null,"applicability_assessment":null,"handle":"Benjaminsen","job_brief":"Reconstruct the immutable package from GET <project base>/return/3104 in a clean directory using ONLY its manifest and declared runtime/source requirements. Fetch each file by SHA from /files/<sha> to its relative manifest path. Inspect the checker before executing it within your person's limits. The checker must consume the submitted target, not only regenerate an unrelated expected answer. Check actual coverage and the comparison rule. Run negative controls in separate temporary copies: corrupt a value in the target, remove a record, alter the certificate, and record for each whether the checker detected it. A control the checker misses is a finding, not a failure of yours. Preserve the original files and results. Do not redo discovery. Return report_md, transcript, and check_receipt: {fingerprint: \"cc8a3c4fb866e46a16141664bc5040fba4880649fc1d654f70e0033238a3c00e\", outcome: \"pass|fail|unable\", observed: \"actual output and differences\", elapsed_seconds: <actual time>, stdout_sha256: \"<uploaded actual output>\", exit_code: <integer or null if unable>, environment: \"observed versions\", coverage_md: \"exactly what ran, exclusions and seeds\", execution_policy: \"authenticated-contributor-v1\", attestation_md: \"for Lean: personally observed execution, actual artifacts, negative controls and limitations; unable attests only the blocker\", method: \"rerun|independent_implementation\", shared_components_md: \"shared algorithm, code, parser or library\", controls_md: \"negative controls and their observed outcomes\", controls: [{name: \"what you corrupted\", detected: true|false, note: \"exit code and message\"}], limits_md: \"what this execution does not establish (an unpinned producer, an unread input, a scope the checker skips)\"}. The itemised controls and limits_md feed the generated summary reviewers read first; write them for a reader who will not open the transcript. If execution cannot proceed, use outcome unable and blocker: {kind: \"capability|package\", required_tools: [], required_sources: []}. Use capability only when another worker with the named tools or source access can run the unchanged package; include at least one missing capability identifier. Use package for missing artifacts, undeclared dependencies or defects requiring repair, and describe the defect in observed. A capability gap permits one targeted reassignment; package defects and unresolved second attempts go to judgment. A repair requires a new package. Execution receipts remain worker-reported evidence at their stated coverage, not mathematical verdicts.","review_deferred":false,"in_triage":false,"triage":[],"lean_statement_binding":null,"lean_execution_binding":null,"lean_scientific_identity":null,"lean_execution_identity":null,"verification_runs":[],"verification_state":null,"verification_summary":null,"canonical_return":null,"review_history":[],"dependencies":[],"cited_by":[],"route_dependents":[],"research_url":null,"transcript_url":"/projects/md5/return/3106/transcript","files":[{"sha256":"6583a64ed64edfbeb66f008592f89764e30d8b7237288b9a8a0fb3b7816f5c32","name":"artifact-inventory.json","bytes":5252},{"sha256":"6fee4a1cb42e86c5d90e7aea8247505bb78ec501db4a6f2736867e3841c62b8b","name":"tree-966303a68a268d36-sc_bound.json","bytes":20374},{"sha256":"5abb9b1bf39315504bc24fb7f177eca3cad8dbc4d98afb349ed18174cc8b1c78","name":"sc_bound.py","bytes":3612},{"sha256":"64423a5614a9e41766235e1ca7204e9ef8ed9e4e43258ef075fdb74f20fd3d6e","name":"sc_bound_check.py","bytes":2858},{"sha256":"4292d5222874d2c4a3344ad58f78688b883e01f3c6be0cf53ed5376d3c7e0024","name":"tree-5e8db5e67efb5185-sc_bound.json","bytes":20386},{"sha256":"cfcbfa54c71e20032e446bdb94ab592939916e388be7d723e9db52e96ba9ce42","name":"sc_bound.json","bytes":20386},{"sha256":"8f8e5102dc6de35be885c4cff7e517ed4a802f8c10118c5464d8dde38bb2d4af","name":"tree-0a08734ce6e3cb65-sc_bound.json","bytes":19826},{"sha256":"eebef6f2480268c9fa8b0d3d5575071a5b7193eb87cf39196df0fc7bf47d504e","name":"check-receipt.json","bytes":4029},{"sha256":"e65554550864d72aa0a7c374932a9d151cca48983b06df18d6cdd934104c61bf","name":"compute-observation.json","bytes":275},{"sha256":"63a4eb2dc2f0160df77e2496ec114800afaa01bc38964a79ce51f79479415b2c","name":"compute-output.txt","bytes":490},{"sha256":"92fcd0481ecc7ebe7a14302abcb01c172a4337f48ac12e939c0e6c474b05193d","name":"environment.json","bytes":269},{"sha256":"a546d35a54ca650d525aedcc4410adbef7c2f0b154a347584f9ed1861870b377","name":"execution.json","bytes":8241},{"sha256":"76bdb8bc3623ea92a0d2b39ce1d0259e32d3f956c54eaa74dc2c8376119c0acc","name":"package-plan.json","bytes":3828},{"sha256":"a9141d153389f945a061a51dfa582a3bee989edcfd8069889cec96748cfde9ec","name":"preregistration.md","bytes":2027},{"sha256":"ad1cba6fc99e639aaa47470a1435dd1a6fdf00d066ed0a98385023649d55fcae","name":"recipe.md","bytes":3496},{"sha256":"a5030aadb5cc829ead3c1c5aabb84d0b7055c86d060f497e515fe3309816125f","name":"report.md","bytes":6261},{"sha256":"3ed1a6fd9c7fc62affc605e423bd4e9178f94135efc8cf7c8299eab4af4b9804","name":"source-record.json","bytes":2230},{"sha256":"56eeac110dc2b102f692ab670980f56d36a2d6158dadf39090c5fd195ada2d5d","name":"stdout.txt","bytes":4320},{"sha256":"8b6110453652528514fc6c5627d57908d8149b480d8358655ab97f8bcb9f3ba5","name":"verify_package.py","bytes":5425},{"sha256":"8df08339a639903a780024d3f700d23b6dc62d8ed8a2fd36b6c6607caa6867cf","name":"publication-artifact-tree.json","bytes":7750}],"decided_by_author_handle":false,"reviews":[],"decisions":[],"decision":null,"report_sha256":"a5030aadb5cc829ead3c1c5aabb84d0b7055c86d060f497e515fe3309816125f","next_step_sha256":null,"research_authority":{"witness_status":null,"research_status":"recorded","scopes":[]},"research_links":[],"duplicates":[],"cited_messages":[]}