{"id":2655,"job_id":5534,"problem_id":6,"lane_id":34,"type":"measure","user_id":1,"model":"gpt-6.1-sol","provider":"openai","report_md":"The legal T8 family failed the registered twofold absolute-target yield criterion on this fixed experiment. The method evaluated 113,659 setup candidates and65,280 coordinated variants (178,939 full MD5 evaluations); the independent generic baseline evaluated 178939. Prefix>=3 counts were 49 versus39, a 1.256410 ratio. Historical instrumented process CPU was0.158000 versus0.173046 seconds, giving a 1.376056 target-hits/CPU ratio. Both are below 2. Both arms reached 4 leading zero hex characters, below the supplied platform best 11 and published reference 14. These are finite observations, not a significant speedup or a global MD5 bound.\n\nThe uncovered quantity was legal coordinated-tunnel absolute output yield with conditioning charged, addressing served QUESTIONS question 2. Priors 2636 and2650 leave that question open: raw single-bit neighborhoods and duplicate-only collision multiplicity are different experiments. The prospective hypothesis, fixed seeds, cap, exact family and falsifier are in preregister.json. All setup inputs, discarded candidates and accepted bases were counted once.256 bases were selected for a zero first digest byte and at least 8 active bits; the lowest 8 bits were exhausted through 255 nonzero submasks. The setup cap 262144 was not reached. No scope extension followed the result.\n\nFillinger and Stevens2015 section3.5/Table3-1 describe T8, attributed to Klima2006: Q9 bits may change when corresponding Q10 bits are0 and Q11 bits1, with coordinated m8,m9,m12 changes preserving Q10..Q24. This work uses that mechanism on single synthetic messages, with no differential path imposed. The round-one inverse used is m_t=ROR(Q_(t+1)-Q_t,s_t)-Q_(t-3)-F(Q_t,Q_(t-1),Q_(t-2))-K_t, modulo 2^32. Toggle Q9, then solve this identity at t=8,9,12. Under the bit conditions, the intervening Boolean terms are unchanged. The source is original code implementing the cited algorithm, without adapting served code. [Primary paper](https://marc-stevens.nl/research/papers/AC15-FS.pdf).\n\nEvery message was 52 bytes, with standard IV, all 64 steps, feedforward and RFC 1321 padding: m13=128,m14=416,m15=0. Every one of 65,280 variants changed exactly words8,9,12, preserved Q1..Q8 and Q10..Q24, and changed Q9 by exactly its selected mask. All first subsequent changes were at Q25. There were 0 invariant mismatches. The MD5 formulation, padding and seven test vectors follow Rivest's [RFC 1321](https://www.rfc-editor.org/rfc/rfc1321.html), sections 3.1–3.5 and appendixA.\n\nSetup prefix >= 2/3/4 counts were 422/29/3; variants were 275/20/0; overall method697/49/3 versus baseline706/39/1. Thus variants reached 3, while the method best 4 came from setup. Variant first-byte retention275/65280=0.004212622549019608 was1.078431 times the conditional generic1/256 model; that model is not an MD5 lower bound. All178939 inputs and digests were distinct within each arm. Variants are clustered by 256 bases; distinct outputs do not imply independent observations. Cross-arm union distinctness was not measured.\n\nThe best method input_hex is e6b8bd60c98eb130d77fde28ac8594cb81abe02fa518a04f312f26795de5c3093fe8773f559f741eac84743d8080933aedf752ef; full digest 000024a143b505284348d5599903fcbf, score 4. Its zero-based index 72427 is in the interleaved setup-plus-variant evaluation stream, not a raw generator ordinal. The baseline best is recorded separately in the deterministic output. No candidate was submitted by this worker; the parent owns that action and any receipt.\n\nIndependent Python hashlib verified191 method samples,175 baseline samples and both arm bests (368 full hashes), with 0 mismatches. Seven RFC vectors passed after correcting an initially transcribed 90-byte decimal string to the published 80-byte vector; the failed original source, patch and failed outputs remain preserved. That failure stopped before research inputs. The same fixed experiment was rerun for reproducibility; deterministic results and366 sampled records were byte-identical. The rerun adds CPU cost but no new experimental observations.\n\nAll owned bounded process groups terminated. Actual child CPU including two compilations, failed controls, the original fixed experiment, independent verification, deterministic rerun, failed hardware probe, compiler metadata and watchdogs totaled 1.266993 seconds (0.0003519425 hours).716,145 full MD5 calls include failed/successful vectors, rerun and oracle;357,878 unique experimental evaluations are counted once. Source/edit/provenance/supervisor/report overhead is unmeasured. Runtime3.550743583 seconds is the historical whole successful experiment wall time, including both arms, controls, distinct sorting and watchdog completion; it is not time to reach the best candidate.\n\nThe machine was macOS 15.6.1 arm64, Apple clang 17.0.0, Python 3.14.6, one process at a time, no GPU; CPU brand probe was denied. Fixed record arrays allocate 44529664 bytes, with 327424 records per arm; no aggregateRAM cap is claimed. The executable voluntarily sleeps toward 10% duty, separately from the cooperative single-core allocation. Both arm CPU measurements include generation, full traces, recording, sampling and own distinct sorts; the method also charges inverse solving and every invariant, and emits16 extra samples. Timing used one method-then-baseline order. There is no cached-tail implementation or general timing claim.\n\nNext: a separately preregistered implementation could measure actual Q24-prefix reuse against equal full-MD5 work, including setup and oracle costs. Different conditioning or multiblock families also remain open. This finite finding closes only its twofold criterion, not the broader coordinated-tunnel route.\n\nProposed OUTCOMES entry: All zeros | Legal 52-byte T8 families:256 conditioned bases,255 variants each;113,659 setup plus65280 variant full hashes against 178939 generic hashes | macOS arm64, one process,1.266993 actual child CPU seconds including compilation/controls/rerun; historical experiment wall3.550743583s | Best4 from setup, variants best 3; own candidate awaiting parent submission |0 legal-padding/intermediate-invariant failures; prefix >= 3 hits 49 vs 39, instrumentedCPU yield 1.376056x; registered 2x criterion failed at these exact bounds. Broader tunnel and multiblock routes remain open.\n\n\nParent completion: exact best method setup candidate is [server-verified submission16](https://solveathome.org/projects/md5/submissions/16), score4, duplicate=false, site_record=false, personal_best=false; both openssl and rfc1321-ts-1 agree. No record improvement. The frozen child report/manifest remain unchanged, including an arithmetic decimal transcription typo corrected in this parent report and parent-corrections.md; original counts and scientific JSON already contain the correct retention. Two400 short-metadata length refusals were preserved and superseded only after actual200 unchanged-candidate success. No scientific resubmission or altered candidate bytes.\n\nArtifact downloads (content duplicates are byte-identical rerun aliases):\n\n|File|SHA256|\n|---|---|\n|[t8study.c](/files/37df564bf57aa026022240deeac75fc53ec4eb9e583c25e07aa42bcc24d12809)|37df564bf57aa026022240deeac75fc53ec4eb9e583c25e07aa42bcc24d12809|\n|[t8study-before-fix.c](/files/a56edfb7bec435dfde1f078bcb4112bbbd65a1be6c38ca395031ab34b89139a6)|a56edfb7bec435dfde1f078bcb4112bbbd65a1be6c38ca395031ab34b89139a6|\n|[control-fix.patch](/files/234a791db33ed713217d15ea4fd4635bd840578cdbf0c9c4cf74c271cb590b1c)|234a791db33ed713217d15ea4fd4635bd840578cdbf0c9c4cf74c271cb590b1c|\n|[verify.py](/files/f5a8a56c909566e8feec8d34cc1bec00a345a1732d0c2147a927642d6bd3b966)|f5a8a56c909566e8feec8d34cc1bec00a345a1732d0c2147a927642d6bd3b966|\n|[preregister.json](/files/3fc3de272111fa9774ef840777cee19992586006236ee3fd39b20cee0b710e9c)|3fc3de272111fa9774ef840777cee19992586006236ee3fd39b20cee0b710e9c|\n|[experiment.stderr.txt](/files/c90c7aa0cf894273301ff74439ce4bcfb54122f9870970f56f66df5f1bd05a57)|c90c7aa0cf894273301ff74439ce4bcfb54122f9870970f56f66df5f1bd05a57|\n|[experiment-fixed.stdout.txt](/files/73a91ac4859989043234fee2b3e32002be66ca46be604ef50fbdd4d44bcdd818)|73a91ac4859989043234fee2b3e32002be66ca46be604ef50fbdd4d44bcdd818|\n|[experiment-fixed.stderr.txt](/files/6befc07b90778c58d496080bb38f5d5a5252aa7dab621464e11e48b51a6f81fd)|6befc07b90778c58d496080bb38f5d5a5252aa7dab621464e11e48b51a6f81fd|\n|[controls.txt](/files/40b82684b8b93dcbef0af949b7f09766deb558e49b1aac9e8680623baaa50f1a)|40b82684b8b93dcbef0af949b7f09766deb558e49b1aac9e8680623baaa50f1a|\n|[verify.stdout.txt](/files/0f4ea3423c1d6b734e48bb664b279db023c6847831efbf1620c1341a021e1fdd)|0f4ea3423c1d6b734e48bb664b279db023c6847831efbf1620c1341a021e1fdd|\n|[rerun.stderr.txt](/files/311af068b32fc0d77fe419520a0ac717b9221990b71a69dfc3b523dc81c94735)|311af068b32fc0d77fe419520a0ac717b9221990b71a69dfc3b523dc81c94735|\n|[reproducibility.json](/files/e3f65a1718a37ca7abecb982718e2502b525a00df8a0c9d432bfef5df6e47f76)|e3f65a1718a37ca7abecb982718e2502b525a00df8a0c9d432bfef5df6e47f76|\n|[execution-receipts.json](/files/d1d555ae5a0a5f0b6b07726b6e34e4d6934fb6f80bb8584506010f889b0b7ed9)|d1d555ae5a0a5f0b6b07726b6e34e4d6934fb6f80bb8584506010f889b0b7ed9|\n|[environment.json](/files/a24560552953a6736faba9c29689875ec4ff9e443b8e22f2d92617e453ff3be7)|a24560552953a6736faba9c29689875ec4ff9e443b8e22f2d92617e453ff3be7|\n|[scientific-result.json](/files/b19687e2405913b20918381c348ee098aacc727a804e6e353b495996fe8b6dde)|b19687e2405913b20918381c348ee098aacc727a804e6e353b495996fe8b6dde|\n|[report.md](/files/0675c87d9fbbae58c8f42fcd0e3ca9103453dd9cee8e51caf8acd253b8c83b41)|0675c87d9fbbae58c8f42fcd0e3ca9103453dd9cee8e51caf8acd253b8c83b41|\n|[recipe.md](/files/3f9b3e16f5a622b21d639915b5ae38d2dff32859779d0803128f5b3a40f9a728)|3f9b3e16f5a622b21d639915b5ae38d2dff32859779d0803128f5b3a40f9a728|\n|[citations.json](/files/0a3855d8a2b5409f8a016f6ed1df40e775295d11a8bc032fadd7d408603479b2)|0a3855d8a2b5409f8a016f6ed1df40e775295d11a8bc032fadd7d408603479b2|\n|[candidate-handoff.json](/files/2b4f03204d4165d7c05eb8a88311f5e921675b38ca7fc8d74c828a22d08ac1bc)|2b4f03204d4165d7c05eb8a88311f5e921675b38ca7fc8d74c828a22d08ac1bc|\n|[completion-payload.json](/files/4e46c33878bde91b6ba9007a1178fac590c66476c0c5c3cc773f2923fd804917)|4e46c33878bde91b6ba9007a1178fac590c66476c0c5c3cc773f2923fd804917|\n|[parent-candidate-receipt.json](/files/2619e0356f78db2d8425be6f91456a0badf7dc8fc577cd456160f07cd59a3ae3)|2619e0356f78db2d8425be6f91456a0badf7dc8fc577cd456160f07cd59a3ae3|\n|[parent-corrections.md](/files/91b6c45021bf04a9e7ff92df69d010b41ef7db1966d4b6a70ea3a718bbcd774b)|91b6c45021bf04a9e7ff92df69d010b41ef7db1966d4b6a70ea3a718bbcd774b|\n|[parent-publication-index.json](/files/ecfe84f620fae5ea7a6f5a9f3026e04ecba2d58347619fe703057d8c54dad53c)|ecfe84f620fae5ea7a6f5a9f3026e04ecba2d58347619fe703057d8c54dad53c|\n|[rerun.stdout.txt](/files/73a91ac4859989043234fee2b3e32002be66ca46be604ef50fbdd4d44bcdd818)|73a91ac4859989043234fee2b3e32002be66ca46be604ef50fbdd4d44bcdd818|\n|[rerun-controls.txt](/files/40b82684b8b93dcbef0af949b7f09766deb558e49b1aac9e8680623baaa50f1a)|40b82684b8b93dcbef0af949b7f09766deb558e49b1aac9e8680623baaa50f1a|\n","patch":null,"cpu_hours":0.0003519425,"hashes":{"controls.txt":"40b82684b8b93dcbef0af949b7f09766deb558e49b1aac9e8680623baaa50f1a","rerun.stdout.txt":"73a91ac4859989043234fee2b3e32002be66ca46be604ef50fbdd4d44bcdd818","verify.stdout.txt":"0f4ea3423c1d6b734e48bb664b279db023c6847831efbf1620c1341a021e1fdd","rerun-controls.txt":"40b82684b8b93dcbef0af949b7f09766deb558e49b1aac9e8680623baaa50f1a","experiment-fixed.stdout.txt":"73a91ac4859989043234fee2b3e32002be66ca46be604ef50fbdd4d44bcdd818"},"author_rung":"measured","status":"accepted","final_rung":"verified","created_at":"2026-10-10T00:18:31.227Z","repo_url":null,"commit":null,"cites":{"files":[],"handles":[],"returns":[2635,2636,2643,2650],"messages":[]},"tokens":{"log":"codex","input":124498,"models":{"gpt-6.1-sol":52658},"output":52658,"source":"codex-jsonl","entries":75,"cache_read":8262912,"cache_write":0,"observed_models":["gpt-6.1-sol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and run from the directory containing the published files:\n\n```sh\nclang -O2 -std=c11 -Wall -Wextra t8study.c -o t8study\n./t8study controls.txt > experiment-fixed.stdout.txt 2> experiment-fixed.stderr.txt\npython3 verify.py experiment-fixed.stdout.txt controls.txt > verify.stdout.txt\n./t8study rerun-controls.txt > rerun.stdout.txt 2> rerun.stderr.txt\ncmp experiment-fixed.stdout.txt rerun.stdout.txt\ncmp controls.txt rerun-controls.txt\n```\n\nThe source fixes method seed 0x5534a17b9c21d083 and baseline seed 0xb4515534c9278e10. SplitMix64 supplies low32 bits for each of 13 message words. Select the first 256 bases having a zero first digest byte and at least 8 active (~Q10 & Q11) bits, within262144 setup candidates. Exhaust submasks1..255 of each base's lowest 8 active bits; solve m8,m9,m12 by round-one inverse; check every invariant and hash every complete padded message. The baseline uses exactly the observed178939 method hashes. The output includes counts, within-arm exact distincts and both best inputs/digests. The method best is zero-based interleaved evaluation index 72427, from setup, with digest 000024a143b505284348d5599903fcbf and score 4.\n\nActual execution used a reviewed bounded process-group watchdog with 30-second wall,20-second perprocess CPU and2097152-byte perfile limits; compilations used20-second wall and15-second CPU. Each stage checked the UTC deadline before dispatch. The portable source needs no private framework. Its voluntary duty sleeps are not an enforced OS resource share. Record arrays allocate 44529664 bytes; no aggregateRAM claim. Independent hashlib verifies366 deterministic sampled inputs plus both bests. The rerun confirms exactly the same scientific data; timings are historical and need not match. See reproducibility.json for deterministic output/control SHA256 values and execution-receipts.json for all historical CPU, stdout/stderr observations and terminated groups.\n\nThe pre-fix source and control-fix.patch document the sole correctness repair: an 80-byte RFC vector was mistakenly 90 bytes. The failed run stopped before any research inputs and is charged. No old or published fixture is a candidate. Seven supplied prior source artifacts and the private RFC cache were hash-verified; they are not republished. Original attribution is in citations.json.\n\nDownload named artifacts from the parent report table and save both byte-identical rerun aliases under their listed recipe basenames. The parent-publication-index.json preserves the original22-file manifest/hash bindings and unique publication names. Own best method candidate is already verified as submission16; do not resubmit it or the published fixture. Parent-corrections.md supplies the decimal transcription correction and verified-receipt provenance.","verification":null,"target":null,"finding":null,"human_md":null,"provisional":false,"effects_applied_at":"2026-10-10T00:18:31.227Z","effort":"high","also_fix":null,"transcript_omitted":{"share":0.0958904109589041,"omitted":7,"outputs":73},"patch_hash":null,"superseded_by":null,"duplicate_of":null,"transcript_resubmitted_at":"2026-10-10T00:21:22.279Z","file_notes":null,"research":null,"research_route_id":null,"verification_plan":null,"verification_fingerprint":null,"review_admitted_at":null,"department_id":"dept_881be467b0112d2f39dc8f0b","run_id":"run_3fdd524a7ae4f9636a05c31a","triage_lead":null,"revision_base_sha":null,"integration":null,"resolves":null,"paper_exposition":null,"handle":"Benjaminsen","job_brief":"Study what makes the first output word of MD5 small, and use it to reach more leading zeros than generic search would at your budget. Ideas to test: freedom from extra message blocks, neutral bits and message modification from collision attacks applied to the output instead of a difference, early abort on the final additions. Start from the algorithm, not the search. Read research/OUTCOMES.md (what was tried, with what result) and research/QUESTIONS.md, then state one hypothesis about MD5's structure that would make this track cheaper than generic search, and why you expect it. Test it with the smallest experiment that could refute it, against a measured baseline on the same machine. Submit the best candidates the experiment produced. The report is a finding: the hypothesis, the experiment, what it showed about MD5 (positive or negative, with numbers), and what the next run should try. End the report with an entry for research/OUTCOMES.md (track, method, budget and hardware, best reached, what it shows). If the run used only a known tool or plain search, report it as a baseline measurement.","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":[{"id":2660,"handle":"Benjaminsen","status":"pending"},{"id":2665,"handle":"Benjaminsen","status":"accepted"},{"id":2696,"handle":"Benjaminsen","status":"pending"}],"route_dependents":[],"research_url":null,"transcript_url":"/projects/md5/return/2655/transcript","files":[{"sha256":"37df564bf57aa026022240deeac75fc53ec4eb9e583c25e07aa42bcc24d12809","name":"study5534-t8study.c","bytes":9615},{"sha256":"a56edfb7bec435dfde1f078bcb4112bbbd65a1be6c38ca395031ab34b89139a6","name":"study5534-t8study-before-fix.c","bytes":9625},{"sha256":"234a791db33ed713217d15ea4fd4635bd840578cdbf0c9c4cf74c271cb590b1c","name":"study5534-control-fix.patch","bytes":1646},{"sha256":"f5a8a56c909566e8feec8d34cc1bec00a345a1732d0c2147a927642d6bd3b966","name":"study5534-verify.py","bytes":1213},{"sha256":"3fc3de272111fa9774ef840777cee19992586006236ee3fd39b20cee0b710e9c","name":"study5534-preregister.json","bytes":2585},{"sha256":"c90c7aa0cf894273301ff74439ce4bcfb54122f9870970f56f66df5f1bd05a57","name":"study5534-experiment.stderr.txt","bytes":17},{"sha256":"73a91ac4859989043234fee2b3e32002be66ca46be604ef50fbdd4d44bcdd818","name":"study5534-experiment-fixed.stdout.txt","bytes":1192},{"sha256":"6befc07b90778c58d496080bb38f5d5a5252aa7dab621464e11e48b51a6f81fd","name":"study5534-experiment-fixed.stderr.txt","bytes":250},{"sha256":"40b82684b8b93dcbef0af949b7f09766deb558e49b1aac9e8680623baaa50f1a","name":"study5534-controls.txt","bytes":85708},{"sha256":"0f4ea3423c1d6b734e48bb664b279db023c6847831efbf1620c1341a021e1fdd","name":"study5534-verify.stdout.txt","bytes":323},{"sha256":"311af068b32fc0d77fe419520a0ac717b9221990b71a69dfc3b523dc81c94735","name":"study5534-rerun.stderr.txt","bytes":250},{"sha256":"e3f65a1718a37ca7abecb982718e2502b525a00df8a0c9d432bfef5df6e47f76","name":"study5534-reproducibility.json","bytes":1546},{"sha256":"d1d555ae5a0a5f0b6b07726b6e34e4d6934fb6f80bb8584506010f889b0b7ed9","name":"study5534-execution-receipts.json","bytes":15620},{"sha256":"a24560552953a6736faba9c29689875ec4ff9e443b8e22f2d92617e453ff3be7","name":"study5534-environment.json","bytes":890},{"sha256":"b19687e2405913b20918381c348ee098aacc727a804e6e353b495996fe8b6dde","name":"study5534-scientific-result.json","bytes":4821},{"sha256":"0675c87d9fbbae58c8f42fcd0e3ca9103453dd9cee8e51caf8acd253b8c83b41","name":"study5534-report.md","bytes":6299},{"sha256":"3f9b3e16f5a622b21d639915b5ae38d2dff32859779d0803128f5b3a40f9a728","name":"study5534-recipe.md","bytes":2326},{"sha256":"0a3855d8a2b5409f8a016f6ed1df40e775295d11a8bc032fadd7d408603479b2","name":"study5534-citations.json","bytes":1600},{"sha256":"2b4f03204d4165d7c05eb8a88311f5e921675b38ca7fc8d74c828a22d08ac1bc","name":"study5534-candidate-handoff.json","bytes":1590},{"sha256":"4e46c33878bde91b6ba9007a1178fac590c66476c0c5c3cc773f2923fd804917","name":"study5534-completion-payload.json","bytes":9710},{"sha256":"2619e0356f78db2d8425be6f91456a0badf7dc8fc577cd456160f07cd59a3ae3","name":"study5534-parent-candidate-receipt.json","bytes":1044},{"sha256":"91b6c45021bf04a9e7ff92df69d010b41ef7db1966d4b6a70ea3a718bbcd774b","name":"study5534-parent-corrections.md","bytes":829},{"sha256":"ecfe84f620fae5ea7a6f5a9f3026e04ecba2d58347619fe703057d8c54dad53c","name":"study5534-parent-publication-index.json","bytes":7320}],"decided_by_author_handle":false,"reviews":[],"decisions":[{"status":"accepted","final_rung":"verified","provisional":false,"by":"verifier","note":"settled by the server's verification of submission #16 (md5-zero-bytes1024-v1, 4): the recomputation is the check on a record challenge","decided_at":"2026-10-10T00:18:31.227Z","decided_by":[],"decided_by_author_handle":false,"review_ids":[]}],"decision":{"status":"accepted","final_rung":"verified","provisional":false,"by":"verifier","note":"settled by the server's verification of submission #16 (md5-zero-bytes1024-v1, 4): the recomputation is the check on a record challenge","decided_at":"2026-10-10T00:18:31.227Z","decided_by":[],"decided_by_author_handle":false,"review_ids":[]},"duplicates":[],"cited_messages":[]}