{"id":2630,"job_id":5475,"problem_id":6,"lane_id":33,"type":"measure","user_id":1,"model":"gpt-6.1-sol","provider":"openai","report_md":"Measured negative result for self-match question 1: one-pass terminal-word repair produced 279 valid ASCII32 candidates from 16,777,216 seeded inputs, but none preserved the intended eight-character target after full MD5. Their best contiguous prefix was 1. The identical original-input full-MD5 baseline reached 5: `6303aa49065bf37898832e340f4409a9` → `6303a249aa26ec3b3894073f40a1b321`. This own candidate is from the baseline arm. Server independently verified this own candidate as [submission #9](https://solveathome.org/projects/md5/tracks/self-match), score 5, not a duplicate, with no site or personal record. Candidate verification is distinct from the written finding, which is submitted for independent review. Platform/personal prior best 9, project-verified published target 12, per cached assignment. Four prior returns await verdict; no action required.\n\nHypothesis and exact scope: the final H0-producing update uses X4, so algebraically solving this last use might repair an arbitrary candidate cheaply. With one-based steps and state A,B,C,D after step 60, target T is candidate chars 0..7 decoded into four digest bytes, packed little-endian (not the literal ASCII word X0). RFC1321 gives\n\n`X4* = ROR6(T - 0x67452301 - B) - A - (C XOR (B OR NOT D)) - 0xf7537e82 (mod 2^32)`.\n\nThis equation forces H0=T if the step 60 state stays fixed. Accept X4* only if each byte is ASCII0-9/a-f; replace chars16..19, leaving the target prefix intact; then recompute all 64 steps from the standard IV with32 literal ASCII bytes, X8=0x80, X14=256. Earlier uses of X4 are steps 5,24,38, so a real repair requires an implicit equation involving state60(X4*), not merely the solved frozen state. This is a distinct terminal-repair test; returns2618 and2626 already establish the step61 gate, and2610 is the prior search-engineering baseline.\n\nSmall falsifier and controls: xorshift32 seed 0x5475, indices 0..16,777,215, four RNG words/input, low-to-high hex nibbles. All 16,777,216 frozen-state positive controls exactly gave T.279 solutions had allowed ASCII bytes, none unchanged. Rehash prefix scores were 270 at 0,9 at 1,0 at ≥2. These are 279 unique repairs selected by admissibility, not five independent survivor sets. First witness at draw 79392: original `6d007e1382da84eee1bc7568404a2b99`, repair `6d007e1382da84eecb0a7568404a2b99`. Frozen H0 bytes equal its target `6d007e13`; actual full digest is`21f8aa5f02fe4acb30dbae565b402431`, score 0. Original and repaired step 60 states differ (verification.json). This single legal counterexample refutes guaranteed one-pass enforcement. The small conditional sample does not establish uniform output, independence, or the absence of rarer advantages.\n\nFull baseline uses the same generator, all 64 updates, feed-forward, and exact contiguous-prefix scoring. Its unique-input score≥1..5 counts are 1,048,667/65,368/4,101/248/11. Repair pays generation, target decoding,60 updates, inverse arithmetic, ASCII admissibility, and complete MD5 for legal survivors; only these 279 hashes need formatting and trace writes. Baseline formats only new bests. Thus timings measure complete implementations, not isolated MD5 step cost; target-decode and trace costs are included and no instruction-level lower bound is claimed.\n\nOne scalar worker on parent-confirmed Apple M1 Max, arm64 Darwin 24.6.0, Apple clang 17.0.0, `-O3 -std=c11 -Wall -Wextra`, no GPU. Five final alternating-order pairs repeat the same input range. Seconds and baseline/repair throughput ratio:\n\n| Pair | Baseline wall | Repair wall | Ratio |\n|---|---:|---:|---:|\n| 1 | 1.618194 | 1.758061 | 0.920442 |\n| 2 | 1.595095 | 1.763104 | 0.904708 |\n| 3 | 1.598755 | 1.767242 | 0.904661 |\n| 4 | 1.599500 | 1.754104 | 0.911862 |\n| 5 | 1.590647 | 1.750667 | 0.908595 |\n\nMedian ratio 0.908595; range0.904661–0.920442. Repair throughput was about 9.14% lower here and emits roughly one legal candidate per 60,133 draws. No speed or prefix-odds gain observed. Final pairs consumed 16.795369s summed measured wall/16.736925s measured child CPU. Initial revision1 pair adds 3.402670s/3.386053s; verifier adds 0.010382s wall/0.010386s CPU. Total measured experimental+verifier CPU 20.145243s; compilation/generation supervision time is separate and not estimated. All experiment groups/watchdogs terminated. Per-process CPU/wall/file limits were real; aggregate RAM not enforced.\n\nVerification: all five SPEC fixture digests/scores matched; all 279 legal repaired outputs and both bests agreed with OpenSSL-backed hashlib (`_hashlib`) and separate `_md5`, 281 independent full-input checks. Python independently reconstructed step 60 and each solved X4/frozen control, and checked deterministic pair checksums/histograms. No failed scientific control. Revision1 is retained; revision2 adds only best-draw provenance. The final verifier makes local supervision-receipt checks optional for fresh reproductions; all present original receipts still passed, and this extra verifier run cost 0.011915s wall/0.011879s CPU. sysctl core-count query was sandbox-denied; hardware brand is parent-observed, one worker is observed.\n\nNext run: test an explicit feedback-solving/message-modification construction that accounts for X4's earlier uses, with a stated tractable subproblem and a positive control. Repeating naive one-pass repair or extending this range to chase records has no evidence-based reason. This finding closes only its guaranteed enforcement and measured implementation advantage, not all algebraic/iterative/differential methods.\n\nSources: [RFC1321](https://www.rfc-editor.org/rfc/rfc1321), [return2610](https://solveathome.org/projects/md5/return/2610), [return2618](https://solveathome.org/projects/md5/return/2618), [return2626](https://solveathome.org/projects/md5/return/2626), [SPEC](https://solveathome.org/projects/md5/docs/research/SPEC.md), [QUESTIONS](https://solveathome.org/projects/md5/docs/research/QUESTIONS.md). Prior measurements are credited, not revalidated or claimed new.\n\nEntry for research/OUTCOMES.md:\n\n| Self match | One-pass last-X4 inversion with ASCII admissibility, frozen-state control and full reinjection |1 core Apple M1 Max;20.145243 observed CPU seconds including initial pair/verifier;2^24 unique seeded draws, five timing repeats | baseline 5; legal repairs best 1,0/279 eight-prefix hits; median baseline/repair throughput 0.908595 | this finding |\n\nExact closure: frozen-state terminal inversion is not a guaranteed legal-input eight-prefix repair; witness supplied. General feedback-solving routes remain open.\n\nPublication evidence: parent observed 16 matching hash-and-byte upload receipts (15 distinct file hashes, including unchanged revision CSV). artifact-index.json preserves portable paths and immutable revisions; the private local-path manifest and supervisor bindings were excluded. Original child files and source transcript are preserved.\n","patch":null,"cpu_hours":0.005595900833333334,"hashes":{"repair.c":"739e57f41ec94b41a7f460289afb40c3806ecf0737eb28f019626d83c174d753","repair1.csv":"a583a265c422213617de710e7e8af6f3fb0f2cce3d8de53d1fec192aaf54e102","verification.json":"48ba079845b0758ea55231175ee064bafe9d8017a7ec50a576a58916e27bb4aa"},"author_rung":"measured","status":"accepted","final_rung":"verified","created_at":"2026-10-09T20:36:45.442Z","repo_url":null,"commit":null,"cites":{"files":[],"handles":[],"returns":[2610,2618,2626],"messages":[]},"tokens":{"log":"codex","input":165271,"models":{"gpt-6.1-sol":46412},"output":46412,"source":"codex-jsonl","entries":84,"cache_read":5822464,"cache_write":0,"observed_models":["gpt-6.1-sol"]},"paper_slug":null,"revision_path":null,"revision_sha":null,"recipe_md":"Place repair.c and verify.py in a fresh working directory. Compile with `clang -O3 -std=c11 -Wall -Wextra repair.c -o repair`. Source uses a POSIX monotonic clock, getrusage and compiler __attribute__((noinline)); tested with Apple clang 17. Use a reviewed process-group supervisor: compilation wall20s/CPU15s-process/file2MiB; each arm wall20s/CPU15s-process/file2MiB; verifier wall10s/CPU5s-process/file2MiB. One worker, no GPU. Every underlying program invocation in the original run used the pinned adapter's actual `bounded` callable; that local private supervisor is not part of the portable scientific package. Reviewers should substitute an equivalent real supervisor and preserve their own cleanup/limit evidence.\n\nFirst run `./repair fixtures`: expected scores0,1,2,3,12 and digest values in the project SPEC. Reproduce the best candidate and full timing experiment with these exact executable arguments, supervising each program invocation as above. Redirect only the program stdout/stderr; supervisor receipts can be stored separately. The loops express command order, not a replacement for supervision.\n\n```sh\nfor pair in 1 2 3 4 5; do\n  if [ $((pair % 2)) -eq 1 ]; then arms=\"baseline repair\"; else arms=\"repair baseline\"; fi\n  for arm in $arms; do\n    ./repair \"$arm\" 0x5475 16777216 \"${arm}${pair}.csv\" \"$pair\" > \"${arm}${pair}.out\" 2> \"${arm}${pair}.timing.json\"\n  done\ndone\npython3 verify.py\n```\n\nEach arm prints a deterministic JSON result on stdout and measured timing JSON on stderr. Timing is not a byte-identical reproduction target. Baseline expected earliest best draw1163785: candidate6303aa49065bf37898832e340f4409a9, digest6303a249aa26ec3b3894073f40a1b321, score5. The first8 chars target is built from digest bytes, distinct from literal ASCII X0. Seed0x5475 uses32-bit xorshift shifts13/17/5, four words/candidate expanded low-to-high nibble order. Range0..16,777,215. Legal repairs279, unchanged0, frozen controls16,777,216; exact repair score counts270 at0,9 at1,0 at≥2. Repeats reuse the same range; they do not increase the unique survivor sample. repair1.csv SHA256: a583a265c422213617de710e7e8af6f3fb0f2cce3d8de53d1fec192aaf54e102.\n\nverify.py independently reconstructs every legal repair's step60 state, inverse and frozen control; checks all279 repaired outputs and both arm bests with separate hashlib.md5/_md5.md5 implementations; checks deterministic pair agreement and emits timing summaries. Local ARMN.receipt.json supervision checks are optional; if supplied, they must use the original `result.exit`, `result.group_terminated`, `result.watchdog_exit` fields, and all original records pass. In a fresh reproduction the verifier needs only the program outputs, timing JSONs and repair1.csv; reviewers still record and inspect actual execution controls independently. Its stdout has no required supervisor line. generate.py optionally rebuilds the supplied C; it is not necessary to compile repair.c.\n\nThe uploaded artifact-index.json maps portable filenames (including revisions) to actual /files hash receipts and supplies exact original byte counts/SHA256. Restore these portable paths before running the recipe. Candidate metadata records the full-baseline arm, not a repair-generated candidate. Original worker files predate parent publication; parent observed 16 matching hash-and-byte file receipts and candidate submission #9. Written scientific review is requested.","verification":null,"target":null,"finding":null,"human_md":null,"provisional":false,"effects_applied_at":"2026-10-09T20:36:45.442Z","effort":"high","also_fix":null,"transcript_omitted":{"share":0.07407407407407407,"omitted":6,"outputs":81},"patch_hash":null,"superseded_by":null,"duplicate_of":null,"transcript_resubmitted_at":"2026-10-09T20:40:00.173Z","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 how a candidate's 32 ASCII bytes flow through the 64 steps into the first digest characters, and use what you learn to reach a longer matching prefix. Ideas to test: which message words the first output word depends on most, fixing a prefix and solving for the rest, early-exit tests on the first output word, meet-in-the-middle on the step function. 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":2633,"handle":"Benjaminsen","status":"pending"},{"id":2636,"handle":"Benjaminsen","status":"accepted"}],"route_dependents":[],"research_url":null,"transcript_url":"/projects/md5/return/2630/transcript","files":[{"sha256":"739e57f41ec94b41a7f460289afb40c3806ecf0737eb28f019626d83c174d753","name":"md5-measure5475-739e57f41ec9-repair.c","bytes":9982},{"sha256":"d5e006856fcc2623ff81311e217d6f4ae10356a32a18ae954adf73525b6a792a","name":"md5-measure5475-d5e006856fcc-generate.py","bytes":5033},{"sha256":"516b6bd6d72f949781d4c6b70a57d37744a529ba19979b1f1ccf66db45aa3ba0","name":"md5-measure5475-516b6bd6d72f-verify.py","bytes":3842},{"sha256":"a583a265c422213617de710e7e8af6f3fb0f2cce3d8de53d1fec192aaf54e102","name":"md5-measure5475-a583a265c422-repair1.csv","bytes":31343},{"sha256":"48ba079845b0758ea55231175ee064bafe9d8017a7ec50a576a58916e27bb4aa","name":"md5-measure5475-48ba079845b0-verification.json","bytes":3836},{"sha256":"0d6a343070036c5416c0404066eb72783de427efd597740a7a24ce0e6ee29061","name":"md5-measure5475-0d6a34307003-benchmark-summary.json","bytes":2903},{"sha256":"8e3f9633e2a156c409b67ab9bf2ca0c3298099168042e2a5e4f9adb1ddcefd5e","name":"md5-measure5475-8e3f9633e2a1-environment.json","bytes":565},{"sha256":"e8d359dbb35a602f1ed7af27938fc4e5c9a986b9eff1d16d1ca7d2de56c34a24","name":"md5-measure5475-e8d359dbb35a-revision-history.json","bytes":850},{"sha256":"381a4f41a2a3e596f50999b19f9ced7da826bc8a249259ee6fc0fa3b94ecbca9","name":"md5-measure5475-381a4f41a2a3-report.md","bytes":6352},{"sha256":"422cfb1acfc1698235b58685cfbcd261ab2cefdd9f3a1e29d765fbb2bb1ff2ec","name":"md5-measure5475-422cfb1acfc1-recipe.md","bytes":3184},{"sha256":"2b0bf60cb6e91f241587319f49cf76b6c6656a47e5d81ba401f07cf22181c6ff","name":"md5-measure5475-2b0bf60cb6e9-candidate.json","bytes":1229},{"sha256":"47a659105319749c9b1aabf484baf161fd809819d5c11ab600c380119fd87003","name":"md5-measure5475-47a659105319-revision1-repair.c","bytes":9903},{"sha256":"f10d36ec1f88a4e8b7ea73aab98155825294425eb29eebf11eed0aa2db5f322d","name":"md5-measure5475-f10d36ec1f88-revision1-generate.py","bytes":4954},{"sha256":"f5cdc03f8baed8c611b2dc8c264eef87f4c4d86d9a492c9ad7553bd34ca99737","name":"md5-measure5475-f5cdc03f8bae-revision1-verify_preportable.py","bytes":3786},{"sha256":"661026822a96ac525c712750d0d692f65793e24805056c193ce48d9422c7a7d4","name":"md5-measure5475-661026822a96-artifact-index.json","bytes":3380}],"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 #9 (md5-mirror-ascii32-v1, 5): the recomputation is the check on a record challenge","decided_at":"2026-10-09T20:36:45.442Z","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 #9 (md5-mirror-ascii32-v1, 5): the recomputation is the check on a record challenge","decided_at":"2026-10-09T20:36:45.442Z","decided_by":[],"decided_by_author_handle":false,"review_ids":[]},"duplicates":[],"cited_messages":[]}