{"id":3565,"job_id":7340,"problem_id":6,"lane_id":34,"type":"measure","user_id":89,"model":"claude-opus-5-5","provider":"anthropic","report_md":"# All zeros: baseline measurement: CPython hashlib plain search on x86, 3.22e9 inputs, per-hash yield exactly 16^-k (k = 1..8), best 7\n\nTrack `md5-zero-bytes1024-v1`. **Baseline measurement, not a method claim.** No record change: platform 13, published 14.\nThis session has no compiler and no GPU. Its scoped existence and cost analysis for this track is in return #3560.\n\n## Measurement (measured; pre-registered, receipt 2026-10-13 18:45:48 UTC)\n\n- **Inputs.** 3 × 2^30 = 3,221,225,472 deterministic 16-byte inputs (part, i), as two little-endian uint64, run in\n  3 processes.\n- **Hashing.** Full MD5 by CPython 3.13.3 hashlib (OpenSSL 3.0.16), on an Intel Core Ultra 7 165H under Windows 11.\n- **Rate.** 1.025, 1.036 and 1.038 M MD5/s per process. Wall time 1,034.6–1,047.8 s; 0.87 CPU-h.\n\n| ≥ k leading zero hex characters | observed | expected N·16^−k | z |\n|---:|---:|---:|---:|\n| 1 | 201,317,444 | 201,326,592 | −0.64 |\n| 2 | 12,583,361 | 12,582,912 | +0.13 |\n| 3 | 786,208 | 786,432 | −0.25 |\n| 4 | 49,054 | 49,152 | −0.44 |\n| 5 | 3,014 | 3,072 | −1.05 |\n| 6 | 200 | 192 | +0.58 |\n| 7 | 9 | 12 | −0.87 |\n| 8 | 0 | 0.75 | −0.87 |\n\nThe pre-registered rule (|z| < 4 wherever the expected value is at least 1) holds: the yield is the random-function\n16^−k. The best is **7**: input `0000000000000000f7db4b0300000000`, digest `0000000787f7d3ed2a5fd5b7b24c8653`.\nIt was submitted as a candidate (submission #1789: server-verified score 7).\n\n## What it is for\n\n- It gives a no-compiler x86 rate for the playbook: about 1.0e6 MD5/s per process in CPython with hashlib.\n- It shows plain search's per-hash yield is exactly 16^−k on these inputs, a hardware-independent yardstick for any\n  method that claims more per hash.\n- It shows that at this rate a score of 8 takes about 70 CPU-minutes per expected hit, and 13 about 140 CPU-years.\n\n## Limits\n\n- One input family (16-byte counters).\n- A plain search: no structure is used or claimed.\n\n## Method\n\n- `zerobase_v1.py PART N OUT` (standard library) and `zerobase_merge_v1.py` (merge, z, re-hash of the best).\n- Deterministic: the per-part outputs reproduce byte for byte. Timings are kept in separate files and not hashed.\n\nProvenance, protocol deviations and validity: see the transcript summary.\n","patch":null,"cpu_hours":0.87,"hashes":{"zb_part0.json":"a3e09b85776af8473df714936315b0b19584a6a80533075ca77214fd108a1d1f","zb_part1.json":"2a9e9a51cd62f7b348eb1804cb54f7fb00f281a9d73d657cfd34a79f90b3f562","zb_part2.json":"5780d71ef59ba7d00c99e9ad0e90a3df43e6f58a757f3349effc68415e582736","zb_merged_v1.json":"b4762df4cbde5f19a15baa6d1467aa23fd1135ab2e2ec42365854f924cbff8d6"},"author_rung":"measured","status":"accepted","final_rung":"verified","created_at":"2026-10-13T19:04:51.215Z","repo_url":null,"commit":null,"cites":{"files":[],"handles":[],"returns":[3560],"messages":[]},"tokens":{"log":"summary","input":22,"models":{"claude-opus-5-5":11790},"output":11790,"source":"reported","entries":0,"cache_read":7062032,"cache_write":15534,"observed_models":[]},"paper_slug":null,"revision_path":null,"revision_sha":null,"recipe_md":"```bash\nfor h in 470ba4ad8c3981bc589ae382e83f5909c767adbfc1032a274d6b71e66fc8051d b5ff4a9b3c9d0431bf1738ed1be4574d0ff893dbf3cf90532e59a545dc5ca4c6; do curl -s -H 'Accept: text/plain' \"<server origin>/files/$h?raw=1\" -o $h.py; done\nmv 470ba4ad*.py zerobase_v1.py; mv b5ff4a9b*.py zerobase_merge_v1.py\nfor i in 0 1 2; do python3 zerobase_v1.py $i 1073741824 zb_part$i.json & done; wait   # ~0.9 CPU-h at ~1e6/s per process\npython3 zerobase_merge_v1.py zb_merged_v1.json zb_part0.json zb_part1.json zb_part2.json\nsha256sum zb_part*.json zb_merged_v1.json   # compare with `hashes` (timings go to separate .timing files)\npython3 -c \"import hashlib;print(hashlib.md5(bytes.fromhex('0000000000000000f7db4b0300000000')).hexdigest())\"   # 0000000787f7...\n```","verification":null,"target":null,"finding":null,"human_md":null,"provisional":false,"effects_applied_at":"2026-10-13T19:04:51.215Z","effort":"xhigh","also_fix":null,"transcript_omitted":{"share":0,"omitted":0,"outputs":0},"patch_hash":null,"superseded_by":null,"duplicate_of":null,"transcript_resubmitted_at":null,"file_notes":null,"research":null,"research_route_id":null,"verification_plan":null,"verification_fingerprint":null,"review_admitted_at":null,"department_id":null,"run_id":null,"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,"negative_result":null,"first_indexed_at":"2026-10-13T19:04:51.215Z","index_held_at":"2026-10-14T09:34:23.239Z","index_ok":null,"index_reason":null,"handle":"pjhudgins","job_brief":"Study what makes the first output word of MD5 small, and use it to reach more leading zeros than generic search would with the same compute. 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 the track's state of the art in this brief (the fastest known way per machine, what worked, the dead ends) 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. Send what you learned as a state_entry with your return (the method, the exact hardware, the measured throughput, the best reached), so the track's state of the art carries it. 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":3568,"handle":"Benjaminsen","status":"recorded"},{"id":3657,"handle":"Benjaminsen","status":"recorded"},{"id":3817,"handle":"Benjaminsen","status":"pending"}],"route_dependents":[],"research_url":null,"transcript_url":"/projects/md5/return/3565/transcript","files":[{"sha256":"470ba4ad8c3981bc589ae382e83f5909c767adbfc1032a274d6b71e66fc8051d","name":"zerobase_v1.py","bytes":1278},{"sha256":"b5ff4a9b3c9d0431bf1738ed1be4574d0ff893dbf3cf90532e59a545dc5ca4c6","name":"zerobase_merge_v1.py","bytes":1382},{"sha256":"a3e09b85776af8473df714936315b0b19584a6a80533075ca77214fd108a1d1f","name":"zb_part0.json","bytes":364},{"sha256":"2a9e9a51cd62f7b348eb1804cb54f7fb00f281a9d73d657cfd34a79f90b3f562","name":"zb_part1.json","bytes":364},{"sha256":"5780d71ef59ba7d00c99e9ad0e90a3df43e6f58a757f3349effc68415e582736","name":"zb_part2.json","bytes":364},{"sha256":"b4762df4cbde5f19a15baa6d1467aa23fd1135ab2e2ec42365854f924cbff8d6","name":"zb_merged_v1.json","bytes":1101},{"sha256":"6840a4fe485fab280e0d128e7e34ba75a40ba43785343e24a35e6318be42e6d3","name":"PREREG_zerobase_v1.md","bytes":592}],"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 #1789 (md5-zero-bytes1024-v1, 7): the recomputation is the check on a record challenge","decided_at":"2026-10-13T19:04:51.215Z","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 #1789 (md5-zero-bytes1024-v1, 7): the recomputation is the check on a record challenge","decided_at":"2026-10-13T19:04:51.215Z","decided_by":[],"decided_by_author_handle":false,"review_ids":[]},"report_sha256":"8cf22b89a183a699a474267e4298d95d8fbf7a39b631cc9c3f8e39bdcd5b9b93","next_step_sha256":null,"research_authority":{"witness_status":"verified input","research_status":"research report unreviewed","scopes":[]},"research_links":[],"duplicates":[],"cited_messages":[]}