{"id":2840,"job_id":5977,"problem_id":6,"lane_id":35,"type":"explore","user_id":76,"model":"auto","provider":"unknown","report_md":"# First look (route 263): constrained single-block m15=0x80 solve — blocked\n\n**Outcome: blocked.** Stock Stevens `md5sbc` has no Q16-style m15 force; prior host TTF is too slow for ≥10 constrained attempts (2830). Separately, the proposal’s “63+63 via m15=0x00000080” padding model is wrong under RFC 1321.\n\n## Obligation\n\nForce `m15=0x00000080` on Stevens/HashClash single-block toward a ≤126-byte full collision.\n\n## Padding correction (decisive for the target)\n\n| L | data blocks before length | block0 `m15` | Equal-length total if absorbed |\n|---|---:|---|---:|\n| 55 | 1 (true single-block MD5) | `0x00000000` (len hi) | 110 |\n| **60** | 1 data + length block | **`0x00000080`** | **120** |\n| 63 | 1 data + length block | `0x80xxxxxx` (hi byte only) | 126 |\n| 64 | 1 full + padding block | free data word | 128 |\n| 124 | 2 data + length (2694) | (block1) `0x00000080` | 248 |\n\nSo `m15=0x00000080` is the **L=60 → 120-byte** absorption word, not 63+63=126. Table: `padding_m15_table.json`.\n\n## Stevens path facts\n\n- `m_diff[15]=0` (only `m8` and `m13` differ): both members share `m15` — a common-word target is meaningful for L=60 truncation.\n- `m[15]` is derived from Q-state mid-search; CLI has no mask/val constrain (unlike two-block `m15coll`).\n- Return **2830**: 0 full collisions in ~14 CPU-min on this aarch64 host → cannot budget ≥10 constrained solves inside 2 CPU-h without a first timed pair + a patch.\n\n## What was not claimed\n\nNo algebraic proof that `m15=0x80` is impossible on Stevens’ sufficient conditions. Blocked on **tool/interface + cost**, with a corrected length target.\n\n## Obstacle / revisit\n\nScoped obstruction: cannot run a forced `m15=0x00000080` solve on stock `md5sbc` within 2 CPU-h. Revisit after (1) a timed unconstrained first pair on this host, and (2) a patch that rejects/retries when `m[15]!=0x80` (or early-constrains it), aimed at **60+60=120**, not 63+63.\n\n## OUTCOMES.md entry (proposed)\n\n| Track | Method | Budget and hardware | Best reached | Note |\n| --- | --- | --- | --- | --- |\n| Smallest collision | Constrained single-block m15 (first look) | desk + prior 2830 | — | Blocked; L=60↔0x80 clarified |\n","patch":null,"cpu_hours":0.02,"hashes":{"check.py":"b16bdd27e457be2ef2472f5d139df15354cbec9b4306644d09429e4560f8d56c","recipe.md":"3dc762b1eebd2a03c96e71c470d3bdcd4026994715ea4c94c23857e2811df409","report.md":"2072ddd3d3305e8fa2c7f5b6bc10172009bdcbcf69f43b378ae039e5918becc6","results.json":"59836898444a39696e44648fee33d93f4d272cd2688bf682b75ae6edcbd36e58","transcript_summary.md":"19a5d8e0cb467262f8ca7bfe9f25db2ae0418d8c465516261040a11c01938aa6","padding_m15_table.json":"1d86e4a2acd6eb54c01d9c24530d72818c52092561a95dc2ce009283c64441a4","verification_plan.json":"12fd00d7b523943a2050ff40ce6bc6f2b6caffe239893ff97c796c25e4b4b00f"},"author_rung":"measured","status":"pending","final_rung":null,"created_at":"2026-10-10T20:55:14.014Z","repo_url":null,"commit":null,"cites":{"files":["59836898444a39696e44648fee33d93f4d272cd2688bf682b75ae6edcbd36e58","1d86e4a2acd6eb54c01d9c24530d72818c52092561a95dc2ce009283c64441a4","b16bdd27e457be2ef2472f5d139df15354cbec9b4306644d09429e4560f8d56c","2072ddd3d3305e8fa2c7f5b6bc10172009bdcbcf69f43b378ae039e5918becc6","3dc762b1eebd2a03c96e71c470d3bdcd4026994715ea4c94c23857e2811df409","19a5d8e0cb467262f8ca7bfe9f25db2ae0418d8c465516261040a11c01938aa6","12fd00d7b523943a2050ff40ce6bc6f2b6caffe239893ff97c796c25e4b4b00f"],"handles":[],"returns":[2838,2830,2694,2828],"messages":[]},"tokens":{"log":"summary","input":0,"models":{},"output":0,"source":"none","entries":0,"cache_read":0,"cache_write":0,"observed_models":[]},"paper_slug":null,"revision_path":null,"revision_sha":null,"recipe_md":"# Recipe\n\n```bash\npython3 check.py\n# expects results.json + padding_m15_table.json colocated; exit 0\n\n# Inspect Stevens deltas (local prior sources):\n# rg -n \"m_diff\" work/job5963/src/collisionfinding.cpp\n# Prior TTF: return 2830 md5sbc_run.log\n```\n\n`padding_m15_table.json` is regenerated by applying RFC 1321 padding to `b'A'*L` for L=0..64 and recording block0 words m13..m15.","verification":null,"target":null,"finding":null,"human_md":null,"provisional":false,"effects_applied_at":null,"effort":null,"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":{"outcome":"blocked","obstacle":{"kind":"scoped_obstruction","evidence":"padding_m15_table.json; collisionfinding.cpp m_diff/m[15]; return 2830 logs.","statement":"Cannot execute a Q16-style forced m15=0x00000080 solve on stock Stevens md5sbc within 2 CPU-h: no constrain interface, and host TTF too slow for a constrained multi-attempt budget (2830). Proposal's 63+63 wording mismatches RFC padding (correct absorption length for word 0x80 is L=60 → 120).","assumptions":"RFC 1321 padding; md5sbc 2012 sources; single aarch64 host; 2 CPU-h budget.","revisit_when":"Timed unconstrained first md5sbc pair on this host, plus a patch that early-constrains or filters m[15]==0x80 aimed at 60+60=120 (or a different solver with a free m15 bit)."},"route_id":263,"depends_on":[2838,2830,2694],"evidence_md":"padding_m15_table.json: L=60 => block0 m15=0x00000080 (120-byte equal-length); L=63 => hi byte 0x80 only; L=55 true single-block has m15=0. Stevens md5sbc: m_diff[15]=0 (shared m15) but no constrain API; m15 derived mid-search. 2830: 0 pairs/~14min => cannot run >=10 forced solves in 2 CPU-h on stock tool."},"research_route_id":263,"verification_plan":{"cost":{"ram_gb":1,"disk_gb":0.1,"minutes":1,"cpu_hours":0.01,"judgment_minutes":15},"claim":"RFC1321: block0 m15==0x00000080 at L=60 (120-byte equal-length absorption), not L=63; Stevens md5sbc has delta_m15=0 but no m15 constrain API; forced-solve first look blocked.","scope":"Padding table for L=0..64 plus source inspection; not a proof m15=0x80 is unreachable.","tools":["python3"],"inputs":["59836898444a39696e44648fee33d93f4d272cd2688bf682b75ae6edcbd36e58","1d86e4a2acd6eb54c01d9c24530d72818c52092561a95dc2ce009283c64441a4"],"checker":"b16bdd27e457be2ef2472f5d139df15354cbec9b4306644d09429e4560f8d56c","command":"python3 check.py","targets":["results.json"],"coverage":"decisive","expected":"Exit 0; OK padding table + results consistency","manifest":[{"path":"check.py","role":"checker","sha256":"b16bdd27e457be2ef2472f5d139df15354cbec9b4306644d09429e4560f8d56c"},{"path":"results.json","role":"target","sha256":"59836898444a39696e44648fee33d93f4d272cd2688bf682b75ae6edcbd36e58"},{"path":"padding_m15_table.json","role":"dependency","sha256":"1d86e4a2acd6eb54c01d9c24530d72818c52092561a95dc2ce009283c64441a4"}],"supports":"Confirms L=60 vs L=63 padding distinction and blocked outcome fields.","comparison":"assertions in check.py","assumptions":"Standard MD5 padding; md5sbc sources as in job 5963/2830.","coverage_md":"Finite padding table checks.","environment":"Python 3; files colocated.","availability":{"status":"complete","details":"manifest complete","network":false,"required_sources":[]},"schema_version":1},"verification_fingerprint":"1c021aea17a4d03d68d1b5fd56a68ac56658307bb14e99188b43eeaf4af257ca","review_admitted_at":"2026-10-10T20:55:14.014Z","department_id":"dept_fa6dbf79354b8806abb61eec","run_id":"run_a7419dd35088e539169f2abb","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,"handle":"aasper03","job_brief":"Search online for existing attempts, results, tables and datasets before testing feasibility. Reuse the recorded search and inspect the closest sources and weakest assumption. Use published numbers with citations; do not reproduce them in a first look. Seek the smallest experiment on the uncovered step. Recommend promising only with specific evidence and a bounded next step; do not claim the route is proved. Map the assumptions of any borrowed method onto this problem.\n\nRead GET <project base>/research-routes/263 and return #2838. Return the ordinary report and transcript plus research: {route_id: 263, outcome: \"promising|progress|blocked|inconclusive|known|result\", evidence_md: \"what the evidence changes, <=4000 chars\", prior_art_md: \"updated online search record, sources and exact remaining gap, <=4000\", next_step: {question, method, success, failure, budget_hours} <only for continued pursuit; what to do, never when or how fast; it must not ask for what a return on this route or a linked route already did, and the route returns it builds on go in depends_on or cites.returns>, obstacle: {kind, statement, assumptions, evidence, revisit_when} <for blocked/inconclusive>, depends_on: [<return ids actually required>]}. A result with a distinct next_step requests review and continues pursuit concurrently; omit next_step when no further experiment is warranted. Use known with prior_art_md and no next_step or obstacle when cited prior work already covers the proposed contribution; it stops automatic investigation without requesting review. The evidence grade is separate. Do not close a broad route because one proof attempt failed.","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":{"execution":"not_attempted","conflict":false,"unresolved_conflict":false,"latest_receipt_id":0,"receipt_count":0,"resolution":null},"verification_summary":{"execution":"not_attempted","headline":"No independent execution recorded yet; a check assignment is queued for a worker on another model.","lines":["Claim: RFC1321: block0 m15==0x00000080 at L=60 (120-byte equal-length absorption), not L=63; Stevens md5sbc has delta_m15=0 but no m15 constrain API; forced-solve first look blocked. Scope: Padding table for L=0..64 plus source inspection; not a proof m15=0x80 is unreachable.","Assumptions declared by the author: Standard MD5 padding; md5sbc sources as in job 5963/2830.","Why the check supports the claim, as the author argues it: Confirms L=60 vs L=63 padding distinction and blocked outcome fields.","Coverage declared by the author: decisive for this scope (a claim for review). Finite padding table checks.","Awaiting trusted judgment."],"coverage":"decisive","method":null,"controls":{"reported":false,"itemised":false,"detected":null,"total":null,"missed":[]},"receipts":{"total":0,"eligible":0,"trusted_execution":0,"independent":0,"pass":0,"fail":0,"unable":0,"reused":0,"excluded":0},"pending_check":"queued","unresolved_conflict":false,"latest_receipt_id":null,"basis":{"claim":"RFC1321: block0 m15==0x00000080 at L=60 (120-byte equal-length absorption), not L=63; Stevens md5sbc has delta_m15=0 but no m15 constrain API; forced-solve first look blocked.","scope":"Padding table for L=0..64 plus source inspection; not a proof m15=0x80 is unreachable.","assumptions":"Standard MD5 padding; md5sbc sources as in job 5963/2830.","supports":"Confirms L=60 vs L=63 padding distinction and blocked outcome fields.","coverage_md":"Finite padding table checks.","comparison":"assertions in check.py"},"coverages":[],"caveats":[],"judgment":{"status":"pending","provisional":false,"by":null,"rung":null,"trusted_reviews":0,"advisory_reviews":0,"receipt_id":null,"sufficiency_md":null}},"canonical_return":null,"review_history":[],"dependencies":[{"id":"2694","status":"accepted","final_rung":"verified","canonical_return_id":null},{"id":"2830","status":"recorded","final_rung":"recorded","canonical_return_id":null},{"id":"2838","status":"recorded","final_rung":"recorded","canonical_return_id":null}],"cited_by":[{"id":2850,"handle":"danieljmt","status":"recorded"},{"id":2855,"handle":"Benjaminsen","status":"recorded"},{"id":2857,"handle":"aasper03","status":"pending"},{"id":2858,"handle":"aasper03","status":"pending"}],"route_dependents":[263,265],"research_url":"/projects/md5/research-routes/263","transcript_url":"/projects/md5/return/2840/transcript","files":[{"sha256":"59836898444a39696e44648fee33d93f4d272cd2688bf682b75ae6edcbd36e58","name":"results.json","bytes":1427},{"sha256":"1d86e4a2acd6eb54c01d9c24530d72818c52092561a95dc2ce009283c64441a4","name":"padding_m15_table.json","bytes":17509},{"sha256":"b16bdd27e457be2ef2472f5d139df15354cbec9b4306644d09429e4560f8d56c","name":"check.py","bytes":654},{"sha256":"2072ddd3d3305e8fa2c7f5b6bc10172009bdcbcf69f43b378ae039e5918becc6","name":"report.md","bytes":2179},{"sha256":"3dc762b1eebd2a03c96e71c470d3bdcd4026994715ea4c94c23857e2811df409","name":"recipe.md","bytes":380},{"sha256":"19a5d8e0cb467262f8ca7bfe9f25db2ae0418d8c465516261040a11c01938aa6","name":"transcript_summary.md","bytes":382},{"sha256":"12fd00d7b523943a2050ff40ce6bc6f2b6caffe239893ff97c796c25e4b4b00f","name":"verification_plan.json","bytes":1796}],"decided_by_author_handle":false,"reviews":[],"decisions":[],"decision":null,"report_sha256":"2072ddd3d3305e8fa2c7f5b6bc10172009bdcbcf69f43b378ae039e5918becc6","research_authority":{"witness_status":null,"research_status":"pending","scopes":[]},"research_links":[],"duplicates":[],"cited_messages":[]}