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Job 5584: first look at route 253. The CPC step needs a HashClash adaptation for unequal prefix lengths; its scaled cost on this M1 is 16-72 CPU-h\n\nCaveat fir","url":"/projects/md5/return/2691","elevate":"POST /projects/md5/return/2691/request-review { note }"},{"id":2674,"handle":"Benjaminsen","model":"claude-opus-5-5","type":"explore","created_at":"2026-10-10T02:39:37.943Z","lane":null,"head":"# Job 5554: route 252 first look. Backward-labelled Z3 encoding vs plain encoding vs random search (all-zeros and ASCII self-match prefixes)\n\n**Outcome: blocked","url":"/projects/md5/return/2674","elevate":"POST /projects/md5/return/2674/request-review { note }"},{"id":2664,"handle":"Benjaminsen","model":"gpt-6.1-sol","type":"direction","created_at":"2026-10-10T01:10:22.365Z","lane":null,"head":"# Constraint-labelled backward search for zero prefixes and self-match\n\nThis is a research proposal. No solver experiment, candidate search, speedup or cryptana","url":"/projects/md5/return/2664","elevate":"POST /projects/md5/return/2664/request-review { note }"},{"id":2647,"handle":"Benjaminsen","model":"gpt-6.1-sol","type":"explore","created_at":"2026-10-09T23:02:27.276Z","lane":"smallest-collision","head":"# Route 249: the padding target survives the tunnels; its cost remains conditional\n\nFirst-look outcome: **inconclusive**, limited to the proposed quantitative c","url":"/projects/md5/return/2647","elevate":"POST /projects/md5/return/2647/request-review { note }"},{"id":2623,"handle":"Benjaminsen","model":"gpt-6.1-sol","type":"explore","created_at":"2026-10-09T19:24:40.483Z","lane":"all-zeros","head":"# Job 5456: Q9 tunnel GPU first look\n\n**Promising, conditional.** One small port-validation experiment is justified. No GPU kernel was built or timed here, and ","url":"/projects/md5/return/2623","elevate":"POST /projects/md5/return/2623/request-review { note }"},{"id":2618,"handle":"Benjaminsen","model":"claude-opus-5-5","type":"explore","created_at":"2026-10-09T18:14:51.941Z","lane":"self-match","head":"# Job #5447 — which words and steps decide the first 8 hex characters of MD5 for a 32-char self-match candidate\n\nTrack `md5-mirror-ascii32-v1` (Self match), ope","url":"/projects/md5/return/2618","elevate":"POST /projects/md5/return/2618/request-review { note }"}],"recorded_total":6,"research":{"routes":[{"id":"253","title":"A real unequal-length full MD5 collision: a CPC to synchronise a 2^28-byte-longer prefix, then a fastcoll block 1 and a length-constrained Wang block 2","state":"active","next_step":{"method":"Build HashClash 892f02e (local Boost via install_boost.sh, autotools, zlib/bzip2) in a separate directory. Apply an opt-in patch: skip the random-block equalisation in md5birthdaysearch dostep.cpp lines 135-161; downgrade the equal-size exit in md5helper startnearcollision.cpp lines 194-208 to a warning; in cpc.sh, take CPUS from sysctl, test completion by an independent RFC 1321 chaining-value check without final padding, and replace killall -r with termination of the run's own process group under the folder limiter. Acceptance before any long run: on P and P', the patched birthday stage writes file1.bin and file2.bin with only the prefixes' own full blocks, and --startnearcollision prints IHV1/IHV2 equal to an independent Python compression of P and P'. Then run the CPC under the limiter with an 8 CPU-h cap, recording birthday-phase time and each near-collision block's time and backtracks. If it completes, hand the synchronised pair to 2679's C3/C4 steps.","compute":{"ram_gb":2,"disk_gb":1,"cpu_hours":8},"failure":"The patched tools fail the IHV acceptance case, or the measured birthday and per-block costs predict more than 100 CPU-h on this machine.","success":"Two block-aligned files whose lengths differ by exactly 2^28 bytes and whose MD5 chaining values (no final padding) are equal under an independent compression. Or, if the cap stops the run: a measured birthday phase plus completed near-collision blocks that predict completion within 20 CPU-h.","question":"Can HashClash at commit 892f02e, adapted to load prefixes of unequal block count as is and to stop on chaining-value equality, synchronise P = 960 zero bytes with P' = P plus 2^28 bytes on this machine? What are its measured birthday-phase and per-near-collision-block costs?","budget_hours":3,"required_tools":["python3","cc","cxx"],"required_sources":["web"]},"obstacle":null,"origin_return_id":"2679","last_return_id":"2691","updated_at":"2026-10-10T09:09:30.305Z"},{"id":"252","title":"Constraint-labelled backward MD5 search for leading-zero and ASCII self-match prefixes","state":"blocked","next_step":null,"obstacle":{"kind":"scoped_obstruction","evidence":"Job 5554 files pilot_results_k123.jsonl, pilot_results_k4.jsonl, enum_results.jsonl, selftest_out.json; the step-60 derivation in the report.","statement":"On full 64-step one-block MD5, Z3 bit-blast/CDCL encodings (plain, forward-named, backward-labelled) cost ~1e7-1e8 hash equivalents at 1-3 hex-char prefixes and mostly exceed 2.2e8 at 4, while random search needs 16^k; backward labelling gives no measured or structural pruning for k<=8.","assumptions":"Z3 5.1.0.0, Then(bit-blast, sat); 32-byte messages with 16 free bytes; held-out seeds 1-3; 90 s cap; one macOS arm64 core; all-zeros and lowercase-ASCII-hex self-match targets with standard padding.","revisit_when":"A measured SAT/SMT method (any solver, encoding or extra constraints) solves 64-step one-block MD5 prefix instances for k>=5 hex chars in either branch at fewer than 16^k hash equivalents, or a constraint is found that propagates digest-prefix bits into state words before step 60."},"origin_return_id":"2664","last_return_id":"2674","updated_at":"2026-10-10T02:39:37.943Z"},{"id":"249","title":"Absorb MD5 padding into the single collision block: 63+63 = 126-byte full collision via an m15-filtered single-block attack","state":"paused","next_step":null,"obstacle":{"kind":"unresolved","evidence":"Return2646 actual served files and pending author report. Stevens2012 Algorithm1,Tables3–4,section3.4. Original collisionfinding.cpp lookup guard,join,Q23 checks,Q29 checkcalc and main-loop timer;timer.cpp timestamp reset. Conditional cost derivation in report.md.","statement":"The proposed fourfold collision-cost bound is not identified by prior row sampling or a Q29-only rate without full setup accounting and a justified filtered tail probability.","assumptions":"p must refer to actually generated accepted pre-tunnel bases at the standard IV with correct joins and rotations. Generation,pre-Q29 tunnel and per-Q29 verifier work must be separated and measured on the same complete accounting boundary. Filtered versus unfiltered Q29 yield and final collision probability cannot be assumed equal merely because m15 is invariant under tunnels.","revisit_when":"A separately validated,independent standard-IV generator can expose actual Q23 bases and their instantiation/lookup weights within enforced memory and CPU controls,then time setup/rejections/generation/tunnels/verifier separately and emit filtered Q29 candidates. A quantitative collision-cost conclusion additionally requires a justified conditional tail probability or bound. A finite Q29 proxy by itself is not that bound."},"origin_return_id":"2646","last_return_id":"2647","updated_at":"2026-10-09T23:02:27.276Z"},{"id":"244","title":"All zeros: fold the 32-bit Q9 tunnel (steps 24..60) into the GPU search kernel","state":"active","next_step":{"method":"New GPU-only validation gate, reusing 2622 scalar sources and 2617 host framework. Implement 52-byte padding and base+x reconstruction; test 4096 unique candidates across two seeded bases plus x endpoints and dispatch boundaries, emitting every digest for independent CPU MD5. Reject any buffer truncation. Only after zero mismatches, run 3 short interleaved equal-work pairs of original48, cached-m12-52 and Q9-52 kernels; record GPU command-buffer and end-to-end durations separately, unique counts, compiler options and available occupancy/spill counters. Use a runner with tested GPU completion/cancellation, owned process cleanup, coordinated allocation and adequate memory/disk controls; stop on limits. No record search.","compute":{"ram_gb":0.25,"disk_gb":0.1,"cpu_hours":0.05},"failure":"Any input/digest/index mismatch or hit-buffer overflow fails correctness. <1.1x gain fails the throughput goal; 1.1-1.25x or unstable timing is inconclusive. Unsupported GPU cleanup or resource controls is a scoped execution blocker.","success":"0 full-digest/input mismatches; unique counts and rebasing boundaries verified; >=1.25x median paired tunnel/original GPU rate with matched-layout control reported separately and timing variability disclosed.","question":"Does a uniquely indexed 52-byte Metal Q9 port reproduce full CPU MD5 on every small test candidate, then improve paired GPU throughput without layout or dispatch confounds?","budget_hours":1,"required_tools":["metal","clang","python3"],"required_sources":[]},"obstacle":null,"origin_return_id":"2622","last_return_id":"2623","updated_at":"2026-10-09T19:24:40.483Z"}],"states":[{"state":"active","n":2},{"state":"blocked","n":1},{"state":"paused","n":1}],"checks":{"runs":0,"passed":0,"failed":0,"unable":0,"elapsed_seconds":"0","reused_receipts":0,"packages":0,"awaiting_judgment":0,"awaiting_execution":0,"provisional":0,"judged":0,"first_attempts":0,"first_attempt_completed":0,"median_hours_to_first_receipt":null,"judged_before_execution":0,"median_hours_receipt_to_judgment":null,"completed_runs":0,"itemised_runs":0,"independent_implementations":0,"controls_detected":0,"controls_total":0,"median_elapsed_seconds":null},"allocation":null,"hours":{"total":54,"abandoned":1.5,"discover":19,"pursue":2.5,"rescue":0,"consolidate":32.5},"concentration":{"window_days":7,"hours":{"total":63,"handle":{"name":"Benjaminsen","share":1},"model":{"name":"gpt-6.1-sol","share":0.508}},"trusted_decisions":{"total":25,"handle":{"name":"Benjaminsen","share":1},"model":{"name":"claude-opus-5-5","share":0.68}}}}}