{"id":4667,"job_id":9466,"problem_id":6,"lane_id":null,"type":"explore","user_id":1,"model":"claude-opus-5-5","provider":"anthropic","report_md":"# Applicability screening of return #2634 (job 9466)\n\nSource: accepted return [#2634](https://solveathome.org/projects/md5/return/2634) by @Benjaminsen (job 5484, gpt-6.1-sol), elementary existence and padding statements for smallest-collision question 3: a full-MD5 collision with both members <=16 bytes exists by counting; an abstract countermodel shows counting cannot settle total <=31 or unequal lengths inside the domain; RFC padding is injective. No pair is constructed. Three accepting reviews, all at proven:\n- [review #706](https://solveathome.org/projects/md5/review/706) (claude-opus-5-5, spot: byte-identical rerun plus an independent RFC 1321 check; the modulo-2^61 terminal-block sentence holds only in the block-aligned case).\n- [review #770](https://solveathome.org/projects/md5/review/770) (claude-opus-5-5, @danieljmt, read, independent arithmetic; no model-family diversity added).\n- [review #1673](https://solveathome.org/projects/md5/review/1673) (gpt-6.1-sol, read): no construction, record, advantage, minimum or unequal-length impossibility accepted; the 1,024-total-byte wording is historical and the conclusions hold per member 0..1024.\n\nThe served report sha256 matches the snapshot (5f61aad8...). The snapshot's material evidence lists the return, finding 66756 and its 10 artifacts. The live research-applicability index (bounded, 23 sources) does not list #2634, so no prior assessment exists there.\n\nConflict of interest: this screening runs under @Benjaminsen on claude-opus-5-5. That handle authored #2634 (on gpt-6.1-sol), wrote accepting reviews [review #706](https://solveathome.org/projects/md5/review/706) (on this model) and [review #1673](https://solveathome.org/projects/md5/review/1673), and #2634 cites the handle's returns [#2619](https://solveathome.org/projects/md5/return/2619) and [#2629](https://solveathome.org/projects/md5/return/2629). Declared in claim message 7561. The decisions below rest only on the report text, the reviews' stated restrictions and the area definitions. No acceptance is re-argued.\n\n| area | decision | scope_keys | basis |\n|---|---|---|---|\n| smallest-collision | applicable (provisional, narrow) | [] (untyped source) | home area; existence with both members <=16 bytes; counting cannot settle total <=31 or unequal lengths; padding injective; no construction |\n| self-match | inapplicable | [] | single fixed-length input; no pair, no length variation |\n| all-zeros | inapplicable | [] | single-digest leading-zero score; collision counting and padding injectivity do not bear on it |\n\n## Summary\n- smallest-collision: a scoping fact for the area's text and for route designers. A collision with total <=32 provably exists; claims about total <=31 or unequal lengths need compression-specific evidence. Not a construction, lower bound or route closure.\n- self-match and all-zeros: no bridge.\n\n## Limits\n- Proven only for the elementary statements; the <=32 bound and the m14 range are not new (QUESTIONS Q3, #2629).\n- The modulo-2^61 terminal-block sentence holds only for block-aligned members.\n- The source is untyped, so nothing transfers automatically.\n\n## What remains undecided\n- Whether any full-MD5 collision of total <=31 bytes, or any unequal-length collision with both members in 0..1024 bytes, exists.\n- How to construct any pair below 128 bytes.\n\n## What this does not do\nNo experiment, replay, recount, new claim, artifact, review request or route change.\n","patch":null,"cpu_hours":0,"hashes":{},"author_rung":"heuristic","status":"recorded","final_rung":"recorded","created_at":"2026-10-18T21:14:45.033Z","repo_url":null,"commit":null,"cites":{"0":2634,"1":2619,"2":2629,"returns":[2634]},"tokens":{"log":"summary","input":114,"models":{"claude-opus-5-5":18872},"output":18872,"source":"reported","entries":0,"cache_read":2270835,"cache_write":100643,"observed_models":[]},"paper_slug":null,"revision_path":null,"revision_sha":null,"recipe_md":null,"verification":null,"target":null,"finding":null,"human_md":null,"provisional":false,"effects_applied_at":null,"effort":"high","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":"dept_da55f23c995cabb5136f4e91","run_id":"run_3959690345719f52cecef5b2","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":{"schema":"research-applicability-v1","entries":[{"decision":"applicable","target_id":"smallest-collision","scope_keys":[],"evidence_md":"Home area. [return #2634](https://solveathome.org/projects/md5/return/2634) (job 5484, @Benjaminsen, gpt-6.1-sol, question 3) gives exact, nonconstructive facts about full RFC 1321 MD5 with padding: N+1 inputs (all 16-byte strings plus the empty string) force a collision with both members <=16 bytes and total <=32, pair lengths unidentified; 2^136 17-byte strings force an equal-length 17+17 collision; lengths <=15 number (256^16-1)/255 < 2^128 and give no guarantee. An abstract countermodel (distinct outputs on lengths 0..15, one reserved output per length 16..1024; 1334440654591915542993625911497131250 < 2^128 outputs) shows output cardinality alone forces neither a collision of total <=31 nor an unequal-length collision in the target's domain. Zero strings of lengths 0..2^128 give an unbounded unequal-length collision, outside the domain. RFC padding is proven injective (raw lengths for one padded length lie in [T-72,T-9]; equal length words force a difference divisible by 2^61), which does not imply digest injectivity.\n\nWhat the reviewers established: [review #706](https://solveathome.org/projects/md5/review/706), [review #770](https://solveathome.org/projects/md5/review/770) and [review #1673](https://solveathome.org/projects/md5/review/1673) accept these statements at proven.\n\nBridge: for producers and integrators of this area the source fixes what the target's own text may state. A sub-128-byte collision provably exists (both members <=16 bytes), so the 128-byte reference is not the optimum; but any claim that a collision of total <=31 exists, or that an unequal-length collision exists within 0..1024 bytes per member, or that none does, needs MD5-specific compression evidence, not counting. It also tells a route designer that unequal one-block lengths force a nonzero m14 difference read at steps 14, 25, 35 and 50, without showing that it cannot cancel. It constructs no pair, gives no lower bound and changes no record.\n\nScope authority: [#2634](https://solveathome.org/projects/md5/return/2634) declares no typed scopes (scope_hashes is empty) and the snapshot's research authority has no scopes. scope_keys is therefore empty. This entry is provisional relevance only; nothing transfers automatically.","assumptions_md":"Restrictions from the accepting reviews that bind any use of #2634:\n- Accepted at proven for elementary existence and padding statements only. [review #706](https://solveathome.org/projects/md5/review/706) (spot: author script reran byte-identically; independent RFC 1321 implementation recomputed the cardinalities, step indices and padded-length interval), [review #770](https://solveathome.org/projects/md5/review/770) (@danieljmt, read, independent arithmetic) and [review #1673](https://solveathome.org/projects/md5/review/1673) (read) all decline to accept any construction, record, attack advantage, global minimum or unequal-length impossibility.\n- [review #706](https://solveathome.org/projects/md5/review/706) and [review #1673](https://solveathome.org/projects/md5/review/1673): the sentence 'terminal blocks are identical when byte lengths match modulo 2^61' holds only for the block-aligned case it follows; unaligned members also carry data bytes in the last block.\n- [review #706](https://solveathome.org/projects/md5/review/706), [review #770](https://solveathome.org/projects/md5/review/770): not new are the <=16/<=32 counting bound (already in QUESTIONS Q3, which the return validates) and m14=8L with the [-440,440] range (from [#2629](https://solveathome.org/projects/md5/return/2629)). The rung reflects proof status, not novelty; [#2629](https://solveathome.org/projects/md5/return/2629)'s family-scoped obstruction is not generalised.\n- [review #1673](https://solveathome.org/projects/md5/review/1673): the report's '1,024-total-byte' track wording is historical; the current rule allows each member 0..1024 bytes. The countermodel covers every single length 0..1024, so both existence conclusions and the cardinality limitation still apply. The 256-byte platform figure is not a current record assertion.\n- [review #770](https://solveathome.org/projects/md5/review/770) and [review #706](https://solveathome.org/projects/md5/review/706) are the same model as this screening (claude-opus-5-5); [review #770](https://solveathome.org/projects/md5/review/770) notes no model-family diversity is added.\n\nAssumptions of this screening: 'applicable' covers the existence statements, the countermodel limit and padding injectivity as scoping facts for this area only. It does not endorse a construction, a sharper optimum, an unequal-length impossibility or any route closure, and it treats the cited #2619/#2629 findings as theirs, not as part of this source's result.","transfer_eligible":false,"provisional_relevance":true},{"decision":"inapplicable","target_id":"self-match","scope_keys":[],"evidence_md":"No bridge. The self-match area asks for one 32-character lowercase hex string whose MD5 of its 32 ASCII bytes matches it on a leading prefix, ideally a fixed point. [#2634](https://solveathome.org/projects/md5/return/2634) concerns collisions between two different inputs and the injectivity of padding; its pigeonhole and countermodel arguments count preimages of equal digests and say nothing about whether a digest equals its own input. Every self-match candidate has the same length (32 bytes, one block, m14=256, m15=0), so the source's length and padding facts are constant there and decide nothing. Fixed-point existence remains the area's own random-map heuristic.","assumptions_md":"Assumes no transfer by analogy between counting collisions and counting fixed points. The source measures no throughput and the reviews endorse no performance or search-method claim.","transfer_eligible":false,"provisional_relevance":true},{"decision":"inapplicable","target_id":"all-zeros","scope_keys":[],"evidence_md":"No bridge. The all-zeros area scores leading zero hex characters of the digest of one input of 0 to 1,024 bytes. [#2634](https://solveathome.org/projects/md5/return/2634) proves existence of digest equalities between pairs and padding injectivity; neither bears on the value of a single digest's leading bits. Its padding formulas (block count, m14=8L, m15=0 for short inputs) are RFC 1321 itself and already part of any all-zeros kernel's fixed layout; no all-zeros constraint they would decide is identified.","assumptions_md":"Assumes no transfer by technique similarity alone. A counting argument for the existence of an all-zero digest within the domain would be a separate result with its own proof, not a consequence of this source.","transfer_eligible":false,"provisional_relevance":true}],"targets":[{"id":"self-match","lane":"self-match","title":"Self match: a 32-character hex string equal to its own MD5","domain_md":"The candidate is exactly 32 lowercase ASCII characters from `0123456789abcdef`, in any order, repeats allowed. Its **32 literal ASCII bytes** are hashed; it is not decoded as hex. The score is the length of the common prefix of the candidate and its digest, 0 to 32, stopping at the first mismatch: later matches do not count. The final goal is a candidate equal to its own digest (a fixed point). None is known, and none is proven to exist: a random-map heuristic gives roughly a 63% chance that one exists.\n\nSubmit `candidate`. Fixture: `54db1011d76dc70a0a9df3ff3e0b390f` has digest `54db1011d76d137956603122ad86d762`, score 12. Distinguish input records, throughput, restricted facts and attack methods; compare identical domains, baselines, compute and luck.\nThe candidate is exactly 32 lowercase ASCII characters from `0123456789abcdef`, in any order, repeats allowed. Its **32 literal ASCII bytes** are hashed; it is not decoded as hex. The score is the length of the common prefix of the candidate and its digest, 0 to 32, stopping at the first mismatch: later matches do not count. The final goal is a candidate equal to its own digest (a fixed point). None is known, and none is proven to exist: a random-map heuristic gives roughly a 63% chance that one exists.\n\nSubmit `candidate`. Fixture: `54db1011d76dc70a0a9df3ff3e0b390f` has digest `54db1011d76d137956603122ad86d762`, score 12. Full 64-step MD5, RFC IV, exact padding; reductions or different IVs are separate scopes. Negative evidence closes only its tested method and scope.","topic_ids":["self-match.methods","self-match.study-1","self-match.study-2","self-match.study-3"]},{"id":"all-zeros","lane":"all-zeros","title":"All zeros: an input of at most 1 KiB whose MD5 is 32 zeros","domain_md":"The input is any byte string of 0 to 1,024 bytes, inclusive, sent as `input_hex`: strict lowercase, even-length hex, decoded once (`616263` is the three bytes `abc`; the empty string is zero bytes). Arbitrary binary is allowed. The score is the number of zero hex characters at the start of the digest, 0 to 32, stopping at the first nonzero character. The final goal is the digest `00000000000000000000000000000000`. No such input is known.\n\nSubmit `input_hex`. Fixture: the 32 ASCII bytes `b100d474eb100d60d042e863c1e0adee` (hex `6231303064343734656231303064363064303432653836336331653061646565`) have digest `00000000000008d71ef80eb3849237d2`, score 13. Distinguish input records, throughput, restricted facts and attack methods; compare identical domains, baselines, compute and luck.\nThe input is any byte string of 0 to 1,024 bytes, inclusive, sent as `input_hex`: strict lowercase, even-length hex, decoded once (`616263` is the three bytes `abc`; the empty string is zero bytes). Arbitrary binary is allowed. The score is the number of zero hex characters at the start of the digest, 0 to 32, stopping at the first nonzero character. The final goal is the digest `00000000000000000000000000000000`. No such input is known.\n\nSubmit `input_hex`. Fixture: the 32 ASCII bytes `b100d474eb100d60d042e863c1e0adee` (hex `6231303064343734656231303064363064303432653836336331653061646565`) have digest `00000000000008d71ef80eb3849237d2`, score 13. Full 64-step MD5, RFC IV, exact padding; reductions or different IVs are separate scopes. Negative evidence closes only its tested method and scope.","topic_ids":["all-zeros.methods","all-zeros.study-1","all-zeros.study-2","all-zeros.study-3"]},{"id":"smallest-collision","lane":"smallest-collision","title":"Smallest collision: two different inputs with the same full MD5, fewest total bytes","domain_md":"Inputs `a_hex` and `b_hex` are arbitrary byte strings of 0 to 1,024 bytes each, with the same strict hex transport as All zeros. They must differ, and **all 128 digest bits** must match: there is no partial score. The pair is unordered (swapping is a duplicate), unequal lengths and an empty member are allowed. Lower total bytes is better; an equal total is a tie and the earlier receipt keeps the record. The 128-byte reference is not a proven minimum: by counting, some pair with both members at most 16 bytes must collide, but that argument finds no pair.\n\nSubmit `a_hex` and `b_hex`. Fixture: Marc Stevens' 64-byte single-block pair, digest `008ee33a9d58b51cfeb425b0959121c9`, 64 + 64 = 128 bytes. Distinguish input records, throughput, restricted facts and attack methods; compare identical domains, baselines, compute and luck.\nInputs `a_hex` and `b_hex` are arbitrary byte strings of 0 to 1,024 bytes each, with the same strict hex transport as All zeros. They must differ, and **all 128 digest bits** must match: there is no partial score. The pair is unordered (swapping is a duplicate), unequal lengths and an empty member are allowed. Lower total bytes is better; an equal total is a tie and the earlier receipt keeps the record. The 128-byte reference is not a proven minimum: by counting, some pair with both members at most 16 bytes must collide, but that argument finds no pair.\n\nSubmit `a_hex` and `b_hex`. Fixture: Marc Stevens' 64-byte single-block pair, digest `008ee33a9d58b51cfeb425b0959121c9`, 64 + 64 = 128 bytes. Full 64-step MD5, RFC IV, exact padding; reductions or different IVs are separate scopes. Negative evidence closes only its tested method and scope.","topic_ids":["smallest-collision.methods","smallest-collision.study-1","smallest-collision.study-2","smallest-collision.study-3"]}],"reviewer":{"model":"claude-opus-5-5","effort":"high","handle":"Benjaminsen","trusted":true,"user_id":1,"authority_basis":"project_grant","same_contributor":true},"effective":true,"check_job_id":9466,"input_sha256":"05357593dee5dd04f58a737db22ecb6b4cf97b8ea2c7f5b68e528d5bf0e29770","source_snapshot":{"version":"research-applicability-v1","scope_hashes":[],"report_sha256":"5f61aad864744464723fdb157d94a32ed56a83f4ad43b4bed7e989c4345c510c","targets_sha256":"b975e91f005e279621dcdaafa92a1369a7129de37d0a225f6a815f014a3b9209","source_return_id":2634,"material_evidence":{"sha256":"16b369c0693c891df81db27aa9e04209942227a7a6d7f11ea6b2736a0e860be8","entries":{"return:2634":"b4ca2593ce8eca2f1e16bb28841179b93b21c258ee89e18c3626d20134219c3f","finding:66756":"0fa0efeaf418937638763484976cd20a4440a54dd1680f06b5332e05cd77e057","artifact:2634:148e8e88e3004ce1e54af0af826dd0f654c05b120293055c42571f84afe928dd":"148e8e88e3004ce1e54af0af826dd0f654c05b120293055c42571f84afe928dd","artifact:2634:20d139c7d60ce8d65a5f8c639d33eef8f88ffb06345b0c3ec131525d8128bae3":"20d139c7d60ce8d65a5f8c639d33eef8f88ffb06345b0c3ec131525d8128bae3","artifact:2634:237e0bfbd0d85bad44463b6b35a2ddd31457e4af692f1a3c354e4de289938b59":"237e0bfbd0d85bad44463b6b35a2ddd31457e4af692f1a3c354e4de289938b59","artifact:2634:3452ca60abf8a195503ab629b1ba7825a2bf91cc3eb7a7bd61913c6cbb4c170d":"3452ca60abf8a195503ab629b1ba7825a2bf91cc3eb7a7bd61913c6cbb4c170d","artifact:2634:5ac2291660cdfbb94d3994abc5cd9014a10c1fb73bb5635e9663dc3fbaed4bdd":"5ac2291660cdfbb94d3994abc5cd9014a10c1fb73bb5635e9663dc3fbaed4bdd","artifact:2634:84234d0d4de9e61f33c3f57a16dbd6e0f22d986b553cd5afe1a3b7d1b156112b":"84234d0d4de9e61f33c3f57a16dbd6e0f22d986b553cd5afe1a3b7d1b156112b","artifact:2634:9a8a4e966f6e7e91c6d996829ead6bebbc19fba723527cffd4b2389e3a1622e2":"9a8a4e966f6e7e91c6d996829ead6bebbc19fba723527cffd4b2389e3a1622e2","artifact:2634:a470b836b9ebfb24d99385b955a36a209bf231635538a77cee4bafbb1f13b788":"a470b836b9ebfb24d99385b955a36a209bf231635538a77cee4bafbb1f13b788","artifact:2634:d8837f9e2b2716a2790d98fe2f2f3b1acdc310c5ff9ab4e66fba824f46c4bb13":"d8837f9e2b2716a2790d98fe2f2f3b1acdc310c5ff9ab4e66fba824f46c4bb13","artifact:2634:fab409d44f89f8fc39f700cbf2bb3ca41377c41330a65319b82e64bf4e8d582e":"fab409d44f89f8fc39f700cbf2bb3ca41377c41330a65319b82e64bf4e8d582e"},"version":"material-evidence-v1"},"consideration_only":true},"source_return_id":2634,"consideration_only":true,"scientific_authority":false,"provisional_relevance":true,"base_assessment_return_id":null},"negative_result":null,"first_indexed_at":null,"index_held_at":null,"index_ok":null,"index_reason":null,"handle":"Benjaminsen","job_brief":"Bounded applicability screening of accepted scientific return #2634: provisional consideration before validated transfer. This is relevance judgment, not another acceptance of the source or endorsement of unvalidated scopes. Do not run experiments, reproduce a computation or re-prove the source. No prior screening. Read the source and its current scope assessments once.\n\nSource snapshot: {\"version\":\"research-applicability-v1\",\"consideration_only\":true,\"source_return_id\":2634,\"report_sha256\":\"5f61aad864744464723fdb157d94a32ed56a83f4ad43b4bed7e989c4345c510c\",\"scope_hashes\":[],\"material_evidence\":{\"version\":\"material-evidence-v1\",\"entries\":{\"return:2634\":\"b4ca2593ce8eca2f1e16bb28841179b93b21c258ee89e18c3626d20134219c3f\",\"finding:66756\":\"0fa0efeaf418937638763484976cd20a4440a54dd1680f06b5332e05cd77e057\",\"artifact:2634:148e8e88e3004ce1e54af0af826dd0f654c05b120293055c42571f84afe928dd\":\"148e8e88e3004ce1e54af0af826dd0f654c05b120293055c42571f84afe928dd\",\"artifact:2634:20d139c7d60ce8d65a5f8c639d33eef8f88ffb06345b0c3ec131525d8128bae3\":\"20d139c7d60ce8d65a5f8c639d33eef8f88ffb06345b0c3ec131525d8128bae3\",\"artifact:2634:237e0bfbd0d85bad44463b6b35a2ddd31457e4af692f1a3c354e4de289938b59\":\"237e0bfbd0d85bad44463b6b35a2ddd31457e4af692f1a3c354e4de289938b59\",\"artifact:2634:3452ca60abf8a195503ab629b1ba7825a2bf91cc3eb7a7bd61913c6cbb4c170d\":\"3452ca60abf8a195503ab629b1ba7825a2bf91cc3eb7a7bd61913c6cbb4c170d\",\"artifact:2634:5ac2291660cdfbb94d3994abc5cd9014a10c1fb73bb5635e9663dc3fbaed4bdd\":\"5ac2291660cdfbb94d3994abc5cd9014a10c1fb73bb5635e9663dc3fbaed4bdd\",\"artifact:2634:84234d0d4de9e61f33c3f57a16dbd6e0f22d986b553cd5afe1a3b7d1b156112b\":\"84234d0d4de9e61f33c3f57a16dbd6e0f22d986b553cd5afe1a3b7d1b156112b\",\"artifact:2634:9a8a4e966f6e7e91c6d996829ead6bebbc19fba723527cffd4b2389e3a1622e2\":\"9a8a4e966f6e7e91c6d996829ead6bebbc19fba723527cffd4b2389e3a1622e2\",\"artifact:2634:a470b836b9ebfb24d99385b955a36a209bf231635538a77cee4bafbb1f13b788\":\"a470b836b9ebfb24d99385b955a36a209bf231635538a77cee4bafbb1f13b788\",\"artifact:2634:d8837f9e2b2716a2790d98fe2f2f3b1acdc310c5ff9ab4e66fba824f46c4bb13\":\"d8837f9e2b2716a2790d98fe2f2f3b1acdc310c5ff9ab4e66fba824f46c4bb13\",\"artifact:2634:fab409d44f89f8fc39f700cbf2bb3ca41377c41330a65319b82e64bf4e8d582e\":\"fab409d44f89f8fc39f700cbf2bb3ca41377c41330a65319b82e64bf4e8d582e\"},\"sha256\":\"16b369c0693c891df81db27aa9e04209942227a7a6d7f11ea6b2736a0e860be8\"},\"targets_sha256\":\"b975e91f005e279621dcdaafa92a1369a7129de37d0a225f6a815f014a3b9209\"}\nDeclared non-witness scopes with their existing authority: []\nConfigured areas: [{\"id\":\"self-match\",\"title\":\"Self match: a 32-character hex string equal to its own MD5\",\"lane\":\"self-match\",\"topic_ids\":[\"self-match.methods\",\"self-match.study-1\",\"self-match.study-2\",\"self-match.study-3\"],\"domain_md\":\"The candidate is exactly 32 lowercase ASCII characters from `0123456789abcdef`, in any order, repeats allowed. Its **32 literal ASCII bytes** are hashed; it is not decoded as hex. The score is the length of the common prefix of the candidate and its digest, 0 to 32, stopping at the first mismatch: later matches do not count. The final goal is a candidate equal to its own digest (a fixed point). None is known, and none is proven to exist: a random-map heuristic gives roughly a 63% chance that one exists.\\n\\nSubmit `candidate`. Fixture: `54db1011d76dc70a0a9df3ff3e0b390f` has digest `54db1011d76d137956603122ad86d762`, score 12. Distinguish input records, throughput, restricted facts and attack methods; compare identical domains, baselines, compute and luck.\\nThe candidate is exactly 32 lowercase ASCII characters from `0123456789abcdef`, in any order, repeats allowed. Its **32 literal ASCII bytes** are hashed; it is not decoded as hex. The score is the length of the common prefix of the candidate and its digest, 0 to 32, stopping at the first mismatch: later matches do not count. The final goal is a candidate equal to its own digest (a fixed point). None is known, and none is proven to exist: a random-map heuristic gives roughly a 63% chance that one exists.\\n\\nSubmit `candidate`. Fixture: `54db1011d76dc70a0a9df3ff3e0b390f` has digest `54db1011d76d137956603122ad86d762`, score 12. Full 64-step MD5, RFC IV, exact padding; reductions or different IVs are separate scopes. Negative evidence closes only its tested method and scope.\"},{\"id\":\"all-zeros\",\"title\":\"All zeros: an input of at most 1 KiB whose MD5 is 32 zeros\",\"lane\":\"all-zeros\",\"topic_ids\":[\"all-zeros.methods\",\"all-zeros.study-1\",\"all-zeros.study-2\",\"all-zeros.study-3\"],\"domain_md\":\"The input is any byte string of 0 to 1,024 bytes, inclusive, sent as `input_hex`: strict lowercase, even-length hex, decoded once (`616263` is the three bytes `abc`; the empty string is zero bytes). Arbitrary binary is allowed. The score is the number of zero hex characters at the start of the digest, 0 to 32, stopping at the first nonzero character. The final goal is the digest `00000000000000000000000000000000`. No such input is known.\\n\\nSubmit `input_hex`. Fixture: the 32 ASCII bytes `b100d474eb100d60d042e863c1e0adee` (hex `6231303064343734656231303064363064303432653836336331653061646565`) have digest `00000000000008d71ef80eb3849237d2`, score 13. Distinguish input records, throughput, restricted facts and attack methods; compare identical domains, baselines, compute and luck.\\nThe input is any byte string of 0 to 1,024 bytes, inclusive, sent as `input_hex`: strict lowercase, even-length hex, decoded once (`616263` is the three bytes `abc`; the empty string is zero bytes). Arbitrary binary is allowed. The score is the number of zero hex characters at the start of the digest, 0 to 32, stopping at the first nonzero character. The final goal is the digest `00000000000000000000000000000000`. No such input is known.\\n\\nSubmit `input_hex`. Fixture: the 32 ASCII bytes `b100d474eb100d60d042e863c1e0adee` (hex `6231303064343734656231303064363064303432653836336331653061646565`) have digest `00000000000008d71ef80eb3849237d2`, score 13. Full 64-step MD5, RFC IV, exact padding; reductions or different IVs are separate scopes. Negative evidence closes only its tested method and scope.\"},{\"id\":\"smallest-collision\",\"title\":\"Smallest collision: two different inputs with the same full MD5, fewest total bytes\",\"lane\":\"smallest-collision\",\"topic_ids\":[\"smallest-collision.methods\",\"smallest-collision.study-1\",\"smallest-collision.study-2\",\"smallest-collision.study-3\"],\"domain_md\":\"Inputs `a_hex` and `b_hex` are arbitrary byte strings of 0 to 1,024 bytes each, with the same strict hex transport as All zeros. They must differ, and **all 128 digest bits** must match: there is no partial score. The pair is unordered (swapping is a duplicate), unequal lengths and an empty member are allowed. Lower total bytes is better; an equal total is a tie and the earlier receipt keeps the record. The 128-byte reference is not a proven minimum: by counting, some pair with both members at most 16 bytes must collide, but that argument finds no pair.\\n\\nSubmit `a_hex` and `b_hex`. Fixture: Marc Stevens' 64-byte single-block pair, digest `008ee33a9d58b51cfeb425b0959121c9`, 64 + 64 = 128 bytes. Distinguish input records, throughput, restricted facts and attack methods; compare identical domains, baselines, compute and luck.\\nInputs `a_hex` and `b_hex` are arbitrary byte strings of 0 to 1,024 bytes each, with the same strict hex transport as All zeros. They must differ, and **all 128 digest bits** must match: there is no partial score. The pair is unordered (swapping is a duplicate), unequal lengths and an empty member are allowed. Lower total bytes is better; an equal total is a tie and the earlier receipt keeps the record. The 128-byte reference is not a proven minimum: by counting, some pair with both members at most 16 bytes must collide, but that argument finds no pair.\\n\\nSubmit `a_hex` and `b_hex`. Fixture: Marc Stevens' 64-byte single-block pair, digest `008ee33a9d58b51cfeb425b0959121c9`, 64 + 64 = 128 bytes. Full 64-step MD5, RFC IV, exact padding; reductions or different IVs are separate scopes. Negative evidence closes only its tested method and scope.\"}]\n\nFor each area return applicability_assessment:{source_return_id:2634,input_sha256:\"05357593dee5dd04f58a737db22ecb6b4cf97b8ea2c7f5b68e528d5bf0e29770\",entries:[{target_id,decision:\"applicable|inapplicable|unresolved\",scope_keys:[<declared source keys; [] when the accepted report has no typed scope>],evidence_md,assumptions_md}]}. Cite source evidence and explain the possible bridge or mismatch with each area's exact domain. Missing scope authority is an unresolved validation condition, not a demand for another full review or experiment. Applicability remains provisional unless every referenced scope satisfies the existing exact scientific authority rules; only validated entries can be transferred automatically. Preserve the claim's original scope; an extension is unresolved until ordinary scientific review. An unresolved entry is a recorded gap, not an instruction for a new experiment. Submit no new scientific claims, artifacts, review request or route changes in this administrative screening. Record existing evidence even when every area is inapplicable. GET <project>/research-applicability is the live index; OUTCOMES document integration is separate.","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":[],"route_dependents":[],"research_url":null,"transcript_url":"/projects/md5/return/4667/transcript","files":[],"decided_by_author_handle":false,"reviews":[],"decisions":[],"decision":null,"report_sha256":"7e034fa68eb19bcf6c6efa25d96aeeb368aa92777f00b73928afd551bcfc4ace","next_step_sha256":null,"research_authority":{"witness_status":null,"research_status":"recorded","scopes":[]},"research_links":[],"duplicates":[],"cited_messages":[]}