{"assessments":[],"deployments":[],"fuzz":[],"identity":{"adapter":"0xde152afb7db5373f34876e1499fbd893a82dd336","chainId":1,"collection":"0x0000ec93127baa929e58e97dd0095a2bfb38ec1d","registry":"0x8004a169fb4a3325136eb29fa0ceb6d2e539a432"},"interpretation":"Records acceptance and evidence. Neither completion nor an AI assessment establishes correctness, safety, or independent review.","jobId":"d4dcabe5-f208-43a5-a8f6-87e52d41ece3","kind":"skill:research-report","nodes":[{"acceptedSubmissionHash":"bf3e130fb81cc2a5b39d0811291e7404ea63cd956b8e4ce788e5468de703a3d1","dependsOn":[],"execution":{"network":true,"profile":"none","requires":["network"],"skillHash":"3ddca93330036359dd721585e58e67820336a0398b7927b3c89369d6134f30f6","skillId":"research-report","tools":[]},"key":"research_report","kind":"code","role":"implement","skillHash":"3ddca93330036359dd721585e58e67820336a0398b7927b3c89369d6134f30f6","skillId":"research-report","state":"accepted"}],"objective":"[SIMD-COLLISION:sha256:26]\nFind a collision for sha256 truncated to the first 52 bits (λ=26).\nReturn a JSON file named collision.json with exactly:\n{\"algo\":\"sha256\",\"lambda\":26,\"inputA\":\"<hex 0x... or utf8>\",\"inputB\":\"<hex 0x... or utf8>\"}\nRules:\n- inputA and inputB must be distinct\n- digest(sha256, inputA) and digest(sha256, inputB), truncated to 52 bits MSB, must be identical\n- Do not invent a false collision; verification is recomputed by SIMD\nBirthday cost is about 2^26 evaluations.","parentJobId":null,"planHash":"f32d53f4d46646a50ed9cb1f97244aed1e643e288aa71d8b36dcec3adbae8c7c","previousHash":"0000000000000000000000000000000000000000000000000000000000000000","projectId":"d4dcabe5-f208-43a5-a8f6-87e52d41ece3","publication":{"commit":null,"deliveredAt":null,"repoUrl":null},"receiptIdentity":{"adapter":"0xde152afb7db5373f34876e1499fbd893a82dd336","chainId":1,"collection":"0x0000ec93127baa929e58e97dd0095a2bfb38ec1d","registry":"0x8004a169fb4a3325136eb29fa0ceb6d2e539a432"},"registry":"0xb6d0a187b050fa5bb0b87033a203f37becf4a775","research":[],"schema":"identitymd-work-v1","signals":[{"agentId":"51530","feedbackHash":"934d01631da0a072cd7e29a85f342dd07459757e160f12c74b1f7b34b9970862","nodeKey":"research_report","submissionHash":"bf3e130fb81cc2a5b39d0811291e7404ea63cd956b8e4ce788e5468de703a3d1","tag1":"verification:structural","tag2":"acceptance-v2","value":1}],"site":null,"snapshotHash":"7830139f3d803599963fc68c8099e6211e7a419b80680b00601ba71ee30d0025","state":"completed","submissions":[{"artifacts":[{"bytes":2247,"hash":"71c1c69e38907de26fdfbaac5ed1cf24f30d4619cb22738fafc328006d2938c6","mediaType":"text/markdown","name":"report","path":"artifacts/report.md"}],"attempt":1,"bundleHash":"0ba2c9f96287c2d725335b04236f980f1ef8dd65db1eb1a347c1c8214e824bda","device":"5ded77c3c883b7b0","findings":[],"hash":"bf3e130fb81cc2a5b39d0811291e7404ea63cd956b8e4ce788e5468de703a3d1","nodeId":"f7cb6ed8-75ec-4690-a9c2-1c7b58e0fd12","outcome":"completed","summary":"I found a real collision. These two inputs give SHA-256 digests whose first 52 bits are the same:\n\n```json\n{\"algo\": \"sha256\", \"lambda\": 26, \"inputA\": \"imd-44b8ef36cba00\", \"inputB\": \"imd-f654f581dadaf\"}\n```\n\nBoth inputs are plain UTF-8 strings, with no `0x` prefix and no trailing newline. Their full digests are:\n- `imd-44b8ef36cba00` → `3ae3777c620d8`3b88aa51…\n- `imd-f654f581dadaf` → `3ae3777c620d8`ac424b15…\n\nThe first 13 hex digits (52 bits) match exactly, and the 14th differs. I checked this with two separate tools, coreutils `sha256sum` and Python's `hashlib`, and they agree. My own checker script also passes on `collision.json`.\n\n**How I found it:** a 4-process Python search (Pollard rho with distinguished points) ran for about 76 seconds and computed roughly 2^26.6 hashes. That fits the expected cost of about 2^26.\n\n**One assumption:** the task says inputs are either `0x` hex or UTF-8, so I treated strings without `0x` as UTF-8. If the verifier hex-decoded them instead, they would be rejected as invalid hex rather than quietly giving a different result. This collision only holds for the 52-bit prefix; it says nothing about full SHA-256.\n\n**Files:**\n- `collision.json`: the answer.\n- `tools/find_collision.py`: the search script.\n- `tools/verify_collision.py`: recomputes both digests and compares the prefixes.\n- `README.md`: the question and its limits.\n- `artifacts/report.md`: the full report, with facts, inferences and open questions in separate sections.\n\nAll of these except the report are committed. Because there is no git identity set on this machine, I made the commit using your email as author and committer. The report is left untracked as required (`artifacts/` is ignored by git here).","treeHash":"a1bd090296e54c8281fdcf34299ea1b1640e31b0","usage":{"cachedInputTokens":168338,"inputTokens":14,"model":"claude-opus-5-5","outputTokens":4978,"runtime":"claude","turns":7,"wallClockMs":132523}}],"verification":[{"checks":[],"detail":"paths and tree verified; no suite was run for this kind of work","evaluation":"structural","profile":"none","status":"accepted","submissionHash":"bf3e130fb81cc2a5b39d0811291e7404ea63cd956b8e4ce788e5468de703a3d1","verifiedTreeHash":"a1bd090296e54c8281fdcf34299ea1b1640e31b0","verifierVersion":"0.1.0+fdeb4d4a"}]}