{"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":"c4dd5205-24f8-4022-80b6-cde005827c2f","kind":"skill:research-report","nodes":[{"acceptedSubmissionHash":"ad4ccfc1898cb324f63973370740a9f74024f1997500cf322c36dcc0c5d02ff2","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:ripemd160:24]\nFind a collision for ripemd160 truncated to the first 48 bits (λ=24).\nReturn a JSON file named collision.json with exactly:\n{\"algo\":\"ripemd160\",\"lambda\":24,\"inputA\":\"<hex 0x... or utf8>\",\"inputB\":\"<hex 0x... or utf8>\"}\nRules:\n- inputA and inputB must be distinct\n- digest(ripemd160, inputA) and digest(ripemd160, inputB), truncated to 48 bits MSB, must be identical\n- Do not invent a false collision; verification is recomputed by SIMD\nBirthday cost is about 2^24 evaluations.","parentJobId":null,"planHash":"db8cf59269792af61e6af2b5ee3f86a9745dd031d74535fb14290fe873f6a5ff","previousHash":"0000000000000000000000000000000000000000000000000000000000000000","projectId":"c4dd5205-24f8-4022-80b6-cde005827c2f","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":"51203","feedbackHash":"48c5852e9fcc3dca2db94670878e73759e8b717ea173abae0ae417f7cc814165","nodeKey":"research_report","submissionHash":"ad4ccfc1898cb324f63973370740a9f74024f1997500cf322c36dcc0c5d02ff2","tag1":"verification:structural","tag2":"acceptance-v2","value":1}],"site":null,"snapshotHash":"7dc01dac47a8a05a69bb7d4e245d5bd8ff3557f640927372db7ca670224424a1","state":"completed","submissions":[{"artifacts":[{"bytes":2380,"hash":"7d6b921b602708593d6a443b25a74b6126234684302891adf9373ed16ca1298d","mediaType":"text/markdown","name":"report","path":"artifacts/report.md"}],"attempt":1,"bundleHash":"ae09d5dc3e98f4e80c8a59182f5bc99aaf05516a66f5a8c9b311e83c4219cf68","device":"896d1238054266ca","findings":[],"hash":"ad4ccfc1898cb324f63973370740a9f74024f1997500cf322c36dcc0c5d02ff2","nodeId":"a37429b0-7863-4ead-ad1d-3557e0c016f8","outcome":"completed","summary":"I found a collision for RIPEMD-160 truncated to its first 48 bits, and checked it with three separate implementations.\n\n`collision.json`:\n```json\n{\"algo\": \"ripemd160\", \"lambda\": 24, \"inputA\": \"rmd160-9467736\", \"inputB\": \"rmd160-16123348\"}\n```\n\n| input (UTF-8) | RIPEMD-160 digest |\n|---|---|\n| `rmd160-9467736` | **`12831c48ee1a`**`c8a15823d8ef3a1be1665ccfac1a` |\n| `rmd160-16123348` | **`12831c48ee1a`**`63193ea415ec0aa3b910ade306a0` |\n\nThe two inputs are different and the first 6 bytes (48 bits) of their digests match. The full digests differ.\n\n- **Search:** `scripts/find_collision.py` hashes `rmd160-0`, `rmd160-1`, … in order and stops at the first repeated 48-bit prefix. It found this one after 16,123,349 hashes (about 2^23.9), taking 1m48s. That fits the expected cost of about 2^24.3. Rerunning the script gives the same pair.\n- **Check:** Python's `hashlib`, the `openssl dgst -ripemd160` command, and a pure-Python RIPEMD-160 I wrote all gave the same two digests. Before using the pure-Python version, I tested it against the published test vectors from the RIPEMD-160 reference page.\n- **Not checked:** I couldn't run the task's own \"SIMD\" checker. I'm assuming it reads inputs without a `0x` prefix as UTF-8 text, which is what the task format describes.\n\nFiles:\n- **Committed** (commit `10165ed`): `collision.json`, `scripts/find_collision.py` and `README.md` (the question, the answer, how to reproduce it, and its limits). Git had no identity set, so I made the commit as `ringfeng604 <ringfeng604@gmail.com>`, set for that commit only. I didn't change the git config.\n- **Left untracked**, as required: `artifacts/report.md`, which separates facts, inferences, uncertainty and unanswered questions. It's already excluded by `.git/info/exclude`, as is `test/scratch/`, which holds the check script.","treeHash":"b906cbf2c9a0fc2829a3796b28a3ca89709c8a23","usage":{"cachedInputTokens":185379,"inputTokens":16,"model":"claude-opus-5-5","outputTokens":6751,"runtime":"claude","turns":8,"wallClockMs":188651}}],"verification":[{"checks":[],"detail":"paths and tree verified; no suite was run for this kind of work","evaluation":"structural","profile":"none","status":"accepted","submissionHash":"ad4ccfc1898cb324f63973370740a9f74024f1997500cf322c36dcc0c5d02ff2","verifiedTreeHash":"b906cbf2c9a0fc2829a3796b28a3ca89709c8a23","verifierVersion":"0.1.0+41305fb5"}]}