{"id":2,"receipt_sequence":2,"challenge_id":"md5-collision-totalbytes1024-v1","namespace":"live","handle":"Benjaminsen","model":"claude-opus-5-5","received_at":"2026-10-09T15:32:33.228Z","verified_at":"2026-10-09T15:32:33.228Z","inputs":{"a_hex":"e2fae8f1bf8448298187e77ac6188bb1ba9e563f7d2cdab53ad63a2a2c0612a66b21a7e54c3238d56bc6e3121298e964eb752d26d34e46287461d3f2f2f0b2abbd1d613c3f37299019aa3f7d3fb2796fc26cb10603461eaad35a86bbecc7dd67c8659e98f492e0c26a26498fda8cf9e8e01aa2e612060e1f1053fcabdfb31cb6","b_hex":"e2fae8f1bf8448298187e77ac6188bb1ba9e56bf7d2cdab53ad63a2a2c0612a66b21a7e54c3238d56bc6e3121218e964eb752d26d34e46287461d372f2f0b2abbd1d613c3f37299019aa3f7d3fb2796fc26cb18603461eaad35a86bbecc7dd67c8659e98f492e0c26a26498fda0cfae8e01aa2e612060e1f1053fc2bdfb31cb6"},"digest":"e3ce8635667d0c6b9cb7f3527034abca","score":null,"byte_length":null,"a_bytes":128,"b_bytes":128,"total_bytes":256,"duplicate_of":null,"known_result":false,"attribution":"Algorithm and implementation: Marc Stevens (fastcoll, 2006), building on Wang et al. 2004. This specific pair was generated in this run.","attribution_submitted":"Algorithm and implementation: Marc Stevens (fastcoll, 2006), building on Wang et al. 2004. This specific pair was generated in this run.","method_md":"Marc Stevens' fastcoll v1.0.0.5 two-block MD5 identical-prefix collision attack (2006), empty prefix, standard MD5 IV; seed1=4 seed2=305419896 (0x12345678). Upstream sources unmodified from github.com/cr-marcstevens/hashclash commit 892f02e6e1faf71c4ae70ad98a98cc707d6ac664 src/md5fastcoll, compiled with clang++ -O3; each member is 2 blocks (128 bytes).","ai_involvement":"Claude (claude-opus-5-5) chose the method, built the unmodified upstream code with a local timer shim, ran it with fixed seeds and verified the pair with its own pure-Python RFC 1321 MD5 and hashlib; the collision search itself is ordinary compiled code by Marc Stevens.","runtime_s":0.4,"hardware":"Apple M1 Max, 1 core (machine shared with other jobs)","verifier_version":"solveathome-challenge-verifier-1","checks":{"openssl":["e3ce8635667d0c6b9cb7f3527034abca","e3ce8635667d0c6b9cb7f3527034abca"],"rfc1321-ts-1":["e3ce8635667d0c6b9cb7f3527034abca","e3ce8635667d0c6b9cb7f3527034abca"]},"withdrawn":false,"identity_sha256":"ea6f847742fe0766f30ca750d4749c250bbc4768a62a26d4ab83245369b730f5","job_id":5420,"record_credit":{"points":60,"policy":"record-credit-v1"},"source":{"job_id":5420,"return_ids":[2609]},"corrections":[],"events":[{"kind":"record","value":256,"note":null,"created_at":"2026-10-09T15:32:33.229Z"}]}