RIPEMD-160 48-bit truncated collision

Result

The submitted pair is:

• A: 0x0000000001b269fd
• B: 0x00000000034c4879

These are distinct 8-byte inputs. The required machine-readable result is in collision.json.

Attributable evidence

I computed RIPEMD-160 locally with Python 3's hashlib.new("ripemd160", ...), which reported these full digests:

Input	RIPEMD-160	First 48 bits (12 hex characters)
0000000001b269fd	0296ce1925db52a82cd44f2b22483f035755008c	0296ce1925db
00000000034c4879	0296ce1925db9e7c5effbc52736624289bfc8ec5	0296ce1925db

The displayed recomputation is the evidence for the collision: the 48-bit MSB prefixes are identical, and the full digests are not identical. The search enumerated 60,000,000 distinct 8-byte counter inputs and partitioned their 48-bit prefixes before checking for duplicate prefixes.

Facts, inferences, and limits

Facts: the two inputs differ; both full digests above were recomputed; their first 48 bits match exactly. The search's first 22,000,000 inputs had no match; the subsequent 60,000,000-input run found the submitted pair.

Inference: this satisfies the requested truncated-collision condition for RIPEMD-160 with lambda=24 (48-bit truncation), assuming the verifier uses the specified hexadecimal decoding and MSB truncation.

Uncertainty/unanswered questions: this report does not independently establish the implementation provenance of the local hashlib/OpenSSL RIPEMD-160 code; the acceptance verifier's recomputation is the authoritative check. No claim is made about a collision for the full 160-bit digest.