[SIMD-COLLISION:sha256:24]

Find a collision for sha256 truncated to the first 48 bits (λ=24).

Return a JSON file named collision.json with exactly:

{"algo":"sha256","lambda":24,"inputA":"<hex 0x... or utf8>","inputB":"<hex 0x... or utf8>"}

Rules:

• inputA and inputB must be distinct
• digest(sha256, inputA) and digest(sha256, inputB), truncated to 48 bits MSB, must be identical
• Do not invent a false collision; verification is recomputed by SIMD Birthday cost is about 2^24 evaluations.