What is the earliest possible date that ECC-256 could be cracked?

The earliest plausible date for cracking ECC-256 (e.g., secp256k1 used in Bitcoin/Ethereum) with a cryptographically relevant quantum computer (CRQC) is optimistically late 2028–2029 in highly aggressive scenarios, but this remains highly speculative and uncertain. More conservative expert consensus points to the early-to-mid 2030s. No such machine exists today, and substantial engineering work is still required.<grok:render card_id="018556" card_type="citation_card" type="render_inline_citation...