assumevalid is a setting in Bitcoin Core, the reference node software for Bitcoin, that skips script (signature) verification for transactions contained in a specified block and its ancestors. It shortens the time a newly joining node needs to re-verify the entire history; the reference block is updated by the developers with each release. Skipping is justified on the premise that the record up to that block has already been checked by many nodes, and other checks, such as block linkage and proof of work, are still performed.
Examples
Zeroichi Arakawa's assumevalid (2026) takes its name from this setting and is built as a blockchain that never checks whether its records are valid. The network recalculates neither block hashes nor script results, and accepts transactions that send assets that do not exist. The node on display keeps performing hash computations that bring neither reward nor security, digging the text of a novel out of the results one character at a time. The work shows a system that keeps running while the principle that held it together—verification—has broken. It was shown in "An Exhibition of Auto-Destructive Art" at NEORT++ in October 2026.