TAMPER-EVIDENT REWRITE OF A MULTIPLE-LINK CRYPTOLOGIC BLOCKCHAIN

A method comprising: accessing, using circuitry, a key secret for a blockchain stored in a memory; the method being characterized by: determining, with the circuitry, to rewrite original data in a selected block of the blockchain with altered data that is different than the original data previously stored in the selected block; determining, with the circuitry and using the key secret, collision data including the altered data, the collision data being different from the original data and coding-consistent with a previously determined integrity output stored within a specific block of the blockchain that follows the selected block, the previously determined integrity output generated responsive to and coding-consistent with the original data; and rewriting, with the circuitry, the selected block with the collision data.