> A blockchain[1][2][3]—originally, block chain[4][5][6]—is a distributed database that maintains a continuously-growing list of data records hardened against tampering and revision. It consists of data structure blocks—which hold exclusively data in initial blockchain implementations,[7] and both data and programs in some of the more recent implementations—with each block holding batches of individual transactions and the results of any blockchain executables.[8][better source needed] Each block contains a timestamp and information linking it to a previous block.[9]