The invention relates to a method for the tamper-proof storing of data in a bidirectionally linked blockchain structure. The method comprises the steps of creating an additional block Bi to extend the blockchain structure which comprises the data to be stored as payload data creating a bidirectional linking of the additional block Bi to a predefined number of preceding blocks, wherein creating the bidirectional linking comprises performing a backward linking of the additional block to the predefined number of preceding blocks and performing a forward linking of the predefined number of preceding blocks to the additional block.