Abstract: A method for storing hierarchical data protected by access data in an untrustworthy environment, wherein unique identification values of child nodes of at least one associated tree are determined for the data and are stored together with the data. The root node entry point is calculated based on the access data by means of a predeterminable calculation function in a volatile way, and the root node entry point represents a secret node entry point from which the identification value of a root node of the tree is subsequently calculated. The root node represents one of the child nodes in this tree, as a child node generation step is applied to generate the identification values of the child nodes based on one of the secret node entry points. A child node numbering set contains at least as many different elements as the number of child nodes to be generated is created or used.

Abstract: A method for storing hierarchical data protected by access data in an untrustworthy environment, wherein unique identification values of child nodes of at least one associated tree are determined for the data and are stored together with the data. The root node entry point is calculated based on the access data by means of a predeterminable calculation function in a volatile way, and the root node entry point represents a secret node entry point from which the identification value of a root node of the tree is subsequently calculated. The root node represents one of the child nodes in this tree, as a child node generation step is applied to generate the identification values of the child nodes based on one of the secret node entry points. A child node numbering set contains at least as many different elements as the number of child nodes to be generated is created or used.