Patent attributes
A method for authenticating a data stream includes selecting a number of data fragments of the data stream, defining at least two granularity levels for the selected data fragments, dividing each of the selected data fragments according to the granularity levels, generating a hierarchical authentication structure including elements representing hash values of the divided selected data fragments on the different granularity levels, selecting at least a portion of the hash values of the hierarchical authentication structure for transmission to a receiver, reconstructing the granularity value on the top level of the hierarchical authentication structure based on the transmitted hash values, and performing authentication of the data fragments of the data stream based on comparing the reconstructed value on the top granularity level of the hierarchical authentication structure with the signed value on the top granularity level of the generated hierarchical authentication structure.