1. A computerized method for signature-based unsupervised clustering of data elements, comprising: receiving a plurality of clusters, each cluster comprising at least a data element; generating an upper triangular matrix respective of the clusters; generating a signature for each of the clusters, wherein a signature is generated from multiple patches of a multimedia data element, wherein multiple patches are of random length and random position within the multimedia data element; generating a match score between each of two different clusters; storing the match score in a cell of the upper triangular matrix corresponding to the two clusters; determining whether any of the match scores is above a predefined threshold value; clustering every two clusters that are determined to have a score above a predetermined threshold; and repeating the generation of an upper triangular matrix respective of the clusters until a single cluster is reached, wherein the clustering on the respective generated signatures creates clusters that include a collection of signatures respective of the multimedia data elements.