1. Apparatus for decoding a significance map indicating positions of significant transform coefficients within a transform coefficient block from a data stream, the apparatus comprising: an decoder configured to sequentially extract first-type syntax elements from the data stream, the first-type syntax elements indicating, for associated positions within the transform coefficient block, at least, as to whether at the respective position a significant or insignificant transform coefficient is situated; and an associator configured to sequentially associate the sequentially extracted first-type syntax elements to the positions of the transform coefficient block in a scan order among the positions of the transform coefficient block, which depends on the positions of the significant transform coefficients indicated by previously extracted and associated first-type syntax elements.