Is shred single pass less secure than srm?

Question

i compared shred -n 1 -v --random-source=/dev/zero file.txt and srm -llvzd file.txt on 16gb file on hdd. ubuntu 14.04. both commands do single pass with zeros.

'srm' needed more than whole night while 'shred' finished in a few minutes. why? is shred less secure?

Answer 1

Check the deletion process of srm , I not sure but maybe shred only makes the overwriting. SRM Readme