Shredo

Shredo is a beautiful, functional file-shredding utility. It permanently shreds files, folders, and external volumes’ contents to keep information secure and impossible for anyone to retrieve. Depending on security level and data-erase speed, you have 3 shredding methods at your disposal:

1. 1-pass – Offers good security and quickest erase of data. It deletes access information to your files and writes random bytes over the data once.
2. 7-pass – Slower speed, but better security than 1-pass. Writes over data 7 times, based on US Department of Defence (DoD) 5220-20 M standard algorithms.
3. 35-pass – Slowest, but offers the best security. Erases file access info and writes over the data 35 times, based on the Gutmann method for deletion.