Bug 322369

This is an improvement request. Many k3b users use it to turn installation iso files to disk, these iso files are reported with sha256sum hashes and no longer with md5sum. It would be useful if the K3B configuration preferences allowed the default md5sum hash for the "Burn Image" page to be replaced with sha256.  Since sha256 is slower it should only be an 'opt-in' option and not the default, which should remain md5sum.

Reproducible: Always

Steps to Reproduce:
1. start k3b, access "Burn Image" from menu
2. select an iso image file
3. k3b uses md5sum to show hash of the file and progress bar shows rate of progress
Actual Results:  
N/A (new feature req.)

Expected Results:  
N/A (new feature req.)

Allow for an option in the Preferences menu (Settings -> Configure K3B -> Advanced ), probably in the 'Advanced' section for opting into using sha256 instead of md5