On Oct 31, 2006 15:14 -0500, Nikolai Joukov wrote: > 1. One of the patches performs N overwrites with configurable patterns > (can comply with NIST and NISPOM standards). Because of the transaction > compaction we had to separately add overwriting as separate transactions. > Fortunately, the whole procedure is still atomic due to the orphan list. > The problem that we have right now is per-file syncing of dirty data > buffers between overwrites. We sync the whole device at the moment. Did anyone discuss doing this with crypto instead of actually overwriting the whole file? It would be pretty easy to store a per-file crypto key in each inode as an EA, then to "delete" the file all that would be needed would be to erase the key in a secure matter (which is a great deal easier because inodes don't move around on disk). The drawback is there is a runtime overhead to encrypt/decrypt the file data, but honestly, if people care about secure deletion don't they also care about security of the undeleted data also? By having an (unknown to the user) per-file crypto key then if the file is deleted the user can also plausibly deny the ability to recover the file data even if they are forced to surrender their key. Cheers, Andreas -- Andreas Dilger Principal Software Engineer Cluster File Systems, Inc. - To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
