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There are some reasons you'd want to encrypt even without a secret key. One is it makes it easier to erase data (just erase the key). It also makes bit flip er
by astrange 1y ago
There are some reasons you'd want to encrypt even without a secret key. One is it makes it easier to erase data (just erase the key).
It also makes bit flip errors a lot more obvious, which is another way of saying harder to ignore, so that can go either way.
- ranger_danger 1y agoCan't bit flip errors also destroy encrypted volumes much more easily?
- dgoldstein0 1y agoI think it depends. Encrypted filesystems typically encrypt contents of each file separately - that way you don't need to read / write the whole disk to read it write any individual file contents. Of course that means metadata may be in plain text or may be separately encrypted - again possibly folder by folder instead of all metadata at once. Exact details would vary with different file system encryption schemes. Whereas if you image the disk and encrypt the image properly, that gives you all the great confidentially guarantees but no random access.
- astrange 1y ago> Encrypted filesystems typically encrypt contents of each file separately - that way you don't need to read / write the whole disk to read it write any individual file contents. Ah, that's not true of "full disk encryption". It usually encrypts the disk blocks. File-based encryption is stronger; you can use different protection classes on different files, you can use authenticated encryption, etc. iOS does it this way and I assume other systems have caught up, but don't know any in particular.
- tliltocatl 1y agoFile-based encryption leaks metadata (which in some cases is bad enough to render it unusable).
- astrange 1y agoNo one said you had to leave the FS itself unencrypted.
- cyphar 1y agoMost FDE systems are not authenticated so you would only lose one block (16 bytes for AES). Can this be bad? Yeah, but it's not that bad for data recovery.
- cyphar 1y agoNot to mention that most drives start having issues with dead sectors rather than bitflips, and that's (usually) 4K.
- shim__ 1y agoEncryption does not make bit flips obivous, authenticated encryption would.
- rawling 1y agoA single bit flip would mess up the block, and hopefully the rest of the stream and the padding, no?
- MattPalmer1086 1y agoMost unauthenticated encryption modes only mess up a few bits of a block, sometimes the following block too. A few only flip the exact bit in the plaintext.