'Superblock' ciphers? I'm a noob with very fragmental knowledge of basic crypto. So please excuse me if this question is really stupid.

If I understand everything correctly, there are two basic schemes for ciphers: a stream cipher, where every byte is encrypted by itself, and a block cipher, where some fixed length block of bytes is encrypted.

In a stream cipher encrypted bytes are in the same order as message bytes; in a block cipher bytes are mixed inside of a block but order of blocks stays the same.

So my question is: are there any kind of "superblock" ciphers where order of blocks in the ciphertext is different from plaintext? Does it even make sense to do this? Or there is no point because block ciphers are already secure enough?

Obviously such a 'superblock' cipher will not be suitable for any kind of streaming applicatons but may be for something like disk encryption?
There is already enough transposition in usual block ciphers to provide enough security. You could add a simple transposition cipher on top of a block cipher but there is little reason to do so.

It would be pretty easy to perform time based side channel on the cipher is it is spread across a disk or SSD. So that would already bring down the added security.

There may also be horrible performance decreases on certain media, as already mentioned in the comments.



Basically I don't see how such a scheme would add much security, and the implications of performing the transposition are too severe.

So yeah, I guess that block ciphers + common disk encryption schemes are already "secure enough" if there is such a thing.



Besides all that, if the block cipher gets broken, don't you think it would be relatively easy to put the blocks in the right position again?

Axapaxa also makes good observation on how this won't protect single block messages.