Re: [Qemu-devel] [PATCH v2] Describe flaws in qcow/qcow2 encryption in the docs

["Daniel P. Berrange" <berrange@redhat.com>]

On Wed, Jan 22, 2014 at 08:24:00AM -0700, Eric Blake wrote:
> On 01/22/2014 05:28 AM, Daniel P. Berrange wrote:
> 
> > 
> > Recommend against any use of QCow/QCow2 encryption, directing
> > users to dm-crypt / LUKS which can meet modern cryptography
> > best practices.
> > 
> > Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
> > ---
> >  qemu-doc.texi | 23 ++++++++++++++++++++---
> >  qemu-img.texi | 23 ++++++++++++++++++++---
> >  2 files changed, 40 insertions(+), 6 deletions(-)
> 
> > +
> > +@itemize @minus
> > +@item The AES-CBC cipher is used with predictable initialization vectors based
> > +on the sector number. This makes it vulnerable to chosen plaintext attacks
> > +which can reveal the existence of encrypted data.
> > +@item The user passphrase is directly used as the encryption key. A poorly
> > +choosen or short passphrase will compromise the security of the encryption.
> 
> s/choosen/chosen/ (both files)
> 
> > +In the event of the passphrase being compromised there is no way to change
> 
> and still my question whether this deserves a third @item.

I was considering this to be a result of using the passphrase as the
key. It does however read better if split out, so I've made that change.

Daniel
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