[Qt-interest] cascaded encryption with AES, Twofish, Serpent - how to create keys in secure way

[Diego Iastrubni]

Barking at the wrong tree... but...

On Mon, Feb 22, 2010 at 4:55 PM, Hagon <hagonbc at gmail.com> wrote:

> Hello!
> I'm developing a simple app using QT and Botan. I would like to implement
> "cascaded encryption" using  AES, Twofish and Serpent (like in truecrypt).
> I know that I must create a "Pipe" or "Chain" with three cipher objects.
> The encryption scheme should use a single password for  all the ciphers
> listed.
> How to create keys for these three ciphers from the password in secure
> way??? I know that using single key for multiple encryption algorithms is
> rather insecure... This will be an open-source app.
>

Whats the point of using a single password/passpharse for 3 encryptions? You
are loosing the security "upgrades"... What am I missing?
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