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

[Hagon]

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.
Thanks in advance
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Pozdrawiam / Regards
Bartosz Cichoński (Hagon)
e-mail: hagonbc at gmail.com
ICQ: 558807081
Windows Live (MSN): hagonbc at live.com
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XMPP/Jabber/GoogleTalk: hagonbc at gmail.com
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