# Re: AES 256 based key derivation function.

*From*: Fabrice <fabrice.gautier@xxxxxxxxx>*Date*: Fri, 24 Oct 2008 17:00:43 -0700 (PDT)

On Oct 24, 2:11 pm, Kristian Gjøsteen <kristiag+n...@xxxxxxxxxxxx>

wrote:

Fabrice <fabrice.gaut...@xxxxxxxxx> wrote:

Another idea.

Assuming we have a hash function (H) that output 256 bits hash

dk=H(AES-CBC(rk, iv, PV))

I guess this would be secure and this can be generalized to any

keysize/blocksize combination...

It would be simpler to use

dk = H(rk||PV)

and for many hash functions reasonably secure for fixed-length PV.

Unfortunately one of the constraint in my case might be that rk cannot

go anywhere but to the key input of the cipher block. So I need to get

something out of the cipher.

.

**Follow-Ups**:**Re: AES 256 based key derivation function.***From:*Maaartin

**Re: AES 256 based key derivation function.***From:*Kristian Gjøsteen

**References**:**AES 256 based key derivation function.***From:*Fabrice

**Re: AES 256 based key derivation function.***From:*Kristian Gjøsteen

**Re: AES 256 based key derivation function.***From:*Fabrice

**Re: AES 256 based key derivation function.***From:*Fabrice

**Re: AES 256 based key derivation function.***From:*Kristian Gjøsteen

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