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Hi everybody;

I am new in VDHL and crypto also. I would like to implement the
Davies-meyer HASH function ( Hi = Emi(Hi-1)+Hi-1 ) in VHDL. The problem
I am having is that: The block cipher I am having (Kasumi) have 64 bits
input and output and the HASH function(SHA1) is having 160 bits output.
I don't know how can I manage an agrement between them in order to
implement the Davies-meyer.
Can anyone help me in getting an arrangement of those functions or
indicate where I can find literatures or implementations about this.
Thanks all and nice day.
Adam.

Adam,
I'm confused by your use of SHA1 in your post. Perhaps looking at

http://en.wikipedia.org/wiki/Hash_fu..._block_ciphers

and rephrasing your question would help me understand what you want.

This method(Davies-Meyer) takes a block cipher and creates
a hash fucntion from it. The key size of the block cipher is the size
of the message block being hashed, whereas the message block size of
the stream cipher is the hash value size.

alan

Adam wrote:
> Hi everybody;
>
> I am new in VDHL and crypto also. I would like to implement the
> Davies-meyer HASH function ( Hi = Emi(Hi-1)+Hi-1 ) in VHDL. The problem
> I am having is that: The block cipher I am having (Kasumi) have 64 bits
> input and output and the HASH function(SHA1) is having 160 bits output.
> I don't know how can I manage an agrement between them in order to
> implement the Davies-meyer.
> Can anyone help me in getting an arrangement of those functions or
> indicate where I can find literatures or implementations about this.
> Thanks all and nice day.
> Adam.

ajjc schrieb:

> Adam,
> I'm confused by your use of SHA1 in your post. Perhaps looking at
>
> http://en.wikipedia.org/wiki/Hash_fu..._block_ciphers
>
> and rephrasing your question would help me understand what you want.
>
> This method(Davies-Meyer) takes a block cipher and creates
> a hash fucntion from it. The key size of the block cipher is the size
> of the message block being hashed, whereas the message block size of
> the stream cipher is the hash value size.
>
> alan

Hi Alan,

Thanks a lot; your message cleared a lot of confusions in my mind. I
was actually miss-lead because I have been given a wrong Davies-meyer
diagram containing a Hash function.
Now everything is clear and once more thanks.

Adam.