Re: AES design - can you help me to understand

Sorry, Tom
I understand your suggestion.

The paper has a section called, "Key-alternating block ciphers".
The paper distinguishes this from "Iterative block cipher".
The paper gave formulations for the same.

I may have incorrectly assumed that the first was the strategy used in AES?

I made a strong attempt [and an a priori language apology]
to use the main keywords read in the paper.

But, I understand, and will indeed try to take you general advice anyway.
I mean it's generally good advice.



"Tom St Denis" <tomstdenis@xxxxxxxxx> wrote in message
news:1151675647.724687.168120@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
kentucky wrote:
Not sure but I think the paper was suggesting that
subbyte
shiftrows
mixcolumns
May be a key independant scrambling bround?

Um look at the AES design carefully, you do a "AddRoundKey" before you
start the loop of rounds. So the data is "keyed" before you even get
into the unkeyed parts of the first round.

addroundkey

And this one may be a key dependant scrambling round similar
to what DES uses in every round?

AddRoundKey is *NOT A ROUND* it's a function that is PART OF the AES
round.

Both AES and DES take your secret key and stretch it with a key
schedule algorithm [AES and DES use different algorithms] to make the
round keys.

In the case of AES the key is added to the block, in the case of DES
it's added to the input to the Feistel round function.

Together, "key-alternating" round strategy?

Again, you lost me. Stop making up terms.

Listen,

IF YOU DIDN'T READ IT IN A PAPER OR BOOK THEN IT'S PROBABLY NOT A
CRYPTOGRAPHIC TERM SO DON'T USE IT.

It's really that simple.

I suggest you learn how one works then the other. Stop trying to
compare what AES does to DES. DES is a balanced Feistel, AES is a
substitution permutation network. They work differently.

If you really want to compare DES to another cipher compare it to CAST5
or Twofish or something. But I highly suggest you focus on DES *AND
THEN* AES.

Tom



.

Relevant Pages

  • Re: Does "bitslice AES" make sense?
    ... > but are free in bitslice. ... > AES, on the other hand, is usually implemented entirely with lookup ... I partialy refute the argument that DES is bit oriented, ... for each additional round and each ...
    (sci.crypt)
  • Re: 2006/467 Chang Yung: silly?
    ... block cipher with the same output size and running it in one of the 12 ... of AES constants, or on the mixing in the final AES round. ...
    (sci.crypt)
  • Re: AES design - can you help me to understand
    ... DES uses a key dependant transformation in every round? ... Every round of AES uses key material derived from the secret key ...
    (sci.crypt)
  • Re: AES design - can you help me to understand
    ... DES uses a key dependant transformation in every round? ... If one ran DES and AES for and equal number of rounds - say 10: ...
    (sci.crypt)
  • Re: AES design - can you help me to understand
    ... And this one may be a key dependant scrambling round similar ... AddRoundKey is *NOT A ROUND* it's a function that is PART OF the AES ... Both AES and DES take your secret key and stretch it with a key ...
    (sci.crypt)