Security Basics mailing list archives
Re: 256-bit Camellia vs 256-bit AES - Which is better?
From: Shailesh Rangari <shailesh.sf () gmail com>
Date: Wed, 18 Feb 2009 22:08:19 -0500
I was mentioning Fiestel Network in general. The comment wasn't implied directly on AES and/or DES specifically. As such I would still maintain that the essence of Fiestel remains in its simplicity of Encryption and Decryption process which are reversal of the process itself.
"The Feistel structure has the advantage that encryption and decryption operations are very similar, even identical in some cases, requiring only a reversal of the key schedule" -Wikipedia
Precisely the similarities between AES and DES are -AES Round Key addition corresponds to DES XOR of subkey material with the input to function f. AES Mixcolumn corresponds to DES XOR of function f output with the left half block.
AES ByteSub corresponds to function f in DES. AES ShiftRow corresponds to DES permutation P. Regards, Shailesh On Feb 18, 2009, at 12:01 PM, Terra Frost wrote:
On Tue, Feb 17, 2009 at 6:08 PM, Shailesh Rangari <shailesh.sf () gmail com > wrote:- both use the 'Fiestel Network' (first used in Lucifer & DES). Its essenceis Decryption is done by Reversing the order of Encryption.That's incorrect. In DES, the only difference between the encryption and decryption is the order in which the round keys are used. That's pretty much the definition of a Fiestel Network. In AES, in contrast, the differences between encryption and decryption are a bit more pronounced. Take a look at fips-197.pdf#page=25 and fips-197.pdf#page=19. The only function shared by both is AddRoundKey. SubBytes and InvSubBytes differ in that they use different S-Boxes, InvShiftRows and ShiftRows shift the rows in opposite directions, and MixColumns and InvMixColumns with a different fixed polynomial. fips-197.pdf can be found here: http://csrc.nist.gov/publications/fips/fips197/fips-197.pdf
Current thread:
- 256-bit Camellia vs 256-bit AES - Which is better? Chip Panarchy (Feb 17)
- Re: 256-bit Camellia vs 256-bit AES - Which is better? Shailesh Rangari (Feb 18)
- Re: 256-bit Camellia vs 256-bit AES - Which is better? Terra Frost (Feb 18)
- Re: 256-bit Camellia vs 256-bit AES - Which is better? Shailesh Rangari (Feb 19)
- Re: 256-bit Camellia vs 256-bit AES - Which is better? Terra Frost (Feb 18)
- Re: 256-bit Camellia vs 256-bit AES - Which is better? Terra Frost (Feb 18)
- Re: 256-bit Camellia vs 256-bit AES - Which is better? maddaemon () gmail com (Feb 18)
- Re: 256-bit Camellia vs 256-bit AES - Which is better? Shailesh Rangari (Feb 18)