Cryptography Stack Exchange
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Questions tagged [rijndael]

Rijndael is a family of symmetric block-ciphers with block and keys sizes of 128, 160, 192, 224, or 256 bits.

Rijndael is a family of symmetric block-ciphers with block and keys sizes of 128, 160, 192, 224, or 256 bits.

The Rijndael block-cipher (standardised with a block size of 128 bits) was the winner of the Advanced Encryption Standard contest.

See the wikipedia page for more information.

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Difference between Rijndael 128 / 256 blocksize implementations? (and impact of block size in general)

Can anyone shed some light onto the advantages/disadvantages of using Rijndael with 256-bit block size, as opposed to the 128-bit (AES) implementation? (please note: I'm not referring to key-size here). These are standard implementations in…
hunter
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Choice of multiplication polynomial in Rijndael s-box affine mapping

The Rijndael specification details the design choices for the s-box in section 7.2. They describe the choice of affine mapping as follows: We have chosen an affine mapping that has a very simple description per se, but a complicated algebraic…
Richie Frame
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Can neural cryptanalysis be applied to AES?

In this Wikipedia article about Neural cryptography (section applications) it states: In 1995, Sebastien Dourlens applied neural networks to cryptanalyze DES by allowing the networks to learn how to invert the S-tables of the DES. The bias in DES…
AleksanderCH
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AES - What is the advantage of a 256-bit key with a 128-bit block cipher?

I'm just trying to wrap my mind around the decision to select the 128-bit Rijndael as the AES cipher, even with 192-bit and 256-bit keys. Even with a 256-bit key, you only get 2^128 possible outputs per 128-bit block, thus kind of rendering the…
Scott Arciszewski
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Is there a contingency plan in the event of a catastrophic attack on AES?

NIST selected Rijndael in 2000 to be AES. In a paper from the Serpent authors, they mention that there was the possibility of choosing a second cipher as a backup in the case of any severe breaks: I believe that there should be only one standard.…
forest
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Is there any compelling or logical reason to use AES-192 over AES-128 but not use AES-256?

I have been trying to find a case where AES-192 is used over AES-128 but AES-256 is not used. There are many questions about AES here (I liked this one AES-128/192/256), but from the actual application side, I was unable to determine any cases where…
b degnan
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Does changing the order of the steps within a round affect the security of AES?

I was trying to understand the internal structure of AES (Advanced Encryption Standard) The Standard order of steps within a round: Substitute Bytes Shift Rows Mix Columns Add Round Key Substitute Bytes, Shift Rows & Mix Columns satisfies the two…
Atinesh Singh
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How does the key schedule of Rijndael looks for keysizes other than 128 bit?

It said in Wikipedia that: [....] Rijndael can be specified with block and key sizes in any multiple of 32 bits, with a minimum of 128 bits. The blocksize has a maximum of 256 bits, but the keysize has no theoretical maximum. How would the key…
goldroger
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Is standardizing a modified AES a good idea?

"Recently" the Ukraine standardized a new block cipher Kalyna, which according to the abstract of"A New Encryption Standard of Ukraine: The Kalyna Block Cipher" by Oliynykov et al. (warning: the paper contains a lot of test-vectors) is basically a…
SEJPM
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Advantage of $\operatorname{GF}(2^8)$ over $\mathbb Z/2^8\mathbb Z$ in AES/Rijndael

The Galois Field is used in the mixColumns step of the Rijndael-Algorithm. Over $\operatorname{GF}(2^8)$ (irreducible polynomial: $x^8 + x^4 + x^3 + x + 1$), the first value of a matrix multiplication (all numbers are hex numbers) would…
user3608078
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How 2 rounds in AES achieve full diffusion?

I have read somewhere that 2 rounds is AES provide full diffusion. So I looked it up to find out what it exactly meant. In The Design of Rijndael page 41, section 3.5 and it states that: Two rounds of Rijndael provide 'full diffusion' in the…
Anton Paragas
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How were the AES key and block length subsets of Rijndael selected?

My intuition tells me it's a trade off between speed and security, but how did the standardisation process select these three seemingly arbitrary key lengths (namely, AES-128, AES-192, AES-256).
user1449
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AES key expansion: 256bit key

In AES algorithm, in the key schedule, Why does the expansion of a 256 bit key need an extra application of the S-box, unlike the expansion of 128 bit and 192 bit keys ? (The obvious answer would be "because it is more secure" ... but why ? And if…
tech
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Advantage of AES(Rijndael) over Twofish and Serpent

I'm trying to figure out a suitable encryption technique and after reading a bit, I figured the current AES 128-bit encryption is suitable for what I'm trying to do. However, this is more due to the wide-range use of AES than any other factor. So I…
GamingX
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How do Käsper and Schwabe's Bitsliced AES Mixcolumns work?

The only way I see it possible to do the matrix-multiplication in the MixColumns operation of AES is by shifting the bits in the multiplied number, and then reduce with the polynomial if needed. This can be done in constant time for a bitsliced…
oPolo
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