Linked Questions
16 questions linked to/from What are the requirements of a key schedule?
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What are recommended, general strategies to start block-cipher design and/or analysis?
I (and many others for that matter) have always been fascinated by the inner workings of the modern building block of cryptography: block ciphers.
Now, the resources on the "black art" of ...
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Why expand keys? Why not rather generate a longer key?
AES-128 takes a 128-bit key (four 32-bit words), and expands it to a 352-bit key schedule (11 words). Speck48/72 takes a 72-bit key (three 24-bit words), and expands it to a 528-bit key schedule (22 ...
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What are the qualities of a good block cipher? Beginner, Intermediate, Advanced, Expert [closed]
Notice: I'm doing this to learn. I know not to use a homemade cipher for anything that requires security. I also have heard before I'm not supposed to be trying this, but I learn best through trying ...
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Security importance of Key Schedule in Block Cipher
For example block cipher AES-128, Key size is 128bit and it is used to make a 10 round key which is total 320bit.
Question 1. If i use another Key schedule algorithm in AES, then security decreased ...
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Is the AES Key Schedule weak?
After reading this paper entitled Key Recovery Attacks of Practical Complexity on AES Variants With Up To 10 Rounds, I was left wondering why AES's key schedule is invertible.
In the paper, the ...
user1449
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Perfect secrecy with XOR & SHIFT?
I have read that XOR provides perfect secrecy, when the key is perfectly random. However it's technically hard to generate truly random numbers, especially on computers, so that is why people use AES, ...
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A block cipher whose key changes after each block
I have been reading about various block cipher modes of operation, and all of them seem to treat the block cipher (including it's key and key schedule) as a sort of immutable black box.
I would like ...
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Security of key schedule that only XORs a key with constants
Suppose that:
$MK \in \{0, 1\}^{n}$ and the main key of a block cipher.
$RK_{r} \in \{0, 1\}^{n}$ and is the $r$th round key.
$RC_{r} \in \{0, 1\}^{n}$ and is the $r$th round constant.
$RK_{r} = MK \...
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1
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Does the key schedule function need to be a one-way function?
For some key schedule $e_n(e_{n-1}(k))$ (where $e_{n-1}(k)$ is the result of the previous round) , does $e$ need to be a one-way function?
In the case of DES or Rijndael the key schedule doesn't ...
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Camellia Key Schedule
Camellia is widely used, an international standard now. Its key schedule seems to be too simple compared to other famous ciphers like Twofish and CAST-256. What are the prerequisites for the key ...
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Replacing a block cipher's key schedule with a stream cipher
Take Rijndael (AES) of block size 128 and reformulate it with a tweakable number of rounds and no key schedule.
Suppose we obtain:
Rijndael128(r, k)
where r is ...
user10653
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vote
1
answer
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How should the key schedule be designed for this general block cipher?
After looking at the Wikipedia page for the Fiestel cipher, I thought about making a variation of it that is very general.
I basically followed the diagram on Wikipedia in order to structure the ...
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AES key schedule. Does it use a KDF to generate the round keys?
So for each round in AES a different key is used, and as I saw the keys are created form a master key.
My question is how these round keys are generated.
Are they created via a Key Derivation ...
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DES security if used a SHA3 function instead of Normal DES function?
I was practicing some python programming and I decided to implement a simple DES encryption function, so i decided to take some shortcuts so instead of DES expansion boxes and s-Boxes i just used a ...
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Desirable Property of Block Sub-Keys
What is the more desirable for a block cipher's sub-keys ?
Given two blocks ciphers, letting all other properties be equal (they have the same strength), the only difference between them is that:
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