Questions tagged [symmetric]
Symmetric cryptosystems assume two communicating entities share a pre-established secret key.
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Is plaintext and ciphertext absolutely one-to-one in symmetric encryption algorithms? [closed]
Known conditions:
The block size of this algorithm is 16 bytes.
If there are multiple encryption modes, then it is limited to ECB mode.
Always use only one immutable key.
Since only ECB encryption ...
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The security of cyclic affine key schedules
Suppose that $k$ is the key for a block cipher. I am interested in the security of key schedules of the form $(k_0,\dots,k_n)$ where $k=k_0$ and $k_{j+1}=A_jk_j+b_j$ where each $A_j$ is some constant ...
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Can the requirement to increase rounds with key size be bypassed?
When taking AES for example, the number of rounds increases as the key size increases.
This is done in order to adequately diffuse key bits into the state of the cipher.
Suppose you replace the AES ...
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How to evaluate the minimum complexity of the key recovery when the success probability p is given？
Since the practical security of a symmetric-key primitive is determined by evaluating its resistance against an almost exhaustive list of known cryptanalytic techniques.
My problem is that could we ...
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Does something like Symmetric reencryption exist?
I'm an amateur so bear with me.
I was thinking about an E2E solution for data-at-rest proxy scenarios (like cloud storage provider) that allows you to issue and revoke users via symmetric keys.
I'm ...
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Why does symmetric encryption not provide authentication and integrity? Is it only this type of encryption or cryptology in general have this issue?
Studying for Cryptology and came across a presentation regarding on "Integrity vs Authenticity" where the discussion briefly mentions how Encryption "does not provide integrity or ...
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Why KeePassXC is deriving (stretching) the key again before saving changes to the database?
KeePassXC supports Argon2, which is great for security. However, there's a quirk that's been bothering me. Every time I save modifications to the database, it seems to stretch (derive) the key again, ...
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For Symmetric Cryptography, why is it considered more important to safeguard a key than the function/algorithm for encrypting/decrypting a message?
As stated for the question above here's an analogy:
You are a robber looking for a house to rob with two different scenarios that might occur.
1. You have a key that you know belongs to a house and ...
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Does ISAAC really guarantee a cycle length of at least 2**40?
I just noticed that the FSE 1996 conference paper which defines ISAAC mentions a counter variable cc.
This variable is said to be the reason why ISAAC has a ...
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Is ISAAC+ actually an improvement over ISAAC?
I just tried to implement ISAAC from scratch, using the Jean-Philippe Aumasson paper from 2007 as a reference.
This paper gives a definition of the original ISAAC algorithm as well as the improved ...
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How secure is a file encrypted with GnuPG, a strong passphrase, and the symmetric option?
Suppose I encrypt a file, of, say, 10 MB, with a secure, suitable passphrase, and the command:
gpg --symmetric my_file.txt
What level of expertise and hardware ...
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symmetric key generation - random number vs pbkdf2
I am working on improving my grasp on applied cryptography. Following question is just for learning/understanding purposes..
Lets say I want to generate a 16 byte key that I want to use for some ...
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Does any encryption/decryption algorithm supports linear decomposition?
I am not sure whether "linear decomposition" is appropriate to summary my question: We know that the traditional symmetric encryption/decryption algorithm (like AES, TDES) can be written as:
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Safe implicit value validation: $H_k(k \oplus m) \sim H_k(m)$?
$H_k$ is a cryptographic hash function that's keyed using a section of key material $k$ (for whatever definition of "keyed" that's appropriate for the given hash function $H$).
Are the ...
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Can I predict CryptGenRandom on my own device?
I have a Windows 10 laptop with an algorithm that creates a random number using the PRNG CryptGenRandom. According to Wikipedia:
Because CryptGenRandom is the de facto standard CSPRNG in Win32 ...
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