All Questions
19
questions
1
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46
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How Helpful is NXP's LRP Encryption Protocol vs AES for short keys?
NXP has a custom (I think) encryption protocol known as "Leakage-Resistant Primitive", or LRP, built on top of AES. I think the goal of this is to basically "expand" the length of ...
- 111
0
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0
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51
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Securing symmetric ciphers with 56-bit keys
Under the Wassenaar Arrangement and applicable export control law, symmetric cryptography of an (effective) key size of 56 bits or less is (generally) exempted from export control. I am forced to work ...
- 21
1
vote
1
answer
117
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What kind of symmetric key ciphers are secure thanks to the intrinsic cryptographic method instead of making the key length very long and secure?
For example, Threefish has a key length of 1024 and a very long number of rounds (80). but, I have not heard much about Threefish-1024 being particularly secure, so what symmetric key ciphers are ...
- 147
2
votes
1
answer
435
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Bruteforcing a symmetric cipher [duplicate]
I don't understand how we could bruteforce a symmetric cipher.
Let's take AES with a key size of $128$ as an example. It means that there are $2^{128}$ possible keys, and as many ways to decrypt a ...
- 241
0
votes
1
answer
256
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Calculating symmetric key bit strength
16 byte key where each byte is in range 0-255, generated using cryptograhic PRNG will be believed to have 128 bit strength.
What would be a bit strength of a key generated using same quality PRNG, ...
user80928
3
votes
0
answers
171
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Key strength comparison: symmetric key vs RSA/DH key
I came across different reputable sources quoting different equivalent symmetric key strengths for RSA/DH keys. This NIST paper (page 67) states the following offer corresponding security strenghts (...
user80928
0
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0
answers
71
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Symmetric algorithm effective key length
If we have a symmetric algorithm with key length $m$ bit, and we do a 5 time encryption with it.
How much will it be its effective key length.
- 135
7
votes
1
answer
16k
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How Secure is gpg Command Using Symmetric AES-256 From Being Cracked
How secure is any data encrypted using the following command:
gpg -o *encrypted_output_file_name* --symmetric --cipher-algo AES256 *file_to_be_encrypted*
Can ...
- 171
1
vote
1
answer
88
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Which symmetric algorithm should I use for storing files in untrusted servers?
I have gigabites of files, which I have to backup. I have some servers for storing this files. But these servers are untrusted. So I need to encrypt files, then backup files. When my PC breaks down, ...
- 111
3
votes
2
answers
672
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Should text be hashed before being used as an encryption key?
Let's say I have an API that provides an encryption wrapper around another API. I give the consuming programmer the option of either passing a string or byte array as an encryption key.
The byte ...
- 469
4
votes
0
answers
246
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Safely using ciphers that take small key sizes
Is it feasible to use triple encryption for block ciphers with the maximum keysize being the only significant security issue? I mean $C = E_{k_1}(E_{k_2}(E_{k_3}(P)))$ and $P = D_{k_1}(D_{k_2}(D_{k_3}(...
- 15.4k
2
votes
2
answers
191
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Existence of 99% successful unbounded adversary against randomized secret key encryption scheme with short keys
It can be shown that if $E$ is a deterministic encryption with key of length $n$ and messages of length
$l\geq n + 10$ then there exist two messages $m_0$, $m_1$ and a strategy for Eve so that
given ...
- 101
1
vote
2
answers
2k
views
NIST HMAC Test vectors
I am searching test vectors of the HMAC-SHA256 primitive to verify the correctness of an implementation.
Without hesitation I go on the NIST website to see what they offer.
While reading the ...
- 2,858
0
votes
1
answer
3k
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Probability of guessing random 128-bit AES key
Consider the following five events:
Correctly guessing a random 128-bit AES key on the first try
Winning a lottery with 1 million contestants
Winning a lottery with 1 million contestants 5 times in a ...
- 23
1
vote
1
answer
84
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Can one deduce the symmetric key size used to encrypt a given a piece of ciphertext?
Assume an attacker captures a piece of ciphertext encrypted with a symmetric key.
He knows all the details of the algorithm used to encrypt except for the size of the key used in this case.
Can he ...
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