instruction stringlengths 32 27.2k |
|---|
I want to make an ecryption algorithm that is secure in, well, really many ways, which is hard I see, so I came up with some ideas of how to implement it using some primitives that I know and I actually discovered some online that resemble it, but I thought it's time to consult the forum about it.
Firstly I should defi... |
I am working on randomness testing of block cipher. I have gone through the NIST two papers of randomness testing of AES candidate algorithm, links are given below
https://csrc.nist.gov/csrc/media/publications/nistir/6390/final/documents/ir6390.pdf
https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=151216
NIST use... |
I know that PBKDF2 hashes the password a number of times, the result being a key. Can an attacker find the key if they don't know the password, but know the value of the hash of the password?
|
As explained in their example here, Microsoft Seal uses a special modulus that is used for all key material like relinearization key. I wanted to ask why special modulus is used?
|
It is said that Dual EC DRBG has a backdoor given the values of the curve. Hence some people do not trust it.
With that in mind, some people also distrust NIST P-256 Curve. Why? Is it purely because it’s from NIST? Is it the same curve as Dual EC DRBG? Or is it merely by association? Does P-256 use Dual EC DRBG? Or can... |
I am looking for a textbook or published paper that provides specific information on how to configure an ECC. I came across it several years ago and now cannot find it. Does anyone know the source? Specifically, it talked about how to define number ranges inside the ECC with varying equations.
|
Searches have returned absolutely no results on this question. With that in mind, I assume the answer is either painfully obvious ('of course quantum computers get no advantage when it comes to storing data') or the question has just not been studied. Intuitively it makes sense the quantum algorithms would gain no adva... |
Scenario: have an entity A that cannot hold any secret keys. A concrete example would be: an application that needs to be open sourced and cannot be modified. In order to send any signed messages, it uses a proxy signer P. P holds the secret key and signs on behalf of A.
The issue: how does the message recipient verify... |
I was in an interesting discussion with Jon Skeet on StackOverflow. He indicated that hashes are irreversible, but he extended this to non-cryptographic hashes. A hash function has a specific output size while the function can handle any sized messages. So if you argue from that point of view, a hash is always irrevers... |
I was comparing classical schemes with post-quantum schemes. Therefore I was interested in the round three candidates of the NIST standardization process. So far I know, that those post-quantum schemes need a much bigger key-, signature- and ciphertext sizes. Regarding performance, I concluded that the difference is no... |
In RSA we compute e (encryption key) and d (decryption key) $\bmod phi(n)$ and not $\bmod n$, so how come when we get the keys and encrypt and decrypt we use $\bmod n$ not $\bmod phi(n)$ using the following rules:
Encryption: $C =(m^e) \bmod n$
Decryption: $m = C^d = (m^e)^d \bmod n = m^{e.d} \bmod n = m^1 \bmod n = m... |
In DSA, we compute the signature $(r,s)$ on $m$ by sampling $k\in\{1,...,q-1\}$ and then computing
$r := g^k \bmod p$
$s := k^{-1}*(m+x*r) \bmod q$
During verification, we compute $v:=g^{m*s^{-1}}*y^{r*s^{-1}}\bmod p$ and then check $r=v \bmod q$.
Question: Would it be fine to leave $k^{-1}$ out from the computation of... |
I'm developing a way to deterministically generate private keys for arbitrary elliptic curves based on some user-input (a brain-wallet). Currently, I'm using the Scrypt password hashing algorithm with robust difficulty parameters to hash a number of input parameters into a key.
The output of Scrypt should be uniformly ... |
How to make a proof of the correctness of the RSA encryption and decryption formula for $GCD(m_i,n)=1$ and $GCD(m_i,n) \neq1$ where encryption is defined as $c_i = m_{i}^e$ mod n and decryption $m_i = c_{i}^d$ mod n.
So thanks @poncho for giving tips, I wrote a following proof:
Recall that the integers $e > 0$ and $k ... |
I'm going to use the Simon Cipher as an example, but I want to frame the question to be more general. Why would the same cipher structure have a different optimal attack for different bit widths? I would think that structure would be what dictates the attack and not the bit width. SIMON32/64 and SIMON128/256 are vir... |
For a project I'm working on, I need to implement ECDSA over the NIST P-384 curve (AKA secp384r1). For what it's worth, the choice of curve is beyond my control in this particular case.
While I already have a working implementation, and this is (so far) just a low-stakes pet project, I was wondering how I could take ca... |
I was looking for an example of protocol to verify user's identity using Diffie Hellman which works like this:
client sends: $g^x$, ID-Number
server responds with: $g^y$, $E_H_{pwd} challenge$
client responds with: challenge
I understand that g^x, g^y are Diffie Hellman keys, plus it's given that H is a hash function... |
In some contexts (HKDF (RFC-5869 sec 2.2) and Bitcoin's BIP32 (master key generation)), I have seen the key and the data swapped for HMAC. E.g., let HMAC be a function $h:\{0,1\}^c \times \{0,1\}^b \to \{0,1\}^c$ (usual notation) defined for a key $k$ and data $m$ as $h(k, m)$. Well, some people let $k$ be a fixed publ... |
From a very basic introduction text to elliptic curve cryptography point arithmetic is derived from "standard analysis": The (negative) sum of $P_1$ and $P_2$ is defined as the Point $P_3$, which is on the line connecting $P_1$ and $P_2$:
From that it is derived
In real numbers I would understand that completely. But... |
I have been searching for many days about the time complexity of O(n) for AES (preferably CBC mode). Moreover, I am searching for formal documents like papers/books/standards. I found this paper: https://ieeexplore.ieee.org/document/5945606 that says O(1)... I can't believe that! And this: https://link.springer.com/cha... |
In RFC 5869, the definition of HKDF-Expand is given as follows, with the terminating counter value ranging from 1 to (presumably) 255:
The output OKM is calculated as follows:
N = ceil(L/HashLen)
T = T(1) | T(2) | T(3) | ... | T(N)
OKM = first L octets of T
where:
T(0) = empty string (zero length)
T... |
In the security game between the challenger and the adversary for the security definition of public key encryption, the challenger creates and gives the public key pk to the adversary. The adversary chooses two messages of equal length $m_0$ and $m_1$ and asks the challenger to encode these. Finally, the adversary has ... |
For LWE/RLWE, it's difficult to find $s$ from $\left(A, b = As + e\right)$. But if the partial information of $s$ is leakaged, such as partial $s$ or parity of $s$, how easy would it become to solve LWE?
I don't know much about the algorithm for attacking LWE/RLWE, if there is some relevant literature recommended that ... |
It is known that Shamir's secret sharing works over any finite field but I don't get it why binary extension fields are preferred?
|
I'm trying to implement two party computation for ECDSA signing using Paillier cryptosystem.
But my problem is that the order of Paillier is different from the order of the curve (secp256k1 in my case) so when I multiply two scalars in Paillier and then I decrypt them they are in a different order than the rest of the ... |
I found a construction for MDS matrix (algorithm 4 of https://eprint.iacr.org/2020/1143) for a hash function that compresses elements in a prime field $F_p$
If the hash has a rate and capacity $(r,c)$ and $m = r+c$. It proceeds as
Identify a primitive root of unity $g$ in $F_p$.
Write a Vandermonde Matrix $V[i,j] = g^... |
Im working on TLS1.2 on cipher suite ECDHE_ECDSA_AES_128_CBC_SHA256. Im currently at the stage of client encrypted message where I always got error on wireshark from the server saying that Fatal, Description : Handshake Failure. So from what I have done my research, the contain for this client finish message suppose to... |
Usually RSA uses an encryption exponent $e$ with $\gcd(e,\phi(N))=1$.
This question shows why that need to be the case: For $\ne1$ there might exist no decryption exponent $d$ because other $m'\ne m$ can exists with $m^e \equiv (m')^e \bmod N$.
However if we produce our $m$ like:
$$m = m_0^{e} \mod N$$
or more general
... |
There has been a lot of discussion about whitebox cryptography in recent years. However, I haven't found any signs of real world applications using it.
Are there any real world IT solutions depending on whitebox cryptography as of 2022?
Is any kind of whitebox cryptography considered secure by any authority (NIST etc.... |
I'm looking for the ability to create a SINGLE CONSTANT shared secret amongst two or more users (a group) AND if a new user is added to such a secured group the new user should also be able to learn the already known and shared secret without the existing users needing to resend any new data or changing the common secr... |
I'm trying to do ECDSA signing, and I need to compute
$$\left(k^{-1} \bmod n \cdot (m + d\cdot r) \bmod n\right) \bmod n$$
I'm able to do the inverse function and multiplication in Montgomery form, but how should I add $m$? Does the arithmetic play well if I just converted $m$ to Montgomery form? Alternatively, I could... |
I was searching for a random seed to use with a pseudo-random number generator (not trying to encrypt anything). I went to the following web sites:
https://www.fourmilab.ch/hotbits/secure_generate.html
https://www.random.org/
It appears that Random.org has a solid history and is not experiencing problems with DDoS atta... |
While Public exponent is an even number which means Can't get the d in normal way since gcd(e, phi) won't be 1, and in this case only used one prime number for N (multiple uses for one prime number)
What is the idea of getting the m,could p = 3 mod 4 be helpful?
Thank you for any idea.
|
I'm trying to answer without success questions (ii - iv)
Any hint will be appreciated :)
|
If person A generated a hash (e.g sha256) of a file and then signed the hash using a private key.
Given person B only has the public key, file, signature and the hash, would verifying the signature using the public key be sufficient to prove person A signed the actual file?
What hashes and algorithms are best suited to... |
I can't seem to wrap my head around these encryption methods. I can't find a brief description for any of them.
Hash then encrypt
MAC then encrypt
Encrypt and MAC
Encrypt then MAC
|
I know that it wouldn't be possible to use the extended Euclidean algorithm, since it would require the ability to divide a public key and calculate the remainder. I was wondering if there were any other ways of calculating the modular multiplicative inverse of a point on an elliptic curve (like secp256k1)? Or perhaps ... |
I want to calculate the entropy of a specific cryptosystem such as the Caesar cipher or Vernam cryptosystem etc but I don't quite understand how to do so. Any help?
|
Recently I have few experiences with Questions in RSA which e is 2^n instead of 2^n+1, and that leads to gcd(e, phi) is not equal to 1... Won't this make the private key impossible to get? Is the Rabin cryptosystem the only way out?
|
Is there any known/standard encoding or cipher method that uses a 64-character alphabet from byte 30 (ASCII 0) to byte 6F (ASCII o)?
I'm trying to reverse-engineer a file format, and I have good idea of what some of the contents of the files should contain, but I'm not seeing any obvious patterns in the data that corre... |
Block ciphers that are NOT LIGHTWEIGHT use relatively complex key scheduling algorithms to enhance their security and thwart some of the known cryptographic attacks. In such ciphers round constants are also added for removing symmetries in the structure (if these exist) but the selection criteria for the round constant... |
The NIST is currently trying to select new standards for post-quantum cryptography.
The two main categories for the candidates are "Public-key Encryption and Key-establishment Algorithms" and "Digital Signature Algorithms".
The signature algorithms are based on public-key encryption algorithms. Thus, why to separate th... |
I need to know the key exchange of the DHE-DSS cipher suites, will it be the same as mentioned in DHE-RSA?
|
In order to try to simplify or alternatively express cryptographic functions I wonder if the modulo function can be alternatively expressed. Could for example a Fourier series of a sawtooth wave or its discretization be useful? What would that look like for a given range and precision?
|
From this Wiki page: given a Goppa code $\Gamma(g, L)$ and a binary word $v=(v_0,...,v_{n-1})$, its syndrome is defined as $$s(x)=\sum_{i=0}^{n-1}\frac{v_i}{x-L_i} \mod g(x).$$
To do error correction, Patterson's algorithm goes as follows:
Calculate $$v(x)=\sqrt{s(x)^{-1}-x}\mod g(x)$$ (this assumes that $s(x)\ne 0$,... |
please verify or explain how to do this properly.
I'm letting a user create keys from the client through a secure server.
I ask the user for a password on the client, then send the hashed password to the server. The server generates fresh keys and encrypts them with the password hash + the generated verification key. T... |
Related Problem
Standard Addition-Subtraction Chain (ASC) for an integer $k$ defines the order of addition/subtraction (doubling) operations so that $k$ is finally reached, starting with $1$.
This is particularly useful in ECC to calculate $k\cdot P$ via EC point additions/subtractions & doublings.
The goal is to find ... |
Let's suppose I insert these two 4-byte words (32-bits) in a feistel S-box with 1024-bytes of size (256*32-bits), (like Blowfish does):
blah bleh
What kind of attacks could possible be made to discover the words faster than brute-forcing the entire S-box (if they exist)?
Does inserting words/bytes in feistel S-boxes ha... |
I am trying to develop a simple protocol for two users to verify (with respect to a trusted central authority) that they have (intentionally) met/communicated with each other.
My idea was this: Users own a (public, secret) key pair of any common asymmetric system, such as RSA. Their public key also servers as their ide... |
Let $E:\{0,1\}^{128}\times\{0,1\}^{128}\to\{0,1\}^{128}$ be the AES encryption and $R\gets\{0,1\}^{128}$ uniform random bitstring.
Would $E'(K,P):=R\mathbin\|E(K,P)\mathbin\|E(K,R\oplus P)$ be IND-CPA?
I am not sure about my opinion, but I think this would not be IND-CPA since $E$ is determistic and $R$ is used twice i... |
Suppose some original material (say a text message, text.txt) is encrypted multiple times, (say using ChaCha20) each time with a different key.
Suppose the output of this process is a binary (output.bin).
Suppose some third party is attempting to crack the file output.bin.
Suppose this third party succeeds in cracking ... |
Usually the requirements for passwords are that they should be salted and use a high number of rounds.
My understanding is:
Salting a password is only used to prevent rainbow attacks
Using a high number of rounds is only used to prevent brute-forcing short passwords
But if a password is computer generated and only us... |
Imagine a protocol where all one time pad messages are of a fixed length. And they're textual only, à la Truths/Tweets. So a short message would be padded with spaces (ASCII 32) up to the protocol's fixed length, and then transmitted. It would also be appended with a properly formed RFC 2104 HMAC which itself is encryp... |
Identity Based Encryption is an asymmetric encryption scheme such that encryption uses the receiver's identity as the public key. Such a identity can be receiver's email address or some other string that stands for receiver's identity. In this way, before encryption we need not verify the receiver's public key like tra... |
Is it possible for a client to send a blinded password to a server, so that the server does key derivation+stretching on that blinded value, but the key can then be unblinded by the client?
Clarifications
I'm using "blinded" the way it is used in an "oblivious pseudorandom function" (OPRF) like Ristretto255.
Usually I ... |
Suppose an encrypion scheme uses a random string to encrypt and decrypt, which is publicly available, such as an IV or nonce. In all the cases I am aware of, the existence of say an IV is not "assumed": it is taken as fact that generating a 128 bit IV for example is easy and the existence of such a random IV is not th... |
I understand that, as stated here, CRC is not linear (with respect to XOR operator) in general, because it could be initialized with a non-zero value.
I was wondering how to prove linearity, when zero is used as the initial value for CRC. Basically, I'm trying to prove the following equation: (with ⊕ being the XOR oper... |
I am reading the Real-World Cryptography book and in the chapter on signatures it says:
The best way to understand how signatures work in cryptography is to understand
where they come from. For this reason, let’s take a moment to briefly introduce ZKPs
and then I’ll get back to signatures.
I find this hard to believe... |
Hello everyone on the forum,
I'd like to give you an idea of how the keys in RSA could be cracked.
I am a passionate amateur and I do not know if this idea makes sense, but I would like to present it.
I would like to start from the beginning to describe the idea in an understandable way.
We know what RSA numbers are ... |
As I understand, Frobenius Norm is supported under homomorphic encryption. (It’s HE compatible.) However, I cannot seem to find the corresponding function in palisade’s library and documentation. Or any other HE library.
If there’s such function, please tell me.
If not, why not? because it’s very expensive computation... |
I designed this pseudo-random function algorithm that takes a uint64 and returns a uint64. I'd like to know if it is any good and if so, if it is original? If not original, who came up with it first?
First you start with 65 constant random uint64s. Lets call them $P_0$ thru $P_{64}$
For an input uint64 X you XOR toge... |
What is reset indifferentiability? Why practical hash functions cannot satisfy reset indifferentiability. What are the implication of reset indifferentiability.
|
According to this page, Curve25519 and Ed25519 are not isomorphic, because the birational equivalence equation has singularities:
What does "birational equivalence" mean in a cryptographic context?
But... Curve25519 and Ed25519 are both cyclic groups, right? Both have order of $2^3 * (2^{252}+277423177773723535358519... |
I'm trying to implement own DSA signature check as per guide at this site page 20 in python.
kp = 0x8df2a494492276aa3d25759bb06869cbeac0d83afb8d0cf7cbb8324f0d7882e5d0762fc5b7210eafc2e9adac32ab7aac49693dfbf83724c2ec0736ee31c80291
kq = 0xc773218c737ec8ee993b4f2ded30f48edace915f
kg = 0x626d027839ea0a13413163a55b4cb500299d... |
Out of $N = s^3$ total points we pick a starting point $p$ and an end point $q$
with
$$p=(p_1, p_2)$$
$$q=(q_1,q_2)$$
$$p_1,q_1 \in [0,s)$$
$$p_2,q_2 \in [0,s^2)$$
We want to find a path in between them.
For doing so we have two kinds of progression:
A trivial one by just walking forward:
$$f((e_1,e_2)) = ((e_1+1 \bmo... |
I am trying to understand a request I reverse engineered which is sent to a Daly BMS over BLE.
Those requests change the 'sleep after' in seconds of the BMS:
For DDDD seconds: d2 06 00 8A DD DD 22 8A
For FFFF seconds: d2 06 00 8A FF FF BA 33
For EEEE seconds: d2 06 00 8A EE EE 76 6F
For FFFE seconds: d2 06 00 8A FF FE... |
I am working through Katz and Lindell, and Theorem 3.26 in the book proves that a construction based on a PRF is CPA-secure. The thrust of the scheme is that if $F_k$ is a PRF, with $k, m, r \in \{0, 1\}^n$ (key, message, random-string), then $c = (r, F_k(r) \oplus m)$.
The idea behind the proof is to first prove the ... |
Does HMAC take part in TLS/SSL? When the client and the server pass the TLS handshake and create a common SESSION key, do they also HMAC each message that is being sent out for the purpose of data integrity?
|
Suppose there are different users data for $n$ Smart meters. We encrypt all the individual data and then add them together. After decrypting the summation, how can we retrieve the original data? We are using pallier cryptography.
|
When I use the merkle proof example of libsnark, I find that it takes more time to calculate the merkle tree than to calculate the proof. As shown in the log below, it takes 0.04s to calculate a SHA256. When the depth of the tree is 20, it takes at least 3 hours to exac SHA256, but only 14s to exac proof. I notice that... |
Is RSA-signing a given challenge $x$ a zero-knowledge proof of holding the RSA private key, for the modern definition of zero-knowledge proof (which I don't know!)
Assume public and genuine RSA public key $(n,e)$, secret RSA private key $(n,e,d,p,q\ldots)$ with distinct secret primes $p$ and $q$, that the factorization... |
While reading about the Davies-Meyer mode (and other modes), I have got some doubts:
What can I use as the key to the encryption $E$? Since I am generating hash of a message (not MAC), then there should not be any secret key involved.
What is the initial hash value ($H_0$)? Can I take it as some public value (IV/nonce... |
Reading the wikipedia entry on asymmetric cryptography, will I be wrong to conclude that there are 3 main broad category of application for asymmetric cryptography? Mainly:
encryption
digital signatures
key exchanges
Or are there other category of applications for asymmetric cryptography that do not fall under these ... |
For every $a \in \{0,1\}^n$ define:
$$h_a : \{0,1\}^n\to \{0,1\}$$
$$ h_a(b)=\langle a,b \rangle$$
So $\{h_a\}_{a \in \{0,1\}^n}$ is known to be a universal hash function family.
This means that if we denote this family by $\mathbb{H}$, and the random uniform distribution over this family by $H$ then for any $k$-source... |
If the inputs for a garbled circuit are from multiple parties, can parties (not garbler, not evaluator) obtain the labels corresponding to its input from the garbler via oblivious transfer then send the labels to the evaluator? Will this have any security issue?
|
From what I understand, to reduce the time taken for public key generation, you can use nested trees in XMSS to form Multi-tree XMSS.
For an instantion of 2 layers, it seems that the leaf of each L tree (one of these nested trees) is an OTS public key. This means that the leaves of the top level tree sign the OTS keys ... |
I started wondering. RSA relies on prime factorisation being hard. So if a 2047-bit oracle machine existed that could instantly factor any 2047-bit number (and you can't look inside at how it works), would that in any way help in breaking 2048-bit RSA encryption?
My insticts says no, but I can't be sure.
|
Given a $N$-bit AES or similar block cipher with his $N$-bit key $k$.
We can encrypt a $N$-bit message $m$ to a $N$-bit cipher $c$ and decrypt it again.
$$E(m,k) = c$$
$$D(c,k) = m$$
An adversary does know $n_m$ bits of the message, $n_c$ bits of the cipher and different to most applications also the full key $k$.
He ... |
I was reading this challenge, which proposes to clone (or recover) the internal state of the MT19937 just by applying the inverse process to each output (624 consecutively words).
Mersenne Twister's FAQ also says:
Mersenne Twister is not cryptographically secure. (MT is based on a linear recursion. Any pseudorandom nu... |
Secure Equality Test is an important building block in Secure Multi-Party Computation (MPC) with respect to Secure Comparison, also known as Socialist millionaire problem.
A similar question was posted several years ago (Extending the Socialist millionaire problem to three parties), but it seems to be considered from Z... |
Can I safely use a signature as a private key for the purposes of encryption?
let sig = sign("email", "originalSecretKey");
encrypt(
"foobar@example.org",
"someNonce",
"theirPublicKey",
sig // <--- Use signature as new private key?
);
I'm looking for a way to "scope" the originalSecretKey. Let the user saf... |
I understand that in the non-interactive linear form (page 15 of Groth16: https://eprint.iacr.org/2016/260.pdf), given $A$ and $B$ in the proof $(A,B,C)$,
the simulator can compute the $C$ by:
$C =\frac{AB-\alpha\beta-D}{\delta} $ where $D = \sum^{l}_{i=0} {a_i(\beta u_i(x) + \alpha v_i(x) + w_i(x))} $.
However, I do... |
I am a Ph.D. student studying CS theory, I made this account for this question.
Recently, I seem to have obtained a proof of existence of a PRP (which is unconditional in the sense that it does not rely on unproven assumptions), but in order for it to work it does require a limitation of the running time of the adversa... |
I understand by the birthday problem, the algorithm will expect to take $\mathcal{O}(\sqrt{N})$ times to find a cycle. However, one of the steps involves computing the $\gcd(\mid x-y \mid, N)$, which, I assume, uses the euclidean algorithm, which is $\mathcal{O}(\log(N))$. So shouldn't it run in $\mathcal{O}(\sqrt(N)... |
Say, for an AES-GCM encryption, an attacker knows essentially everything except the key. This would include:
Plaintext
Ciphertext
IV
Algorithm (AES-GCM)
In this case, will the attacker gain any advantage towards learning the key?
The application: I am using Password-Based Encryption following PKCS #5 recommendations.... |
As a beginner in cryptography and zk-SNARKs, I am currently working through the paper "Why and How zk-SNARK Works".
There, I don't understand the last section at the bottom of page 15:
While in such protocol the prover’s agility is limited he still can
use any other means to forge a proof without actually using the
pr... |
MRT is a probabilistic test and even the deterministic version relies on the correctness of the Riemann hypothesis.
When the test fails and I use a non-prime number in e.g a public key encryption method: what is going to happen? Will my public key not work, will it be a little less secure or will it be completely insec... |
I'm having trouble making an implementation of Enigma Machine in VBA. My question is about implementing the rotors and their move.
To be more precise, I will show below the way that I code my Enigma Machine for the move of the rotors:
Example :
Rotor : I II III
Initial value A A A
Ring Rotor (set up rotors) : 1 1 1
... |
I’ve been implementing Hasty Pudding from its spec, but I can’t find a copy of the test data to validate my implementation against.
The directory of tests links to various files in ftp://ftp.cs.arizona.edu/xkernel/rcs/hpc/test/, but that server no longer talks FTP, and I haven’t been able to find the files anywhere els... |
I have defined the following commitment scheme and would like to prove that it is statistically hiding and computationally binding, but I'm not sure if my proof is accurate:
For $h$, a collision resistant hash function, I defined the following scheme:
$C(b, 1^n)$:
$r \leftarrow U_n$ // random uniform string of length $... |
As I know, the best attack on single or double Even-Mansour scheme is N/2, being N the key size (or size of one of the two keys used).
I know that encrypting two times using this scheme is susceptible to Meet-in-the middle attacks, but if encrypting three or more times, what security in bit I will get for each layer ad... |
I have been searching for resources on the internet about the efficiency of Encrypt then MAC, MAC then encrypt, MAC and encrypt, and hash then encrypt and I have come up short with all of them. Most sources will give what they will protect against but none will tell me what is more efficient in time and resource wise.
|
Given that CBC mode has a padding oracle attack, would disabling the padding integrity check be a good way of overcoming the vulnerability (this may result in frustration among existing users with regard to troubleshooting initial vector mismatches, but this will at least not render the mode itself vulnerable)?
|
In my database, I have a PBKDF2 hash + salt for every user. My objective is for the user to be able to log in without stating the user's password (in case somebody is logging the network traffic somehow).
I was wondering if the following scheme is secure, or if there are any fallacies.
Client starts the login process ... |
Encrypting values with AES we only need about $2^{64}$ trials until we finding an already used value (some collision). This can be done these days with easy.
To make this harder can we combine two AES to a block cipher $BC_{192}$ with $192$bit in- and output?
E.g.
Given $AES_1$ with $k_1$ and $AES_2$ with key $k_2$ (bo... |
With the term GPU programming, I'm referring to highly parallelizable computing in general.
Lastly, I have built a bit of a background in cryptography. So I have started to wonder if/where GPU programming is applicable for cryptographic use. I am thinking that in most use cases it will offer little to no advantage beca... |
This should be pretty simple question I presume. So let's say I have an 8x8 S-Box. I can easily treat it as 8 different boolean functions for each of the 8 input bits. Is the non-linearity the lowest linearity of each boolean function? Or is there something else that needs to considered with an S-Box? If it is differen... |
Is OK to derive a key using HKDF (Extract & expand) with a shorter size than the digest size of the configured hash function? In that case the result is computed (on the expand part) by truncating HMAC(PRK, "" | info | 0x01) .
If it is not OK, then I am thinking on using a hash function that has a shorter size in order... |
I'm trying to implement impossible differential cryptanalysis on IDEA cipher based on the Miss in the middle attack on IDEA and Khufu paper.
I'm trying to implement the attack on 3.5-Round IDEA and I stummpled with the initial pair generation step because they suggest generating $2^{32}$ pairs, which would normally be ... |
I want to identify hash algorithms without names (like sha256, ).
Is there a problem in make sha256('') and use the output like the id?
An empty string is really an empty input or this input is no really unique?
Thanks!
|
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.