instruction stringlengths 32 27.2k |
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As for the PQC algorithm Saber.PKE based on M-LWR, I wonder whether it supports homomorphic addition operation. According to my related work, the error of this algorithm can be written as $e_S = ||s^{\prime T}e-e^{\prime T}s +e_r||$, this fomula satisfies$e_S \mod p < p/4$. By parameters selecting, whether we could con... |
Is following approach secure?
Planning on using implementation to XOR two passphrases before feeding result to Argon2.
const xor = (a: string, b: string) => {
if (a.length > b.length) {
b = `${b}${b.substring(0, a.length - b.length)}`
} else if (b.length > a.length) {
a = `${a}${a.substring(0, b.length - a.... |
I encountered the following scenario in development of a system.
A user wants to perform an operation on one of $n$ days. An adversary can observe a sequence of integers $X_1, \cdots, X_n$. If the user performs the operation on day $i$, then $X_i$ will be sampled according to distribution $Q$, while all $X_j(j \neq i)$... |
I'm looking for a Additive Homomorphic Encryption scheme which can allow a ciphertext of size smaller than 128 bit.
I started studying this topic very recently so I don't have much knowledge, but I checked on Paillier and RSA and found out for 2048-bit RSA the ciphertext size is 2048 bit and for equivalent Paillier sch... |
I have been looking at the Galois/Counter Mode (GCM) for stream encryption. I understand the idea that it's a stream cipher and so it can be encrypted one bit at a time by XORing with the key stream and how this is better than something like CBC because you can start anywhere in the middle of the stream without calcula... |
A prover has a secret exponent $x$, two public bases $g$ and $h$, and a public RSA modulus $N$ of which no party knows the totient/factors. All inputs other than $N$ are coprime with $N$ with overwhelming probability. She publishes $a = g^x\bmod N$ and $b = h^x\bmod N$, but she needs an NIZK that she used the same expo... |
How to determine if an elliptic point $kG$ is negative? Is $k<0?$
By example, for $k=1234$, the coordinate of the point $1234G$ using secp256k1 =
$X= 102884003323827292915668239759940053105992008087520207150474896054185180420338$
$Y= 49384988101491619794462775601349526588349137780292274540231125201115197157452$
Note: $... |
As an example, let's take a simple situation where AES-256-CBC with IV + MAC is used to encrypt a given plainText to offer both authentication and prevent identical cipherTexts.
iv.mac1.cipherText(plainText)
The keys are derived using HMAC for simplicty (alternatively could be HKDF)
masterkey = [32 random bytes];
encr... |
As an example, let's take a simple situation where AES-256-CBC with IV + MAC is used to encrypt a given plainText and offer authentication.
iv.mac1.cipherText(plainText)
The keys are derived using HMAC for simplicity (alternatively could be HKDF)
masterkey = [32 random bytes];
encryptionKey = hmac_sha256(masterkey,'en... |
I have read/write disk images encrypted with 128 AES using Mac's disk utility. If I snapshot the encrypted disk images daily (sometimes with changes other times without), and an attacker has access to these snapshots, will they be able to gain any parts of the plaintext? Will they be able to gain any metadata about the... |
It's been a while since I know about cryptography, and always end up seing diagrams like this.
However I have never been able to understang their meaning. I hope someone can explain in detail. Thank you in advance
|
For data integrity, specifically for small blocks of data, rather than using a SHA-256 hash, or simply truncating a SHA-512 hash, I am playing with the following idea:
function saferHash(data) {
let hash1Entropy = 42; // sha512:42
let hash2Entropy = 4; // 4B extra possible protected outcomes in case of highly ... |
Why most of Lattice based scheme use Montgomery Multiplication algorithm?
|
I'm reading the paper Extending OT. In the extending OT protocol, the sender using $H(j, \textbf{q}_j)$ as the mask, why not use $H(\textbf{q}_j)$ directly?
|
I noticed some new quantum cryptography algorithms are being developed.
I know very little about quantum computing but my understanding is that it will just be a much more powerful computer and therefore all the current key sizes that we use for cryptography will be rendered vulnerable to brute force attacks. Maybe the... |
I am trying1 to build a Proof Of Concept of a e-voting scheme on a blockchain. Before the elaboration, the question:
On a public e-voting, how do I keep the votes from being disclosed prematurely without a trustee?
The project works the following way:
Noone trusts noone4, so no trustees at all.
A "blockchain" here is ... |
I want to evaluation following functionality:
Parties have secret shares of private input [a] and public input b, they want to measure if
a>b, additionally only one party should learn the output
I know this could be directly done with millionaire problem solutions such as:
CrypTFlow2: Practical 2-Party Secure Inferen... |
Since the maximum authentication tag (MAC) size of AES-256-GCM is 16 bytes,
And given that in one implementation, that breaking the MAC would break the security (ex. when a boolean 'decrypted' is used to either deny or allow access),
Would using an additional MAC within the cipherText be a good idea or is this over-eng... |
Suppose I have a dumb password checking function:
def dumb_checker(password):
return password == "my_secret_key_that_should_not_be_revealed"
One can hide a password by hashing it as follows:
def obfuscated_checker(password):
return hash(password) == PRECOMPUTED_HASH_OF_MY_SECRET_KEY
which means that the indis... |
I was wondering how "IPS" systems process and react to the AES encrypted data than the DES
|
If you alter the SPHINCS+ signature scheme such that the number of signatures it can sign is the same as the number of hashes the hashing algorithm can output such that for example if you have a 2^256 hash SPHINCS+ would be altered to be able to sign 2^256 messages.
Would you then be able to remove any requirement for ... |
I am planning to use AES-GCM or AES-CTR for encryption. However, I have read from several sources that the IVs must be unique for every piece of information encrypted. I have a doubt though, what if I choose different IVs for the two encrypt calls, but the counter addition makes the IV+counter value the same for some o... |
Trying to figure out how the scheme works I came across the last paragraph of the page. As stated, for any possible additional factor we multiply by the specified power v of the element g. How did this "possible factor" showed up? Even so, why multiplying with the specified power v of g solves the appearance of such f... |
For what I know from the RSA algorithm, the receiver of an encrpyted message needs the Euler totient to generate its private decryption key. If the sender has chosen two primes p and q, then the Euler totient could be $(p-1)*(q-1)$ which is a value needed for the receiver. In this case, how the Euler totient is shared,... |
I’m new to development using web3 technologies and I have a use case where I want to store private data about the user in the public blockchain Polygon.
This data should be recorded to be tamper proof and indisputable, however I also want to protect users privacy. This is why I came up with an hybrid solution I will di... |
Do there exist information theoretic secure public key crypto-systems? Are they useful in any way, or are they just mathematical curiosities?
|
I was learning about bitcoin cryptography and seen some strange bitcoin public addresses like this
1Lets1xxxx1use1xxxxxxxxxxxy2EaMkJ
1fuLL1xxxx1power1xxxxxxxxxxzatvCK
1of1xxxxx1anonymity1xxxxxxxz9JzFN
how someone can derive this kind of addresses from private key? and if it is possible somehow does it gives chance to... |
What is the signature size of Natasha Otomoski haircomb? What is the number of invocations of the underlying one way hash function for key generation, signature, and verification?
How does it compare to the recently standardized variant SPHINICS+?
|
I've been in my PhD program for a few months, and every time I try to understand the simulation and UC proof-paradigms I get so confused.
I feel like what I really need is an easy set of (guided) problems and examples that I can play around with and try to prove, starting with non-composable simulation and then moving ... |
I am a developer with very little experience on the crypto part,
and I'm looking for a secure solution (OTP Like) for identifying between client (browser) and server.
this is what i need:
Web Page at 10.00 AM generate a randomly id based on a secret key
User A
10.00 AM 258e461ba8b7b66a02cf17dfe60f465c103c742e570f492a31... |
The use-case is as follows:
There is a signer, call it $S_A$ that have a claim or document $D_j$.
$S_A$ wants any client $C_k, \forall k$ to be able to verify that it has not been tampered with.
I suppose one way to do this is to use assymetric encryption where $S_A$ encrypts $D_j$ as: $E_j = encrypt(D_j, K_{priv})$ us... |
What (obvious) security issues does the following "onion" Distributed Shamir Secret Sharing scheme on a blockchain for the purpose of e-voting have?
The blockchain in this context, is an immutable ledger of records, where any known identity can add a record. Authenticity of source of the records, the privacy of the vot... |
My bank seems to use something like HMAC-based one-time password, and it generates a new code every time I open it, and I could in theory skip a thousand codes (not use them to log in), and then the counter event value would have skipped forwards a thousand for the bank when they try to verify my hash.
I am interested ... |
In the paper describing a protocol for distributed RSA modulus generation, Diogenes, "[they] employ a special-purpose $\Sigma$-protocol based on [Sho00] for proving correctness of exponentiations in a hidden-order group."
If it says this explicitly I haven't found it, but I am assuming the hidden-order group is the $\m... |
In LWE, we know that given reasonable public parameter $A\in \mathbb{Z}_q^{n\times \lambda}$, secret $s\in \mathbb{Z}_q^{\lambda}$ and noise $e\in \mathcal{X}^{n}$, random $r\in \mathbb{Z}_q^{n}$, $(A, b = A\cdot s + e)$ and $(A, r)$ are computationally indistinguishable.
Then, consider another scenario that $A$ is sam... |
Let SE be stateful encryption.
Then, it is well known that the oracle for the security proof becomes stateful too. (We only consider the IND-CPA security game.)
On the other hand, assume that E is stateless encryption.
Then, can the challenger for proving the IND-CPA security of E behavior as astateful encryption schem... |
Although Goldreich-Godlwasser-Micali (GGM) construction of a pseudo-random function (PRF) from a pseudo-random number generator (PRNG) is widely in many cryptographic applications, it needs to consume $2n^2$-bits of PRNG output to generate $n$-bits of PRF output.
Can we make it more efficient with other structures but ... |
I am developing a web application in which each user has some part of his data that is stored encrypted. We are hosted on AWS and I want to use KMS as part of the solution. To not make the solution overly expensive (AWS charges per key) I was thinking of the following solution:
I generate 1 RSA master key in AWS KMS
F... |
Suppose Alice chooses a number $n\in Z_q$ and decompose it to its binary representation $b_0,b_1,...,b_d$. Then Alice encrypts these bits (can be any encryption scheme). Is it possible for Bob (who does not have Alice's decryption key) to read these encrypted bits and create a vector of size $q$ so that each entry is ... |
I understand that you can't discern a private key from a public key, but what if you have thousands of examples of the private key signatures, and you know what the message/cypher is?
Basically, you can't do the hard problem with no clues, but if you have clues (thousands of examples of signatures from that private key... |
Ligero (https://dl.acm.org/doi/10.1145/3133956.3134104) and Limbo (https://eprint.iacr.org/2021/215.pdf) use a somewhat unique MPC model for their zk-PCP where not all parties communicate with each other.
Briefly, in their model there is a sender $P_S$, $n$ servers $P_i, i \in [n]$ and a receiver $P_R$. The protocol be... |
In his paper on pairing based cryptography, Menezes claims that for
$$
E_1: y^2+y = x^3+x+1
$$
the number of $\mathbb{F}_{2^m}$-points is $2^m +1 - (1+i)^m - (1-i)^m$. Whereas this is clear, it is not clear to me how he reaches this conclusion:
In addition, I also do not see why it is relevant (and how one sees/arrive... |
If I have a linear (7,4)-Hamming Code I know that the last 3 bits are the parity bits but I just have seen that there are multiple linear codes like (7,3) for example the code with basis:
$$\begin{bmatrix}1 & 0 & 0 & 1 & 0 & 0 & 0\\
1 & 0 & 0 & 0 & 0 & 0 & 1\\
1 & 0 & 1 & 0 & 1 & 0 & 0 \end{bmatrix}$$
(!Notice that it'... |
Is there any cryptographic method for Proof Of Computation ?
If i am running my program on untrusted hardware (remote server), after some time i want to verify the remote machine hasn't tampered with my program and successfully ran it for required time (and the result/output is correct), how can i verify ?
Is there any... |
I have a question regarding William Wang's paper Shorter Signatures from MQ. According to him the (maximum) signature size is:
$$
2\kappa +
3\kappa\cdot \lceil\tau\log\frac{M}{\tau}\rceil
+
\tau\cdot\left(
\kappa\log N
+ 2 \kappa
+ (n+m)\log q
\right)
$$
The parameters can be chosen in a variety of ways, in the paper t... |
I was sent from Stack Overflow to here (original question). I'm quite new to cryptographic programming. I want to generate TLS certificates on application boot up time. It is a Spring Boot application, therefore Java and that means I'm using Bouncy Castle. Right now I have to decide, what the default algorithm would be... |
2 requirements of Byzantine broadcast (consistency and validity) only state honest node should output certain bit without mentioning what should malicious nodes do.
How do we know the identity of each node?
Could I distinguish honest and malicious node by checking the majority of vote (honest nodes is majority) assumi... |
All examples I find on SNARKs show polynomials of up to degree 3 or 4 but what about polynomials of degree over 5, what is the mechanism that allow SNARK not to be affected by the unsolvability of the quintic while calculating roots? Is there a high degree polynomial example that I could read?
|
I am trying to unscramble received data packets. Each packet is divided into 3 parts ($A$, $B$ and $D$) with equal lengths. In every packet, each of these parts are scrambled/encrypted with an unknown code $C_i$.
We can tabulate these received packets in the format shown in the table below, where $\oplus$ denotes the X... |
Suppose the tuple $(P, a, Q)$ is given, where $P$ and $Q$ are points on an elliptic curve (I'm more interested in Montgomery curves but other curves are also fine), $a$ is a scalar and the notation $[a]P$ is the scalar multiplication. Is there a way to quickly check whether $Q = [a]P$? Specifically, is there a way to d... |
I recently needed (for legitimate reasons) to crack an encrypted pdf sent by a local bank. It was pdf1.7 and the password was 6 digits. cracking it with John the ripper took no time at all. In fact it was faster than normal waiting for the SMS, which is the way I should have gotten the password but that wasn't working.... |
My use case, making public-key encrypted backups, requires deterministic public-key authenticated encryption. I favour NaCl box, but the way it is generally used is probabilistic and it yields different ciphertext due to the random ephemeral Curve25519 key used in the computation of the shared secret. I am wondering, i... |
NIST selected Kyber for key agreement and Dilithium for digital signature applications some days ago. But IDF's MATZOV group, in their paper, broke Kyber and Dilithium and brought the security levels of these schemes below the thresholds defined by NIST for a secure PQC scheme.
Why did NIST not consider MATZOV's attack... |
Maybe the below question is similar to what I was thinking, but I don't understand:
Is BLS signature scheme strongly unforgeable?
Below is the attack method I was thinking of. If know m, can't create a new signature from it?
sk is secret key
pk is public key
m is message
S is signature
e(P, Q) : bilinear pairing
Sign... |
Considering an HMAC algorithm: it shall guarantee integrity and authenticity. I don't understand what authenticity means: that signature could be generated by anyone having the shared secret key (non repudiation is not supported in symmetric crypo-algorithms). Then why could that message be considered authentic if it c... |
I wrote SHA-256 with arrays of integers representing the bits (e.g. [1,0,...,1]), and then I altered it to accept partial values (e.g. [0.5, 0.79, 0.0, 1]), as in each value has an x chance of being '1' and a 1-x chance of being '0'. The hope was to be able to change my input by less than 1 bit at a time to violate the... |
Does GCM spec (NIST SP 800-38D) require tag-size to be fixed for an instance of GCM algorithm (which usually fixes a specific GCM key)?
Asked differently, is the following a legitimate adherence to GCM spec?
There is a discussion going on on GitHub - perhaps knowledgeable folks could comment.
// pseudocode
var one_gcm ... |
If x is the value you're hashing, $t(x)$ is the hash of that value, and $t(x+s)$ is that value with salt, then hashed. You could create a hash table where the key is $t(x+s)$, the value is $x+s$, and compute then store all of the possible strings with a length less than $n$ characters.
If you cracked 2 hashes by guessi... |
In NIST SP800-107, NIST claims that the security strength of HMAC is MIN(security of HMAC key, $2L$). $L$ is the length of the output of the underlying hash function. Let's take HMAC-SHA256 as an example. If the key used is larger than 512-bits, it is truncated to $L$ bits, which is 256-bits. However, if the key is sma... |
So I've been working on a project that aims to allow online distribution of one-time-pads securely. I understand that a pad cannot be reused and must be truly random, and that if it is compromised, the message can be read. The problem is that each pad has to be transmitted in person. I was wondering if this can be done... |
End-to-end encrypted web services (like cryptpad) often include a 128-bit seed in the hash part of the URL (that is not sent to the server), to derive both an identifier that is sent to the server, and the encryption key that is used on client-side only. This seed allows shorter URLs than storing both the identifier an... |
Is there any proof that guarantees that a password with specified features (eg. with random special characters, combination of numbers & letters, some length etc) is secure? If there is such a proof, can you provide it or a link to it?
Edit: I am looking for formal proof, argument of theory that backs the choice of pas... |
In LWE based multi party FHE schemes, the parties should choose a much larger noise when perform joint decryption. In this paper, the author just said that using noise flooding technique to avoid the information leakage about the noise of the ciphertext. Then, how should we choose the smudging noise in a real scenario？... |
I' following along the book "Realworld Cryptography", in chapter 9 where the TLS protocol is introduced, they mention:
Following [authentication], the server can use its certified long-term key pair to sign all handshake messages that have been received and previously sent in what is called a CertificateVerify message... |
First of all, I'm not an expert or even a novice in Cryptography.
I mean this has certainly been implemented by some scummy PRNG developers, which thought of the economics behind it (especially in the casino and similar businesses where the biased distributions would interest people to play from the start but in the lo... |
A supplier is sending me very private information. For security, we are using thedecryptor.com website to encrypt the message. The website provides public and private keys.
We agreed that he will sends me a public key before payment, and a private key after payment.
I would like to know if it is possible to change the ... |
Everyone knows Argon2id is a slow hashing algorithm, and that's on purpose, all is good.
When creating an Argon2id object a lot of parameters are needed to be taken into consideration ultimately settling on a configuration that is strong enough but within the amount of time that you're willing to wait for the operation... |
If there is a uniformly random 128-bit private key scalar $x$, with the corresponding public key $X=xG$ (where $G$ is a well-known base point), how difficult would it be to discover $x$ from $X$?
I am aware that the regular approach would be to use a KDF to derive a private key in the range of the group size of the bas... |
As we know every x value has two y values which are reversed. Just by having the public key, is there a way to determine which side the y value is?
My first approach was to check if the y value is odd or even but after creating many public keys with different secret keys, I didn't find any pattern to check if the y is... |
Out of interest I wanted to test the results of using a floating analogue pin on my Arduino to generate a sequence of random numbers using dieharder.
My working assumption was that it would be a poor source of random numbers and would fail many of the dieharder tests.
I used the following simple code on the Arduino and... |
Let $F$ be a PRF such that $|F(k,x)|=2n$ show that $F_2$ isn't a PRF. Let's assume $F(k,x)=(y_1,...,y_{2n})$ then $F_2(k,x)=(y_1\land y_2,...,y_{2n-1}\land y_{2n})$.
I want to prove $F_2$ isn't a PRF but not sure where to start from since I don't really know much about $F$.
I thought about looking how many 0's are ther... |
This article from Wikipedia claims that "256- and 320-bit versions of RIPEMD provide the same level of security as RIPEMD-128 and RIPEMD-160, respectively".
Is that true or false ? And why ?
|
How good from a randomness point of view are recursively generated sequences using good encryption algorithms?
Let us say I take AES128 which generates good random sequences of outputs for counter inputs. Denote C=E(K,P) to be the output of AES128 with symmetric key K and input block P. Consider the recursively generat... |
I'm studying ECC, so this is focused on elliptic curves over finite fields. I've always seen the quadratic twist $E'$ of an elliptic curve $E$ defined as the elliptic curve with equation $dy^2=x^3 + ax + b$ for some quadratic non-residue $d$. Not a quadratic twist but the. Does this mean that there's some sort of equiv... |
OpenPGP defines RSA secret key in a way which differs from PKCS #1,having the aforementioned values plus U = P^-1 mod Q.
However, OpenSSL seems to work only with (N, E, D) or (N, E, D, P, Q, dP, dQ, qInv) where last three should satisfy the following (as from PKCS #1):
e * dP == 1 (mod (p-1))
e * dQ == 1 (mod (q-1))
q ... |
TL:DR
How can I give a population of N people the chance to randomly pick one token each person guaranteeing those:
Nobody knows noone else's token.
Noone can pick more than one token.
Every person may choose to pick a token or not.
So for N people, after the time window there are M picked tokens and N-M tokens left ... |
Blake2(1024 bit state) permutation (compression function core) is basically a modified ChaCha permutation. One of the modifications is to mix in message bits (key schedule?). Given that blake2 is a hash function, designed to resist related messages (related key attack?) would it not also make a good 1024 bit block ciph... |
Is XChaCha20 with 256 bit key and 192 bit nonce more secure than 128 bit key 128 bit key nonce AES, due to using larger key/nonce sizes? Isn't it supposed to be faster due to being a stream cipher? (in my implementation in turned out to be faster)
Any documentation or sources for further guidance? Thanks
|
There is a plethora of elliptic curves that are close to the 256-bit security level (i.e., fields and groups of approximately 512 bits). Examples are Curve448, P-521, Brainpool-P512.
The standard rationale for 256-bit symmetric ciphers is to protect against Grover's algorithm, which would halve the security level. Howe... |
If i add a password which has (X) bits of entropy as a tag to a picture which has (Y) bits of entropy, will the resulting image have an entropy equal to (X + Y) ?
How many bits of entropy i get if i save a password which has (A) bits of entropy inside an empty text file, then i use "copy /b" command to combine the text... |
I am reading Dan Boneh's book and I am stuck on Theorem 2.11, whose proof is left as an exercise.
The question is: prove that if $\lim_{n \rightarrow \infty} f(n)n^c = 0$ for all $c > 0$, then $f$ is negligible.
Here, negligible function is defined to be a function $f : \mathbb{Z}_{\geq 1} \rightarrow \mathbb{R}$ such ... |
I stumbled upon hummingbird-2 encryption algorithm when I was looking for a lightweight encryption module that can be used in resorce-restrained environments like Network-on-Chips.
A problem I faced when reading https://eprint.iacr.org/2011/126.pdf was that the paper does not mention any decryption procedure and only I... |
I need an encryption algorithm that doesn't require keys and computationally easy to encrypt, hard to decrypt.
Decrypting can involve brute force.
If the algorithm can be applied again and again (encrypt text, then encrypt the encrypted, ...), it would be better as I would be able to scale the time to decrypt as I will... |
I saw a table comparing Hash/Mac/Signatures in this post.
I was wondering if I can integrate digital certificates into it like this:
Hash
MAC
Signature
Certificate + Signature
Integrity
Yes
Yes
Yes
Yes
Authentication
No
Yes
Yes
Yes
Non-repudiation
No
No
Yes
Yes
Identification
No
No
No
Yes
Kind of keys
... |
I am developing a post quantum safe GPG like program, is argon2 quantum safe cryptographically for GPG like application.
|
is HMAC-SHA512 quantum safe , I am planning to use it for encrypt-then-mac scheme with aes256-cfb mode for a post quantum safe PGP like protocol.
|
Would something like this be a reasonable way to implement the double ratchet with libsodium? The sodium port that I'm using is quite limited and does not offer a kdf.
Here is a link to the libsodium documentation page regarding the scalar multiplication.
What crypto_scalarmult_base / crypto_scalarmult does is: "comput... |
I have a question for those that might be familiar with the ligero protocol: Ligero
In this protocol to be using an MPC in the head paradigm: described here. However, in the description of their zksnark they only use interleaved Reed-Solomon checking, but no MPC.
Why is that? Why do they talk about the MPC model they w... |
I have an encrypted password I must decrypt as part of a challenge. Along with the password came a few UNENCRYPTED RSA private keys
From what I understand, all I need in order to decrypt the password is the private key, which I have. However I don't understand what software I need to use in order to decrypt the passwor... |
The lightest, or fastest cipher, that is well known and quite secure like AES. Is ChaCha20 a good option? Are there any better alternatives that are faster but still as secure?
|
I generate two uniformly random 127-bit integers $a$ and $b$.
I calculate $c=a+b$, which means $c$ can always be represented as a 128-bit integer.
$c$ will not be uniformly randomly distributed, but I need to use it as entropy for a private key. I do not have the option of calculating $c=(a + b)\ mod\ 2^{127}$.
How can... |
I researched online and found AES-GCM and ChaCha20Poly1305 aren't post quantum secure. So I am planning to use symmetric AES256 cipher in CFB mode do I need to implement MAC using HMAC like HMAC-SHA512 if I use post quantum digital signatures?
In my program a post quantum key exchange will ensure exchange of shared sec... |
Could you explain with an example what does it mean to be Plaintext-awareness. I have read the wiki definition. It says that "A cryptosystem is plaintext-aware if it cannot genenerate a valid ciphertext without being aware of the corresponding plaintext".
As an example, consider the RSA cryptosystem without padding. In... |
I'm trying to do this cryptopals challenge for breaking ecdsa with biased nonce but everything I do fail to work. I'm trying my attack with 4 signatures and 128 bit bias.
N = 115792089237316195423570985008687907852837564279074904382605163141518161494337 #order of secp256k1 curve
pk = 16627923497236951427941159362308027... |
Lets say we are given BFV encryption of x, let this encryption is represented as E(x). In FHE, the client can decrypt and get the value of x but what if we dont want the client to learn x. This paper suggests that:
the servers samples random r and perform E(x)+r and send that to client
The client decrypts and get x+r
... |
I was wondering if I have to keep my data safe in an age when quantum computers become a reality. Which AES block cipher modes will be secure? Will AES-OCB will be quantum safe if used in a PGP like application?
|
Suppose a 256 bit hash is used (SHA2, SHA3, ...).
How does the Winternitz OTS perform at various signature sizes?
I'd want to compare to a generalized K-teeth Haircomb:
It's signature is $K$ of these 256-bit hashes
the public key is one hash.
We are signing a 256-bit message digest as well
the chain length is approxim... |
I know schemes like BFV, BGV, and CKKS supports SIMD operations where the plaintext is vector of values instead of polynomial. I am wondering if RGSW/TFHE kind of schemes can also support SIMD operations?
As explained in this paper RGSW can be defined as list of BFV cipher texts so I am thinking if it can also take adv... |
Lattice-based PQC KEM has small probability of decryption failure
In an offline setting it can be catastrophic despite being improbable.
Proposed mitigation:
let latice1 and latice2 be two separate instances of the same kyber scheme
lt1pk: lattice1 private key
lt2pk: lattice2 private key
generate entropy string SS
gene... |
I read online that AES-256 is Quantum Safe , so AES-256 used in AES-GCM and AES-OCB should be quantum safe , just wondering is ChaCha20Poly1305 quantum safe , if it is then is it better than AES-256 with GCM or OCB mode?
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