All Questions
27,478
questions
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6
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identify how to solve this cipher please! its fun and a mystery
I have roughly 25 three digit numbers between 0 and 200, that are a cipher. if i know what some letters are (for instance a=2, c= 9, and f-3) then how can i solve for this?
- 1
0
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0
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9
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Data corruption to protect the encryption?
On KeePass help center it's stated that:
... if the header of the database (first few bytes) is corrupted, you're out of luck, too: the repair functionality won't be able to restore any entries (...
- 57
0
votes
0
answers
15
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Does the p value in randomness tests provide any real value?
In the dieharder test suite there are things like:-
diehard_3dsphere| 3| 4000| 100|0.56011310| PASSED
and in the NIST IID (brief mode) and randomness ...
- 14k
0
votes
0
answers
18
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Why are ZK proofs so dominant in verifiable computing?
There seem to be many ways of verifying computation, and many classes of interactive proof systems which aren't ZK.
That being said, most "validity proofs" in blockchain (which seems to be ...
- 11
0
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0
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13
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Hash tree that covers 16 data block
For a hash tree that covers 16 data blocks, how many hash checks do you need to perform to localize the error? Assume that error occurred on only one block.
2
votes
2
answers
128
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Understanding the small cofactor attack with Elliptic Curves of non-prime order
I came across 2 older answers (2 different but similar questions on the small cofactor attack) which cover this attack.
https://crypto.stackexchange.com/a/12614/3941
Here the attacker replaces the $...
- 1,667
1
vote
1
answer
349
views
Diffie-Hellman over $GF(2^{128})$
Can I use Diffie-Hellman over, say, $GF(2^{128}) \bmod$ irreducible poly in $GF(2^{128})$ instead of $GF(p)$?
If not, why?
Or increase it to $GF(2^{2^{\text{whatever}}})$.
0
votes
1
answer
28
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ed448 generator choice in supercop
Mike Hamburg proposed the Ed448-Goldilocks curve and submitted a software implementation for it to the SUPERCOP project.
Below you can see that MH picked a generator (or base point) that has a y-...
2
votes
1
answer
140
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Zk Proof to Prove that I know the secret x of y = HASH(x)
Lets say I know a secret value x.
The hash of x, y = H(x) is public.
Is there any zk way to ...
- 123
0
votes
0
answers
36
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Why g is 2 and 3 to derive the lambda and beta values for endomorphism on the secp256k1 curve?
As you can seen here, in hex, N and P are:
N = FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFE BAAEDCE6 AF48A03B BFD25E8C D0364141
P = FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFE FFFFFC2F
The ...
- 1
1
vote
1
answer
38
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Security of Reusing a One-Time Pad with Complement Messages with Errors
Let's say I have two binary messages ($m_0$ and $m_1$) of length $n$ which are bitwise complements of each other such that $$m_0 \xleftarrow{r} \{0,1\}^n \text{ and } m_1 = \overline{m_0}$$
If I ...
- 11
0
votes
1
answer
71
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Should I use hash of passphrase as AES256 key
As title I have a password-like passphrase (8 chars at least) that is then hashed with argon2(with the salt is SHA256 of that passphrase).
Then use it as AES256 key along with a random IV generated by ...
- 41
-1
votes
1
answer
38
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How to read clock cycle from latency tables?
I see many papers that compare the latency of the signature schemes in terms of clock cycles by two-three numbers. I don't know why they write 2-3 numbers instead of one number to represent clock ...
0
votes
1
answer
37
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Equivalance of encryption and decryption in DES under bruteforce
I am studying the vulnerability of DES algorithm.
Let there be a DES system with 5 keys, 56bits each. Encryption works as follows: (It's in this order on purpose)
$C=DEC_{k1}(ENC_{k2}(ENC_{k3}(DEC_{k4}...
-1
votes
0
answers
18
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Elgamal Problem, cant find the right answer, If anyone could help, would appreciate it [closed]
Joe has a public and private key pair (u𝑘𝐴, p𝑘𝐴) for ElGamal signature. Suppose that Joe signs a message for Arthur every day. If Joe uses the same random number 𝑘 in all signatures. Analyse the ...
- 1
0
votes
1
answer
39
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Encrypting data before Saas-solution
The compliance department is asking me for recommendations on encrypting data before Saas-solutions. Meaning that the Saas-solution should not be able to see the data when stored and processed.
...
0
votes
1
answer
36
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Difference between DSA and RSA in terms of signature generation
For DSA, if the same message is signed multiple times on different occasions, the signatures will differ because the random value k is generated for each signature. This is not true of RSA signatures....
- 129
6
votes
1
answer
1k
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is XChaCha20 stronger than ChaCha20?
Some of the encrypted messenger apps and password managers use extended version of Bernstein's ciphers and some of them not.
Viber-Salsa20
Wire-ChaCha20
Threema-XSalsa20
Sid-Salsa20
Nordpass-XChaCha20
...
- 61
0
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0
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34
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RSA / RS256 Encryption with the public key I have
safe to say I'm a complete beginner when it comes to cryptography... I believe the example output below is some sort of RSA (or RS256) encrypted string, and was just curious whether it'd be possible ...
- 101
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0
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36
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Clarification for CCA security (or - why is the following not a Rabin CCA attack?)
In three different, highly reputable sources (e.g. "Introduction to Modern Cryptography" by Katz and Lindell, 2007), the definition of CCA attack doesn't allow the adversary to decrypt the ...
- 215
1
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0
answers
51
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Is ChaCha20 + HMAC(SHA3) output indistinguishable from randomness?
I was wondering, if the output of following type of ChaCha + HMAC scheme is indistinguishable from randomness:
...
1
vote
1
answer
18
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Clarification regarding Rabin Cryptosystem being CPA (Chosen Plaintext Attack) secure
Do I understand correctly that the textbook Rabin encryption scheme, where there is no random padding (as is also required in RSA for it to be CPA secure), is not CPA secure? (it is deterministic ...
- 215
1
vote
1
answer
65
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Why Can't I Use an Nacl Sign Keypair for Encrypt and Decrypt Operations?
I'm aware that the difference between the NaCL sign keys vs the box keys is that the secret key that comes from the NaCL box keypair is the ...
0
votes
1
answer
48
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How to verify an ES256 (ECDSA using P-256 and SHA-256) signature with window.crypto.subtle? [closed]
I'm having trouble figuring out the right parameters to verify a ES256 signature that was created with an ECDSA P-256 public key in web crypto. Below script outputs different results for Node.js vs ...
- 105
0
votes
2
answers
78
views
Is it possible to create digital signature with specific p, q, e values by using OpenSSL?
I'm trying to create the digital signature by using these parameters and RSA algorithm:
p = 645353605880701501120167331073
q = 350784310265709643169455170929
e = 19
message = "G’day mate! As we ...
0
votes
1
answer
43
views
Precise heuristic for size of a uniform sample in $(\mathbb{Z} / N \mathbb{Z})^\times$
I'm primarily a mathematicians dipping my toes into cryptography, and I have often seen/heard cryptographers use the heuristic that a uniformly random sample $a$ from $(\mathbb{Z} / N \mathbb{Z})^\...
- 103
0
votes
1
answer
55
views
Shamir secret sharing, recovery of keys which have 0 bytes in front of them?
From what I know SSS creates a polynomial with a0 = secret key and interpolates it on recovery using k coeffs. if a0 is a number,...
0
votes
3
answers
47
views
Do digital signatures without contextual information protect you against signed messages replay attacks?
Consider this scenario:
A signs a message to B using A's private key. A then encrypts the signed message with B's public key. A sends both plaintext and encrypted message to B so that B can verify.
...
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0
votes
0
answers
60
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is it possible to secure password management using one time pad cipher. I have created a protocol which uses one time pad password storage [closed]
I thought of a secure protocol for password manager. It has single user .My one time pad supports 36 characters [ numbers 0 - 9 and all 26 alphabets , encryption process is similar to method mentioned ...
2
votes
2
answers
43
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For an asymmetric bilinear pairing, can I get $g_2^t$ from $g_1^t$?
Let $e:G_1\times G_2\to G_t$ be an asymmetric bilinear pairing, $g_1$ be a generator of $G_1$ and $g_2$ be a generator of $G_2$. Can we compute $g_2^t$ from $g_1^t$ when $t$ is unknown?
- 21
1
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0
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57
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Breaking RSA with P,Q LSB bits using LLL Lattice reduction
This question is someway correlated to Breaking RSA with P,Q LSB bits but more specific.
I would like to use LLL to fully reconstruct P,Q given some LSB bits of P and Q in an arbitrary base B.
Let's ...
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-1
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1
answer
95
views
What is the importance of superencryption?
Please, can any extensively explain the importance of super encryption in relation to attacks experienced by single standard algorithms
-1
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0
answers
41
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Need help understanding and decrypting this rsa code please [closed]
this is the code for rsa common modulus:
...
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0
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1
answer
38
views
Unexpected Behavior Working in Prime Order Subgroup with Java BigInteger Class
I'm implementing a searchable symmetric encryption scheme, developed by others, for my own personal enrichment. The original research is located at the link: https://eprint.iacr.org/2013/169. I'm ...
- 1
0
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0
answers
37
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ZKP proof of copying a vote without interaction with the copied
So I had a question about ZKP protocol, I had to create one by myself and I am not sure if it is valid.I'll try to explain, if you need any precisions, don't hesitate to ask.
In an election system, ...
- 1
1
vote
1
answer
32
views
Can we achieve statistical Completeness, Soundness and Zero Knowledge in an Interactive Proof?
The question is mainly stated in the title, sorry for it being a bit small of a question. I was reading about ZK proofs and I was wondering what do we know about their limits only their properties. Do ...
- 661
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0
answers
32
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How shall I imagine the prefix Chosen Plaintext Attack (CPA) on ECB mode in practical terms?
I know quite well how prefix attack works for ECB mode as described in https://www.linkedin.com/pulse/short-note-prefix-chosen-plaintext-attack-cpa-ecb-mode-hannes-salin
Great, but in most situations ...
- 1,447
1
vote
0
answers
25
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What should argon2id parameters be
I plan to use it locally on mobile devices. These seems to do not offer computational power as good as on a server.
So what could be a secure argon2id parameters that run around 1s since offline apps ...
- 41
2
votes
1
answer
27
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Merge two multisignatures
I want to know if there is a multisignature scheme that allows the merging of two multisignatures for the same data but by two different sets of users, and without knowing the corresponding private ...
- 231
0
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0
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20
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terminal commands for socket.connect, socket.send, socket.recv equivalents with tor [closed]
I ultimately failed at finding a way to use tor from within python on different os.
I thus now seek a way to send files from hard-drive via tor to a known socket and receive the server's response file ...
1
vote
1
answer
30
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Which ZK proving systems are statistically vs computationally zero knowledge?
I was curious which of Groth16, Halo2, Bulletproofs, etc have statistical vs computational zero knowledge guarantees. This would inform post-quantum zero knowledge as well, since I imagine that past ...
- 113
1
vote
2
answers
53
views
What do we know about the relationship between IP, ZKP?
The question is fairly simple and is actually stated in the title although I will elaborate a bit further on it. Also, I'm not really sure if this belongs here or it partly belongs to cstheory....
- 661
4
votes
1
answer
91
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What is the rationale for including addition in SHA-256?
Short Version: SHA-256 uses addition alongside a variety of bit-wise operations. What's up with that?
I was reading a description of how SHA-256 worked and it included a description of the various ...
- 701
1
vote
2
answers
45
views
Linear complexity of real and complex sequences
In cryptography output sequences of stream ciphers are binary valued (or more generally finite field valued). However mathematically sequences over real and complex variables can also be generated by ...
- 121
2
votes
3
answers
116
views
RSA different ciphertext for the same plaintext
General
My goal is to encrypt some strings and store them in a database.
I am using RSA OAEP in Go (Golang):
...
- 21
1
vote
1
answer
29
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How to complete this proof of statistically indistinguishable distributions?
Given that:
$$ SD\bigg( (r, \langle r, s \rangle),(r, b) \bigg) < \mathrm{negl}(n)$$
where $SD$ stands for statistical distance, $r$ is random uniform in $\{0,1\}^n$, $s$ is random uniform in $S \...
- 215
0
votes
1
answer
83
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How is Diffie-Hellman linked to AES?
I have just learnt about Diffie-Hellman and AES. However, I cannot seem to understand how they link.
My initial idea was that Diffie-hellman is used to transfer a key for AES decryption. After further ...
- 3
0
votes
0
answers
17
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Encrypt clients files and shares
I have to encrypt data (files) of client on server side and only the client can read theses files (admin can't see name and content of file).
To resolve this, I have the idea to just use something ...
- 1
0
votes
1
answer
31
views
Increase encryption key length in Shamir secret sharing
Can Shamir's secret sharing work on any size of key?
0
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0
answers
15
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Only alphanumeric encoding identification [closed]
I've received an advertising email from a Chinese conference and I was surprised to find a 10000 (exactly) characters long string at the end of it:
...
- 101