# All Questions

25,861 questions
Filter by
Sorted by
Tagged with
22 views

### Methods and tools for Plain-text Attacks

I have a data block of about 950 byte (previously encoded in QR code). The data is encrypted with an unknown algo+key. The bright side is: I already know many parts of the message, and I have multiple ...
592 views

39 views

### How to find iteration exponent in a cycling attack?

In Simmons and Norris paper they demonstrate the cycling attack with the following example: p = 383 q = 563 s = 49 and t = 56957 ( a prime) The attacker knows the publicly available r = pq = 215,629 ,...
56 views

### What are Practical Primitives based on Lattices, LWE and FHE?

Lattice-based cryptography is being used for several primitives and applications. I know there are newer works for PIR, PSI, ORAM that have seen tremendous improvements due to FHE. In some cases, FHE ...
30 views

### THe operation proof part of paper "Why and How zhSNARK works"

I'm reading the paper "Why and How zk-SNARK works" to learn zkSNARK, and I suffered some problem in section 4.4, when prove the ability of single operation. In this section, it tries to come ...
22 views

### How to estimate the parameter of a lattice signature scheme with lossy reduction?

The parameter of a lattice signature scheme DAZ19 with tight reduction can be choosed to make the underlying hardness problem intractable. How to estimate the parameter of a lattice signature scheme ...
101 views

### Does SSL connection provide integrity?

I'm new to cryptography and I'm trying to implement a secure chat application using OpenSSL. I want to ensure that public messages (which will be shown to all users) cannot be altered during ...
22 views

### Key Switching Error in CKKS

I believe I am misunderstanding something about the bounds derived for the key switching error in CKKS. I will refer to the initial paper, but similar bounds have been derived in all variants I have ...
38 views

### Does the number of bits in the block nonce influence the security of the blockchain?

I know that Bitcoin uses a 32bit nonce that miners iterate over trying to hit the target number of prefixed 0's in the hash. If they run through all 2^32 combinations they then change something else ...
39 views

### How do you quickly find D? (RSA) [duplicate]

with small primes under 1000 each i can find D in a matter of less than 1 second but anything above 1000 seems like it could go on forever! right now I generated huge primes (p = 9504941263, q = ...
96 views

### How strong if I combine two hash functions, such as MD5(SHA256(input))?

If I try to do MD5(SHA256(input)), what is the strength of this so-called double hashing approach? Is it as strong as SHA256, or as strong as MD5, or as strong as ...
36 views

### parameter estimating in lattice signature scheme

when reading [BDLOP18], I run the lwe-estimator with the recommended parameters in Table 2 , but the result of hermite factor is 1.007, this result is bigger than the recommended hermite factor 1.0035
35 views

### Approval of GPG key strategy [migrated]

I am a beginner in anything related to GPG and I have now read quite some stuff about it to get a better idea. I think i grasped most of the concepts by now. I've worked out a GPG key strategy and i ...
90 views

### In AES-256, what exactly forms the extension field $GF(2^8)$?

My question is a little difficult to describe, so let me first start with an analogy In an elliptic curve over a finite field, there are 2 groups - the first group is a finite field over which the ...
67 views

### *-LWE equivalent of Diffie-Hellman $g^{x^2}$ vulnerability

In Is Diffie-Hellman less secure when A and B select the same random number? , the possibility of Diffie-Hellman key exchange producing identical peer keys and the vulnerability of it against passive ...
64 views

### How to check security strength of random k if k is an input parameter of ECDSA signature generation function using openssl-fips

As I understand, 1.The security strength is specified in bits according to https://nvlpubs.nist.gov/nistpubs/SpecialPublications/NIST.SP.800-90Ar1.pdf 2.Security strength is depend on the length of ...
78 views

### What hash based digital signature algorithms exist that have reasonably small signature sizes?

What hash based digital signature algorithms exist that have reasonably small signature sizes? By reasonably small, I mean not much bigger than what you would get with a 256-bit ECDSA (which I ...
61 views

### Is asymmetric decryption guessable?

I am not an amateur in cryptography so this might be a very basic question. I am interested to know if there exist ciphers such that if I encrypt a message with it and then lose first say 300 bits ...
115 views

### Why do people use protocols like PGP, when TLS already exists?

TLS is the standard cryptography protocol on the internet, and many websites use it to secure their communications. However, for personal use, most people use other protocols like PGP, instead of ...
37 views

89 views

### Unhash possible? How got this user the unhash?

in this post Why can't we reverse hashes? there is an unhash of "Hello World". How did that work? If there is no function to find it, where does it come from?
141 views

### What are the misconceptions of IBM's CEO Arvind Krishna talk on the "Axios on HBO" about the quantum computing

IBM CEO Arvind made a talk in HBO's Axios program. It seems that there are misconceptions/misleading/flaws in reasoning etc. What are those! Some of the details of the speech is given as; IBM says ...
75 views

### What is reaction attack?

In the paper of "Reaction Attacks against Several Public-Key Cryptosystems" CiteSeerX link, reaction attack is defined informally as "Obtaining information about the private key or ...
34 views

### How are cryptographic tokens and secret keys different?

Can someone throw light on the differences between tokens and secret keys? I understand that "tokens" are crypto artefacts "introduced" into a system by an external party in order ...
22 views

### Securely and Deterministically select a combination of objects from hash (cryptographic seed)

I am working on a project that is using a bit-commitment concept to authenticate information. I need to select a combination of objects securely from a secure hash, then distribute that hash later. ...