0
votes
1answer
111 views

Does MD5 hash have quasi commutative property? [duplicate]

I am implementing a one-way accumulator using MD5 hash, wondering wheather it has quasi commutative property or not.
0
votes
1answer
50 views

Usage of 3DES for single block

I have a device, HASP, which has functionality to encrypt 8 byte data using 3DES in ECB mode, with three different keys, I am interested how secure is this? I know it might not be most secure, but how ...
0
votes
1answer
50 views

Can a Cramer-Shoup public key have two different private keys?

Since I am new to the Cramer-Shoup algorithm, I would like to know: Is it possible to have two different private keys for a public key due the key pair generation algorithm that Cramer-Shoup uses? I ...
0
votes
1answer
59 views

Creating a message authentication scheme

I have such situation. I have a device like dongle. But it has certain limitations. For example, it can only have implemented encryption and decryption functionality. The availability of ciphers ...
0
votes
1answer
36 views

Subscript R notation for the finite fields

I'm trying to understand the notation used in the literature for Pairing-based cryptography. I know (and I hope I've understood it well) from Wikipedia that $\mathbb{Z}_p$ is the finite field of ...
0
votes
2answers
2k views

RSA PCKS1 v2.1 RSAES-OAEP algorithm

Using RSA public key (n,e) the encryption of a message is c= (m^e) mod n and the corresponding message is decrypted as ...
0
votes
0answers
208 views

How to verify a signature with openssl methods from the ECDSA class?

I'm trying to verify my signature like I explained in my question before. But I have some problems to program my own verification without the verify methods of openssl. Therefore I'm going on to use ...
-1
votes
1answer
58 views

Should we use modulus switching when dealing with ciphertexts encrypted in different rings?

Having a homomorphic encryption scheme like BGV or LTV-FHE at some point it is possible in the homomorphic evaluation to deal with ciphertexts that are encrypted with respect to different moduli. ...
-1
votes
1answer
667 views

With HMAC, can an attacker recover the key, given many known plaintext/tag pairs?

Given many pairs of $(m, t)$, can the attacker compute the key $k$ satisfying $\text{HMAC}(k,m) = t$? (Assume that $k$ was chosen at random.)
-1
votes
1answer
82 views

Can we use merely permutation to hide a message?

This question is related to this: When all shares of a secret are given to adversary as a permuted matrix I think the below question is a simplified version of that. Assume we have a 40-bit ...
-1
votes
1answer
213 views

Reversing a Psuedo Crytographic Hash [closed]

I'm trying to get a better understanding of cryptographic hashing. Take the example transformation function below, is it possible to reverse this formula to solve/isolate for message[i]? ...
-1
votes
1answer
49 views

What's the best way to pad a message?

Currently my padding is adding a string of random characters $ l(N)/3 - (l(M) + 1) $ Long and just adding it to the messages, is this sufficient? $l(x)$ = length of a variable
-2
votes
2answers
125 views

Why are there so many stream ciphers out there and even ongoing research?

What make them better than OTP using a CSPRNG initialized with a secret key?
-2
votes
1answer
349 views

Cryptography based upon neural networks [closed]

I would like learn about use neural networks in cryptography. Is there any research literature on this subject? What should I do to learn about the subject? I am taking short course in neural ...
-3
votes
1answer
2k views

Is it possible to generate an RSA SHA1 signature only from a public key?

Is it possible to generate signature only from Public key. See example below where i have valid signature but what if I change hash ? Is then any way to do this? Public key(160 bytes): ...
-3
votes
2answers
205 views

Selection of cryptographic functions for OAEP

I can't understand how the "cryptographic functions" are to be selected RSA + OAEP which are used in OAEP. How to choose these "cryptographic functions"(G and H)?
-5
votes
1answer
163 views

How is this for security? [closed]

I have a function in a C++ program that uses a incrementing integral pattern within a algebraic formula. Each time there' a new character inserted, it uses this ...

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