# All Questions

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### what is multi authority based weighted attribute based encryption ?? is this the current technique deployed in cloud?

As i'm interested in cloud computing domain, i have just got to see that MA-WABE is used as a cryptographic technique in cloud. can anyone brief about this technique?.if any algorithms present which ...
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### FIPS 186-4 seems to have an excessively complex q generation

So in DSA you have two primes - p and q. q is N bits long (let's assume 160 bits) and p is L bits long (let's assume 1024 bits). Here's what FIPS 186-4 says about generating the q parameter for DSA: ...
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### Finding Elliptical curve points and encoding text using them

I recently got into learning Elliptical curve cryptography and are currently building a project in C#. Everything is working well so far, I can encode and decode points, and thanks to this forum I ...
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### Questions regarding parallel AES CTR with merkle trees

I'm planning to implement a parallelizable variant of AES to end-to-end-encrypt files in a web application. As a mode of operation I'm most likely gonna use CTR mode with a 64 bit IV and 64 bit ...
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### Store and share data on intranet website

I'm developing an intranet for a company where admins are sharing a huge excel file containing all the necessary password, on the common TSE. I've managed making them encrypt it with a common password ...
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### Is security against semi honest adversary inheritable?

I have a two party protocol, let's call it $M$. At some point, there are $k$ steps, each one involving an oblivious transfer protocol, which is known to be secure against semi honest adversaries. ...
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### Applying machine learning algorithms to homomorphic encrypted data

I have a basic understanding of encryption and I got back to the topic because of an interesting site that encrypts financial data using homomorphic encryption (HE) and I would be happy for any input ...
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### Security model scalar multiplication in NaCl

I'm having trouble understanding what the “security model” for “scalar multiplication” in NaCl is. Security model crypto_scalarmult is designed to be ...
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### What characters are valid in PGP encrypted and signed messages?

What characters may be present in a PGP encrypted message or a PGP signature? For example, do encrypted messages only use the Roman alphabet + some numbers and symbols? Can the character set be ...
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### Finding Linear Redundancy by counting the number of distinct frequency distributions of absolute walsh transform

I am writing a program to find linear redundancy in 4x4 s boxes. Is the number of distinct frequency distributions of absolute walsh transform a direct measure of linear redundancy in s boxes? byte[] ...
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### Can a low density subset sum problem be intractable?

Hardness of a subset sum problem depends on it's density. Is it possible for a subset sum problem to be intractable even if it's density is less than 0.9408?
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### Is calculating HMAC from hashed input a good idea?

The original HMAC algorithm is as follows: H(K XOR opad || H(K XOR ipad || text)) What if text would replaced with H(text)?...
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### Proof that LFSR (with XOR feedback and nonzero seed) will never hit state of all 0s

Does anyone know a good proof that a LFSR (with XOR feedback and seeded with non-zero starting state) will never enter zero state? It is obvious that a zero state will always get stuck in a zero ...
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### XOF/derivation as OTP

Probably a stupid question but I haven't seen it asked before... What would be wrong with expanding a key to the length of a given plaintext (using Shake or scrypt) and using that as a OTP on the ...
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### Zero-knowledge proof for subset sum problem?

What is the currently most efficient (interactive) zero knowledge proof/argument for the subset sum problem? The most recent relevant paper I have found is Efficient Modular NIZK Arguments from Shift ...
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### What are I2OSP & OS2IP in RSA-PSS verification?

I started working with RSA two weeks ago. But I coudn't really understand how exactly I2OSP & OS2IP are working. I am using some open source for signature verification through RSA PSS algo. I am ...
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### Security of a self-decrypting block-cipher?

If I have a block-cipher like for example AES, a plaintext $x$, we use different function to encrypt and decrypt : $\text{encrypt}(x) = y$ , $\text{decrypt}(y)=x$. Now, if we build a function with a ...
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### Authentication protocol which detects client impersonation from another machine

Consider following authentication protocol. Client ClientA knows some initial secret KeyA shared with server. Client also knows IP of legitimate server. Now when client wants to establish connection ...
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### Detecting encryption in real-time?

Is there anyway to detect encryption in real-time through a common signature or pattern recognition. Say, a file is being encrypted using an AES-256 cipher, if I have access to the file stream - can ...
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### What exactly is a “garbled circuit”?

There are plenty of questions here about the details and how-to's of "garbled circuits", but I have not seen anything that defines what garbled circuits are. What exactly is a garbled circuit? What ...
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### RSA: revealing the modulus factorization by choosing a bad message

I started reading the book Cryptanalysis of RSA and its variants by M. Jason Hinek and I stumbled upon a phrase that intrigued me: plaintext messages that are relatively prime to the modulus (i....
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### How can I find all points on an elliptic curve?

I have an elliptic curve $$y^2=x^3 + 8 \times x + 6 \mod 13$$ How do I find all the points on this EC? Also, could you give me more examples?
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### Bit level permutation

Could anyone explain how secure is bit level permutation? What is the most serious threat against the security of this kind of cipher?
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### Key exchange using ECDH vs ECIES?

I'm a beginner to ECC crypto programming. Does any one explain to me the difference with using ECDH for shared key exchange and use of ECIES by encrypting shared key with the public key of the ...
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### Building a cryptography system by combining a block cipher and a stream cipher?

I have to come up with a design for a cryptography system by combining a block cipher and a stream cipher. I can't seem to come up with anything on my own. Can someone point me in the right direction ...
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### Garbled table for 3 inputs

I have a truth table of a full adder with 3 inputs (A,B,Cin) and 2 outputs (S, Cout). How can I create a garbled truth table? I mean, in the general form it is ...
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### what are the NTRU keysize and application in industry?

I'm a student currently working on a research project on the NTRU cryptosystem, I've read some papers about this cryptosystem, and in those papers they are talking about keysize, is it the size of the ...
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### pairing parameters in PBC library

I would like to know what are the pairing parameters of PBC library and what are they used for? Here an example where they are used. I noticed that we can give any file in the param subdirectory. Is ...
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