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# Applied Cryptography - Science topic

Explore the latest questions and answers in Applied Cryptography, and find Applied Cryptography experts.

Questions related to Applied Cryptography

May you please name some good books on Blockchain technology?

I need to test CSPRNG using ENT (http://www.fourmilab.ch/random/). I produced random stream from the generator and stored it in a text file as a sequence of 0s and 1s. I've tried different samples but all of them have failed. To check whether I'm performing the test correctly or not, I look on the internet for a pretested random bit sequence and it has failed as well. Do you think the issue is with the tool or with the form of the input to the tool?

In socialist millionaire problem, two millionaires learns whether their wealth are same or not without revealing detail wealth. It is a step in protocol where Qa = g^x and Qb = g^y, where x and y are wealth, g is base of the discrete logarithm. a) Is it not computational overhead on users if value of x and y are huge? b) If I want to replace x and y as string in place of numbers, then how may I do it?

Today, in 2019, I see an increasing popularity of playing a Capture The Flag (CTF) by Cybersecurity students.

What are the advantages and disadvantages of playing CTF's in relation to developing the right skills for Cybersecurity students (Bachelors and Master degree)? Does it ad value to the cybersecurity skills gap? On what way it does or does not?

CTF definition from Wiki: en.wikipedia.org/w/index.php?title=Capture_the_flag#Computer_security

There are a lot of competitions online and offline. Just a few examples:

Offline: ecsc.eu (Europe), defcon.org (Americanas)

Example Curricula from ECSC: ecsc.eu/about/ecsccurricula.pdf/download

Good reads about the intersection of Cybersecurity and education (related to playing CTF's) are also welcome.

Other questions i have in mind:
1) How does playing CTF games ad an value to the quantitave and qualitative cybersecurity skills shortage worldwide?
2) Can playing CTF's be a (partial) replacement for Cybersecurity-education (under- and graduate level)?
3) The quality of a CTF strongly depends on the developer(s). Is there (some kind of) framework to measure the quality and levels of CTF's?
4) What is the future of CTF's? (Serious gaming/cybersecurity simulation environment/other)
5) How can we make CTF's more reality based / realistic?
6) The sooner students start with playing CTF's, the better?

Sources for CTF frameworks:
https://github.com/cliffe/SecGen
https://github.com/CTFd/CTFd
https://github.com/easyctf/librectf
https://github.com/facebook/fbctf
https://github.com/Gallopsled/pwntools
https://github.com/koromodako/mkctf
https://github.com/legitbs/scorebot
https://github.com/mcpa-stlouis/hack-the-arch
https://github.com/moloch--/RootTheBox
https://github.com/Nakiami/mellivora
https://opencyberchallenge.net/
https://github.com/UnrealAkama/NightShade

Good reads:
https://trailofbits.github.io/ctf/
https://github.com/s1gh/ctf-literature
https://www.endgame.com/blog/technical-blog/how-get-started-ctf

https://doc.lagout.org/security /Packt.Kali.Linux.CTF.Blueprints.Jul.2014.ISBN.1783985984.pdf

Hi,

As per the definition of logic obfuscation, obfuscated circuit stays in obfuscated mode upon global reset (i.e. initial state) and generates incorrect output; upon receiving correct initialization sequence it enters into functional mode and generates intended outputs.

This is fine with respect to the design that does not connected with any further critical systems. If at all, the obfuscated logic needs to be connected to further safety critical systems, won't incorrect value generated in obfuscated mode affects the critical systems??

In such case, how to apply logic obfuscation??

Thanks in advance.

Suppose c=E(m,k) be the bit representation of the encrypted value of the message m with the key k. Suppose, for each t, there exist an x that has the following relation:

W(E(m,x) Xor E(m,k))=t.

In this relation, W is the weight function that represents the number of 1s. Suppose there is an algorithm that can find x for each t>1. For what values of t, this algorithm can be considered a threat to block cipher E?

What are some examples of Multi secret sharing schemes actually being used in real-world applications?

I am working on an approach to prime factorization in polynomial time using a modified AKS primality test. Do you think that the following approach will work?

-----

If a test similar to AKS for divisibility can be created, which given any w,n with w <= sqrt(n) tells us whether or not n is divisible by any k:1 <=k <= w in polynomial time, we can factorize n in polynomial time. This can be achieved by constructing a binary search to find the factors of n in log(n) time. In case of w = sqrt(n), this test should become trivial AKS primality test.

-------

Dear Colleagues,

From relation:

P=ε_0 χ^((1)) E

I suppose that in an isotropic medium, χ^((1)) is the scalar quantity, vector P and E are in the same direction, while for an anisotropic medium, χ^((1)) is the tensor quantity, vector P and E are different in direction. However, my professor said that the above statement is not true in some special cases. Could you tell me which is the those cases?

Thank you and hoping for your insightful response.

How to prove onewayness, weak collision and strong collision of Hash function. Please provide explanation about formal proof. Please attach a literature if you have.

I need a matching algorithm between a collection(Xi) and a collection(collection(Yj))

knowing that Collection()Yj may have elements in common

I explain with an example:

suppose we have a web service S with 3 inputs (I1,I2,I3)

I1 can be provided by services A, B, C, D

I2 can be provided by service A,E

I3 can be provided by services F

I need an algorithm or a function to find the best combinaison between the available services to provide the input of S (I1,I2,I3)

Collection(Xi)={I1,I2,I3}

Collection(Collection(Yj))= {{A,B,C,D},{A,E},{F}}

Thank you.

I am looking for step by step procedure to find the crystallite size and microstrain by warren-averbach using xpowder and how can we interpret the plots. is this method able to estimate the dislocation density and is there empirical equation to estimate the dislocation density using xrd.

the attached picture is for the analysis using xpowder. in the instrumental profile, how can i find the instrumental broadening and compare it with measured pattern.

looking for help to know much about the correct procedure from your wide experience.

best regrads

P.S. Can we Use the experimental sample instead of the standard one to estimate the instrumental broadening after annealing.

We know that, the most classic problem was distribution key... In asymmetric cryptography algorithm this problem a little bit solved but the impact is it take it too long process, so one of solution could be used was protocol cryptography with symmetric cryptography algorithm, i just wanna ask all researcher which is the best protocol cryptography is it Thres-Pass, bit commitment protocol, secret sharing, secret splitting or else.. please give me your answer

Why is elliptic curve cryptography not widely used compared to RSA?

I am trying to apply cryptography for sensor data in Contiki/Cooja simulator.

Is that possible to implement in Cooja simulator?

or do we need some special tools?

I would like to know about the encryption systems used in SMS coding (both for the purpose of transmission data security) in mobile modern phones.

HVC : Halftone Visual Cryptography

In HVC we generate halftone image then its complementary after that we embed the secret image into them. by stacking the two shares we recover the secret. my Q is when we calculate some metrics such as Recall F-measure between which images ? is between halftone image before embed the secret and after embed the secret

Dear friends and research gate community

Can anyone suggest any recent method suited to color images?

I need a fast method with good compression ratio. Also, I would like to know if someone has an article comparing the performances such as complexity along with other achievements.

Thank you.

Best regard.

If I apply a LSB based algorithm for hiding data in an image, how can I calculate the possibility of the data being detected in steganalysis? Or finding the data bits that are encoded?

If implementation of the basic modular addition, multiplication or exponentiation is done from scratch (eg. implementation of Carry Save adders or Montgomery's multiplier), one might not be sure of its efficiency in terms of throughput or area of chip. One the other hand, if standard packages exist, then it would be a lot easier to implement.

my research is about hiding secret data into ePDF, using TJ operator, i will embed the integer number of secret data to Tj operator. but now, i am confusing how to get a TJ operator of PDF and return it from TJ operator to PDF file.

i have attached the reference paper

Thank you.

I have a question about the article “efficient and multi-level privacy-preserving communication protocol for VANET” by H. Xiong et al. I need the ID of malicious vehicle, but i could not prove how I can get its public key from the equation given in the part of OBU fast tracing on page 3. How do I prove if this equation is right?

(C

_{i})^{q}.B_{0}=pk_{i}I need to implement ECC algorithm for RFID passive chip.

taking about energy and tension ?

My question is about generating reliable keys in PKI (clients generate their own keys under the supervision of CA). We have an Authority Center (CA) generating some public and private keys for each client (more than one pair for each client). One method for sending keys to client is sharing a secret key between CA and client, and then sending key pairs and certificates by symmetric key encryption (with secret key). But overhead will be high, so i need an efficient method with low message overhead and time for key pairs transmission. How can i do it?

I know it's not possible to generate multiple public keys with unique private key, so i need a method that generates multiple key pairs for a specific client that are related (e.g. they are derived from a shared secret key) and CA can found their relationship, but other clients cannot find this fact.

The inventors of the AES Rijndael state that there are no 'linear' mathematical relations between plaintext and the corresponding ciphertext when passed through Rijndael. How can you prove this statement? What is the process to prove or disprove the presence of a mathematical relation between a pair of plaintext and ciphertext of any cryptographic algorithm?

I have to send the encrypted data to more than one cloud storage.I have a same question as Neetha Sharma do. Where can I insert my code in a simulation program example. First of all, Which example can I take for my project?

In generic secure computation protocols, garbling have to be followed with the oblivious transfer. Can anyone suggest me the best two-party OT protocol? Implementation details will also be appreciated.

Hi All,

I have designed a simple method to synthesize 8x8 Substitution-box based on the concept of chaos function and search theory. I am asked to define equivalence classes to test number of S-boxes can be generated from the method. Please let me know how to determine and define the equivalent classes of 8x8 S-box.

I am trying to implement the video watermarking based on visual cryptography. I have created two share of a image in '.bmp' formats. How these two shares will be embedding in the video while using the frequency domain.

I have divided the video into parts ( Suppose the video consisting 300 frames. In this way each part is having 150 frames each) to embed these share in two different parts. I have extracted the Y component of each part of the video. On which I had applied the DWT. Extract the HH Band. Apply SVD. And get the singular matrix.

How could I process the two share of transparencies in order to embed into the singular value obtained of these two parts of video as indicated above. Also requested to please tell me the extraction process of these two transparencies from watermarked video ?

**You are most welcomed to informed me about any other method to implement the visual cryptography based video watermarking.**

what is the purpose to prove security in this way?

I am talking about game based definition for CCA and ID-CCA

It could be thought this question as a different approach if it is compared with research recently.

The AES algorithm uses the irreducible polynomial x^8+x^4+x^3+x+1 for multiplying with MDS and inverse MDS matrix for encryption and decryption, respectively.

Can we change this polynomial with another one?

Should we redesign the MDS matrix if polynomial is changed?

The modern Enigma encryption machines have same gear sizes, so the encryption can be a 1-to-1 function. I am trying to fin a way the encryption could work with different gear size, but apparently there is no way because if the proportion is altered then the encrytion values for some letters wont be the same.

I use the online gear generator for implementation: http://geargenerator.com/

I'm asking for the most efficient and secure

Which encryption approach is better especially over a network. Cryptography or Steganography?

I am looking for a performance analysis of Craig Gentry scheme. I am interesting to know how large is the ciphertext of a single bit after encryption? How much it takes to encrypt a bit, decrypt a bit and perform (addition, multiplication) operations between two bits?

Can any one help me to find these information?

Thank you.

^{Integer factorization is very important for defining the security level of public key cryptography. What are the factorization methods available to factor a large integer greater than 1024 binary bits ?}

^{Is it possible to factor such large integer ?}

We know that LFSR are used in the design of stream ciphers. Block ciphers with modes of operation such as counter are also used in the design of stream ciphers. What other things are available to design stream ciphers ?

I am looking for 16x16 MDS (Maximum Distance Separable) and involution matrix. Involution matrix is a special matrix where multiplication with itself results in unitary matrix.

I have a new method, so the comparison among methods play a crucial role in improving this method.

We need new cryptographic algorithms and information security techniques to rise our life security in the future.

Hi,

I need a clarification regarding domain of hash functions. I have defined a bilinear pairing based system as follows:

Let G1 and G2 be cyclic multiplicative groups of prime order p generated by g1 and g2 for which there exists an isomorphism phi: G2 -> G1 such that phi(g2) = g1. Let GT be a cyclic multiplicative group with the same order p where e : G1 x G2 -> GT is a bilinear pairing.

Now, I have some computation for hash functions:

1) H1=H(t, r, d) where r = g1^x, t is timestamp say belongs to Zp*, x belongs to Zp*, d belongs to Zp*. Now, domain for H1 would be:

H1: {0, 1}* x G1 -> G1

2) H2=H(t, f), where f=e(g1, g2). The domain of H2 would be:

H2: {0, 1}* x GT ->Zp*

3) H3=H(f). The domain of H3 would be:

H3: G1 x G2 -> GT

4) H4=H(g2^s), where s belongs to Zp*. The domain of H4 would be:

H4: G2 -> G2.

5) Can I use {0, 1}* and Zp* interchangeable?

It would be nice, if some one could help me.

Thanks.

Many references do define them, but I require the key differences between them and how they can be practiced.

1)Asymptotically the cost of finite field multiplication is same as field squaring. How to measure their ratio accurately on a machine?

2)Similarly, the asymptotic cost of finite field multiplication is same as field inversion. So how to measure their ratio accurately on a machine?

I performed 2 level 2D DWT on the cover image (gray) and performed 1 level 2D DWT on the secret image. On the lowest LL2 subband of cover I hide the LL1 subband of message using an encryption algorithm but I am having problem performing the inverse DWT operation. After the inverse operation I am not getting the proper image back. I am getting an image lost in noise. So how can I get proper recovered image?

I am new in Steganalysis side. Can anyone guide me implementation of RS analysis (Fridrich 2001), paper implementation, or have any reference code?

I am planning to do a Master's project on Forensics (actually anti forensics) and I have chosen steganography as my area of interest.

I would like to focus on how steganography has related to forensics over time and whether it can be used together with cryptography to enhance information hiding and obscuring. I would like to hear from anyone who has done (or is currently doing) research in this area to share information.

Which one is better among public key cryptography key exchange and Zero-knowledge password proof? Which one is more popular, powerful or useful? Which one is used more in daily life or products which are used quite often? Can you give me some good examples?

steganalysis is sicence that detect secret data that hided in cover medias. so I am searching about softwares abouth this method, specially about steganalysis methods in image cover. Can anyone help me?

In claim 3 how prove and what symbols in this claim mean?

in H1 list w refer to word and h refer to hash of w and c refer to random coin but what about "a"?

How can I implement Elliptic curve through Fingerprint after finding its minute poits and also ECC parameter ?

I have an array that contains all Minuate points of Fingerprint.With the help of that array I want to generate ECC curve

Kindly help me

I am doing a research on prediction analysis of encrypted data. And would like to find out what latest developments (algorithms, tools, methods, practical applications etc.) have been done in this area.

A series of my compounds based on triazoles seem to like to crystallise from hot MeCN but they do in very thin needles forming kind of pompoms.

Anyone have any tips? Tried vapor diffusion, layering and so on with several solvents but the best still seems to be crystallisation from MeCN.

Cheers

Let S = {n.1, n.2, ..., n.n} = n{1,2,...,n}. A (cycliclly) permutation of S has the property:

each ordered pair of S^2 occurs in the permutation with distance 1 (adjacent) exactly once; and occurs with distance 2 exactly once.

For detail: Suppose the permutation is s_0, s_1, s_2, ..., s_{n^2-1}, then

{(s_{i}, s_{i+1}) : i=0, 1, ..., n^2-2}U{(s_{n^2-1},s_0)}=S^2;

{(s_{i}, s_{i+2}) : i=0, 1, ..., n^2-3}U{(s_{n^2-2},s_0), (s_{n^2-1, s_1})}=S^2.

I think the permutation with the above property does not exist, but I don't know how to prove it.

IBE was first introduced by Adi Shamir on 1984 to provide easier method of public key encryption. Ever since, it has always been an area of research. What are its vulnerabilities? What are the design problems of establishing such a system? Why has it been an open problem for the last 30 years?

Homomorphic encryption based on standard LWE.

I think we prefer Public-key Cryptography, because of its computationally hardness, over Private-key Cryptography. Is this the only reason or?

I'd like to research on the available cryptanalysis tools for algorithms such as AES, DES, RSA, RC4, Blowfish and the like.

"Intelligence agencies hire lots of mathematicians, but would-be employees must realise that their work is misused to snoop on everyone, says Tom Leinster"

New Scientist has published an article recently, where Tom Leinster asks mathematicians to stay away from supporting NSA, CIA, GCHQ, (former) KGB and all the other organizations that spy on us. I even don't know the name of their Chinese colleagues' organization.

What are your thoughts on this?

Currently I am working on my project work related to Cobalt Oxides systems (CoO and Co3O4). I required surface energies values for different planes (111,110,100) for my project work.

Everyone seems to quote 'market cap' (price*total volume) but this seems to be of pretty limited value, particularly if you want to have a measure of the relative utility or use of a cryptocurrency. Can anyone suggest some alternative metrics? It seems that there's an entire field here yet to be developed.

Suppose we are considering only confidentiality and for now just ignoring the active attacks. So we encrypt the email with the secret key generated by online trusted third party and then send both the ticket and encrypted email to the receiver. By ignoring the problems and drawbacks of the online trusted third party. So what are the problems with this mechanism? Also for each email/session we are using a new key.

The correlation attack is one of the most important attacks that attacks stream cipher. Can someone share an illustrative example of a simple application process for this attack.

Any working example of a projection map to any two groups (two cyclic groups)?

We have a theorem that if the the connection polynomial of LFSR is primitive, then the period of the output keystream will be maximal i.e 2^n - 1.

Why are 2^48 false alarms expected in double Des (Man in Middle attack)?

I have been mainly using Shoup's NTL library, openssl, and Stanford's PBC library for most of my implementation of research work. All three of them are quite easy to use and stable. I would like to know what other libraries you use and your experience with them.

It is very difficult to know the exact origins of mathematics. I would like to know about new number systems which are under research. New number systems can be used for cryptography.

In this question G is an cyclic additive group, Zn* is the set of integers from 1 to (n-1) and {0, 1} is the message passed to hash function in elliptic-curve cryptography.

This hash function have call value as: H1(message,(x1,y1),(x2,y2))---> Zn*

where Zn*={1,2,3,4,.........,n-1} and n is a prime number. What are the methods to perform this operation?

I want to encrypt the image of thumb which will be taken from the thumb scanner and store in database.

Can anyone suggest a better cryptographic code in matlab for performing this process?

This question ocurred to me after reading the attached news article and the main paper reference for it:

In this paper, there is a claim of practicality of quantum cryptography, but the paper only mentions a data rate for the key of about 6kbit/s (for a distance of 90 km). Although there are already some holes in the computer science component (dealing with multiple hops, switching, security of the cryptographic mechanism itself), I'm really wondering what kind of requirements there are. As a computer scientist, this subfield of cryptography and the physics components are not in my core interest field, so I was hoping to gain some insight from the researchgate community.

Is the practicality claim overstated, or should I start brushing up on my qubits?