# Questions tagged [implementation]

Implementing a cipher or protocol is the process of taking it from its mathematical or algorithmic description and producing a working version, often in computer software or hardware. This tag should be used for any question discussing the various potential considerations and pitfalls of this process, for example padding.

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### What efficiency can we expect from an average consumer computer for the RSA algorithm?

I am trying to implement the RSA algorithm using the C language, for learning purpose. I was wondering how much time should we expect it to take for encrypting a message of size 1024/2048/4096bits on ...
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### Problem with efficiency of projective coordinates in Elliptic Curve arithmetic

Ok sort of long post incoming. Will go slow to make it as clear as possible I'm trying to build a C library for Elliptic Curve Arithmetic. Since the idea is to learn from the process, I decided to ...
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### Has garbage-collection been used for side-channel attacks?

I'm thinking of cryptographic implementations on garbage-collected (gc) languages/runtimes and that the gc process can be potentially dangerous for an implementation even if the implementation has the ...
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### How do you securely implement a finite field?

I'm not sure if this question belongs here or to StackOverflow. Please flag it if not. I'm trying to implement a standalone library for finite field arithmetic of prime and prime power order as a way ...
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### Why is the constant in Montgomery Curve code 121665 instead of 486662 in the formula?

In the Montgomery Curve $y^2=x^3+486662x^2+x$, $A=486662$. So, why when applying its code in Python or another programming language, $A=121665$? ...
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### Is an if-else calling same function(s) vulnerable to side channel attacks

If I have a function f(x, y) and g(x, y) and f and g a are constant time, is the following code vulnerable to side channel ...
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### Do you know any library for implementing lattice-based schemes? [closed]

Good afternoon! I'm trying to write a code for a lattice based scheme (based on the SIS problem). I'm looking for a library that may help me in this task without taking care of the implementation of ...
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### Radix-2^51 arithmetic of edwards25519

The Golang implementation of edwards25519 (https://tip.golang.org/src/crypto/internal/edwards25519/field/fe.go) uses radix-251 representation. The description in section 3.2 in https://dl.acm.org/doi/...
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### Homomorphic Encryption and Conjugation

In the implementation of HEAAN, they have implemented the conjugate function. It computes conjugate of a polynomial. Effectively they have reverted the positions of the coefficients and negated their ...
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### Can attackers see the values I pass on to OpenSSL API functions?

Respected community, I am using the OpenSSL API's, especially libcrypto and libssl and I am really depressed, thinking about ...
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### Operands size in RSA Cryptography (C language)

I am trying to implement the RSA cryptography algorithm using C language. I am not sure of the size that each operand should have. Let me explain: RSA requires to generate two huge prime numbers p and ...
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### Browser javascript: TLS sequence number authentication

I am implementing TLS (or something like it perhaps) because the browser doesn't seem to provide a direct client-script interface to TLS. The browser provides a ...
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### Good libraries for lattice-crypto [closed]

I'm searching good libraries to manipulate lattice tools to do cryptography. I'm mainly interested by C/C++. But I'm also interested if it is in python.
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### Make linkable ring signatures shorter?

I need a way to make the signatures shorter, currently with a ring size of 1000 members I get a signature size of 34000 bytes, this is too big for me I need a way to make it smaller. I tried ...
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### What are the performance reasons behind "xor-a-rotated-sum" instead of "add-a-rotated-xor" in Salsa20?

I'm currently reading the specification of Salsa20 (link). DJB on whether he chooses "xor-a-rotated-sum" instead of "add-a-rotated-xor" states the following : Should there be ...
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### Is gcc's stack canary cryptographically secured? Does stack canary in general has to be cryptographically secured?

I want to ask 2 questions: Is GCC's stack canary cryptographically secured? Does stack canary in general has to be cryptographically secured?
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### Accelerating Syndrome-Trellis Codes (STC) for GPU [closed]

From the literature, STC seems to be the current state-of-the-art for the coding part of steganography. From the description of the method, it appears to me it could be parallelized for GPU. Does ...
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### Faster linkable ring signatures libraries

I need a fast linkable ring signatures library, something that is O(log(n)) and n is the ring size. I read a few papers about these kinds of schemes but I didnt find any implementations of them. Here ...
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### Can reinforcement learning speed up modular multiplication?

In Discovering faster matrix multiplication algorithms with reinforcement learning (Nature, 2022; lightweight intro), the authors used reinforcement learning (an artificial intelligence technique) to ...
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### Universal Dynamic Accumulators : all parties know keys p and q. Is the original set needed to validate set membership and non membership?

I read this paper on RSA cryptographic accumulators have some questions on a few points : "Universal Accumulators with Efficient Nonmembership Proofs" https://www.cs.purdue.edu/homes/ninghui/...