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.
Questions tagged [implementation]
578 questions
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How is the Swiss post e-voting system supposed to work, and how was it wrong?
I read that the Swiss post had an e-voting solution developed, made it possible to obtain the source code for review, and that vulnerabilities were found.
Apparently we are not talking about the inherent and well-known issues of e-voting: it can't…
fgrieu
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5 answers
In RSA, how does the CPU deal with this huge modulus (8192 bits)?
Whilst I understand how the RSA algorithm works, I don't understand how the CPU operates when it needs to use the mod function with a huge number $n$, for example.
$n = 8192$ bits;
$c = m^e \mod n$;
In essence my question is how does the CPU deal…
artless-person
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31
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What is a white-box implementation of a cryptographic algorithm?
What is a white-box implementation?
Does a white-box implementation have specific properties?
ir01
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30
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3 answers
What is the recommended number of iterations for Argon2?
I've recompiled my operating system ("LionBSD" based on FreeBSD) to use Argon2i as the default password hashing algorithm in crypt/libcrypt.
I'm wondering what the recommended number of iterations would be?
As an example, OpenBSD uses 8 iterations…
fizk
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28
votes
3 answers
How is bitslicing faster?
I have read a paper on Bit Slicing and Lightweight crypto but cannot understand how bitslicing makes encryption scheme faster.
Please can someone explain with an example exactly how bit slicing makes the code faster (even a single xor example will…
ishaan arora
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27
votes
7 answers
Why is SRP not widely used?
SRP seems to be a very good password authentication protocol, compared to any other things used now. So why is there no popular implementations, or even no working secure implementations?
I tried to set up TLS-SRP protocol, but it haven't worked…
Smit Johnth
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27
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5 answers
Timing-Safety in JVM-Languages
How is it possible to write timing-safe code in JVM-languages (Java, Scala, Clojure...)?
Is it possible to make libraries like BouncyCastle safe against timing-attacks?
I know that even in C it is very hard to get those things right – and in C you…
K. Biermann
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23
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3 answers
Known methods for constant time (table-free) AES implementation using 'standard' operations?
There are several known methods for implementing AES in constant time using SIMD operations, mostly based around fast byte shuffling (for instance Hamburg and Kasper/Schwabe). Are there any similar approaches that allow a constant-time AES to be…
Jack Lloyd
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22
votes
6 answers
Types of Cryptography for a 4-8 bit microcontroller
This is more of a research question.
I was wondering what types of crypto algorithms would work best on a small 4-8 bit micro controller. I recently read a paper called Security Considerations for 802.15.4 Networks and was wondering if anyone out…
Jim
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How fast can a SHA-256 implementation go?
I'm looking for high-speed SHA-256 implementations, and specifically, ones with low latency; that is, the time between when you submit the message block, and when the output (or internal state) is produced.
I've googled it, and the fastest I've…
poncho
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20
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4 answers
Is there a standard for OpenSSL-interoperable AES encryption?
Many AES-encrypted things (files, strings, database entries, etc.) start with "Salted__" ("U2FsdGVkX1" in base64).
I hear it's some sort of OpenSSL interoperability thing: a b c.
Is there some standard reference somewhere (perhaps an RFC?) that…
David Cary
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20
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3 answers
Cryptanalysis to reverse engineer a hash?
I understand this may not be the best place to ask a question like this, but I believe that this community may be the best/only place I can ask such a question.
I have inputs and outputs from an in-house hash developed years ago and the developer…
user316
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19
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4 answers
Should I delete cryptographic data from memory?
When dealing with cryptographic data, is there a chance that attacker recovers portion of data I used in my program? Should I try to delete every bit of keys and encrypted data that I used, overwrite it with zeroes?
And one extra, how is situation…
user1687327
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19
votes
3 answers
Webcam random number generator
I have a question about random number generators.
I have read from a real random number generator, based on a webcam ("randcam"). My problem is, that I do not really understand how the generation of the random numbers works. Has anyone heard of…
Simon Rühle
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19
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1 answer
Edwards / Montgomery ECC with Weierstrass Implementation?
So let's assume I want to perform Ed448 or Ed25519 digital signatures or want to perform a DH key-exchange. Assume further that those curves (Curve448 or Curve25519) are required.
But the problem is, that I have only a constrained device given,…
SEJPM
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