A reference request is a request to be provided with a source from documentation, official papers, and specs related to one or more specific algorithms or cryptographic procedures. Open ended literature recommendation requests are off topic!

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9
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2answers
467 views

How to do a literature search

How do I do a literature search of the research literature on cryptography? Assume there's some topic in cryptography I'd like to learn more about; how do I search the cryptographic research ...
4
votes
1answer
407 views

Is knowing the private key of RSA equivalent to the factorization of $N$?

Given the RSA modulus $N$ the fastest method to factor it is of sub-exponent order. But, now if I know the private key $d$ of RSA, does that mean I can factor $N$ efficiently?. It intuitively seems ...
10
votes
0answers
707 views

Who first published the interest of more than two prime factors in RSA?

Multi-prime RSA is now a well known technique (described here): it uses $k>2$ distinct secret prime factors in the public RSA modulus, with the advantage that, using the CRT, we can gain a speed ...
4
votes
1answer
2k views

What is “Implicit Authentication”?

What is “Implicit Authentication” in the context of authentication methods? I searched the Web but could not find any article that describes this. If anyone can describe it, that would be a great ...
9
votes
3answers
1k views

Elliptic Curves of different forms

Looking at http://safecurves.cr.yp.to/ to find a safe curve, I find that most curves described here are of a different form from that generally used. In Bouncy Castle, for example, ...
14
votes
3answers
2k views

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 ...
11
votes
7answers
2k views

How exactly is “true randomness” defined in the realms of cryptography?

Especially in relation to stream ciphers, I frequently read about (sometimes theoretical, sometimes practical) attacks that are able to "distinguish a ciphertext from a truly random stream". What's ...
9
votes
2answers
1k views

When using Curve25519, why does the private key always have a fixed bit at 2^254?

When using Curve25519, the private key always seems to have a fixed bit set at position 2^254. Why is that? Is there any good reason to use a fixed positioned most-significant-bit in the private key?
6
votes
1answer
1k views

Description of signatures with message recovery (as in ISO/IEC 9796-2 and EMV Signatures)

I'd like to get an overview of how the signatures with message recovery work, especially in case EMV and other smart card systems. Is there a nice overview available without being required to read the ...
5
votes
1answer
112 views

Are there any long term RC4 bias based exploits?

The RC4 cipher possibly exhibits low level bias in it's long run PRNG keystream. I'm specifically excluding short term bias attacks which I'm defining as outputs < 1024 bytes. Are there any real ...
1
vote
1answer
196 views

Choosing primes in the Paillier cryptosystem

In the first step of key generation phase in Paillier cryptosystem given here. It's given that $$\operatorname{length}(p) = \operatorname{length}(q) ) \implies \operatorname{gcd}(pq,(p-1)(q-1))=1$$ ...
3
votes
2answers
309 views

What is the use case for XOF functions (i.e. SHAKE128/256)?

FIPS 202 defines 2 functions: SHAKE128 SHAKE256 As extendable-output functions (XOFs) that can have variable output length. But in Appendix A.2 marks: it is possible to use an XOF as a hash ...
28
votes
1answer
4k views

Examples of modern, widely used ciphers that suddenly fell?

RC4 and GOST are two major ciphers (defined as being widely used to encrypt large amounts of data) that fell to cryptanalysis (relatively) suddenly. The first becoming totally broken and the second ...
12
votes
4answers
7k views

Is secp256r1 more secure than secp256k1?

Curves secp256r1 and secp256k1 are both examples of two elliptic curves used in various asymmetric cryptography. Googling for these shows most of the top results are Bitcoin related. I've heard the ...
21
votes
1answer
1k views

Proof for the SHA3 claim that 256 bit security is “post-quantum sufficient”?

On page 14 of "Keccak and the SHA-3 Standardization" (February 6, 2013) it says: Instantiation of a sponge function the permutation KECCAK-f 7 permutations: b → {25,50,100,200,400,800,...
10
votes
1answer
429 views

Status of Algebraic Eraser key exchange?

Algebraic Eraser™ is a relatively new asymmetric key agreement protocol (also designated the Colored Burau Key Agreement Protocol), based on a simultaneous conjugacy search problem in a braid ...
6
votes
3answers
892 views

Is the logic for how the enigma machine worked documented somewhere?

I know that there is a formula to calculate the result of any input but is the logic of how the machine actually worked documented? I have seen schematics for the circuitry and even a how to make ...
1
vote
3answers
155 views

Salsa20-GCM composition secure?

AES-GCM seems to be used by everyone but I never seen even one post about Salsa20-GCM. Is it secure? Wikipedia mentions that GCM ...
6
votes
1answer
815 views

Keccak padding implementation, and bit ordering

I am trying to implement Keccak in Java for my school work. And I am getting stuck in two places: On the summary page the padding is shown as P = M || 0x01 || 0x00 || … || 0x00 P = P xor (...
5
votes
1answer
681 views

Families of public/private keys in elliptic curve cryptography

I'm looking for a related key scheme for elliptic curve cryptography. The basic idea would be that there would be a master public key and a master private key. From the master public key, you could ...
4
votes
2answers
103 views

Are there simpler FHE methods than Craig Gentry's original paper?

Craig Gentry's 2010 paper on FHE is very cool, and I'm planning on implementing a basic proof of concept FHE. I was wondering though, are there any simpler methods that have been discovered since ...
4
votes
4answers
577 views

Why $n=pq$ with $p=2p'+1$ and $q=2q'+1$ instead of just $n=p'q'$ for RSA crypto?

For RSA cryptography, we know that the modulo $n$ is a product of two big prime numbers(say $p$ and $q$). However, in some documents I see an extension of $p=2p'+1$ and $q=2q'+1$ with $q'$ and $p'$ ...
4
votes
4answers
2k views

Pseudocode for constant time modular exponentiation

I'm looking to implement modular exponentiation (for RSA) in constant time, but most of the examples I've found are more mathematical descriptions of the operations. Are there any references with ...
3
votes
1answer
202 views

Which public key encryption scheme is re-randomizable? How can I re-randomize an encryption scheme?

Which public key encryption scheme is re-randomizable? Is there any library for re-randomizable encryption scheme? If not, how can I re-randomize a given public key encryption scheme? I cannot find ...
2
votes
1answer
277 views

Short length asymmetric encryption?

I want to send out short messages to the world which listeners could verify to be send from me. The way this is usually done is to encrypt the message with a private key where the readers decrypt it ...
2
votes
2answers
2k views

Digital Signature using symmetric key cryptography

Generally digital signature is a public key cryptography concept.But it needs high overhead. So is there any publication or link available where 'digital signature using symmetric key' has been ...
7
votes
1answer
228 views

Is there any general description language for block ciphers?

In page 9 (16 in the PDF) of Final report of European project IST-1999-12324 (NESSIE), it is mentioned that: The NESSIE project is also developing a new generic tool to analyze block ciphers ...
6
votes
1answer
289 views

Difference between “ECDH with cofactor key” and “ECDH without cofactor key”?

I need to use “ECDH with a cofactor key” for generating symmetric key. I have a fair idea on how ECDH works, but I don’t understand the cofactor part. What is the difference between ”ECDH with a co-...
6
votes
1answer
1k views

How much entropy is lost via hashing when you add known or low entropy data?

(I updated the title, as I think there was some confusion as to the question) Here's the question: For example, if I have a bit stream that is 64K bytes long and there is about 16 *8 bits worth of ...
5
votes
4answers
1k views

Security proofs for CBC mode

I'm looking for different approaches to proofs for the security of CBC mode encryption. What are the best sources of information about this subject?
3
votes
2answers
393 views

Security issues of a MAC-then-Encrypt-then-MAC approach?

Encrypt-then-MAC does provide ciphertext integrity, but no plaintext integrity. With MAC-then-Encrypt it’s the other way around: Plaintext integrity but no ciphertext integrity. What comes to mind is ...
3
votes
3answers
159 views

The meaning of “scheme”

This question is a bit different from other questions here, but I think it is suitable to correctly understand the terminology of cryptography. Consider the following two sets of terms: Encryption ...
3
votes
1answer
134 views

Where is SRP-Z from?

The Stanford license for SRP says: Broader use of the SRP authentication technology, such as variants incorporating the use of an explicit server secret (SRP-Z), may require a license; Yet ...
3
votes
1answer
54 views

How are the IVs of SHA512/256 and SHA512/224 calculated?

This seems odd to me, because there are a lot of resources out there saying that the initializer values of SHA512 and SHA384 are the first 64 bits of the fractional parts of the square roots of prime ...
2
votes
0answers
369 views

Elliptic Curve based blind signature implementation

I want to use Elliptic Curve based blind signature scheme for my research. There is no proper implementation of ECC-based blind signatures. Can someone describe to me which things I need to follow ...
2
votes
1answer
2k views

Certificate signature with SHA-1 and RSA: where do 1888 bits come from?

Plenty of X.509 Certificates use "PKCS#1 SHA1 with RSA encryption" as the Certificate Signature Algorithm for generating a 2048-bit signature. The SHA-1 hash function generates a hash value of 160 ...
0
votes
2answers
233 views

DES hardware implementation of substitution lookup table [ ReWorked ]

I'm a crypto enthusiastic and student of cryptography. I'm developing a project with other students titled "A hardware implementation of a DES cryptography for educational purposes", our idea was to ...
-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 ...