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### RSA: Is it a security risk if an attacker knows the length of the values of P and Q?

Is it a security risk - or perhaps, how big of a security risk is it - if an attacker knows the length of the values of P and Q used when deriving a value for the parameter N in the RSA encryption ...
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### Adi Shamir's secret database of all primes

I was going through these presentation slides (PDF) on Crypto 2013. It summarizes the paper, Factoring RSA keys from certiﬁed smart cards: Coppersmith in the wild. In the last slide, it was ...
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### Do we want to allow/Have we allowed parallelization (e.g GPU programming) to enter the cryptographic field? What are the consequences?

With the term GPU programming, I'm referring to highly parallelizable computing in general. Lastly, I have built a bit of a background in cryptography. So I have started to wonder if/where GPU ...
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### How does SSH generate keys for RSA algorithm?

As far as I understood, the core of the RSA algorithm is to have 2 (large) primes ‘p’ and ‘q’, so that ‘n=pq’. Then ‘n’ is the public key, and ‘p’ the private one. The security comes from the fact ...
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### Where are TRNGs an absolute need?

Are there situations currently where a PRNG just will not do? Are there current situations where only a TRNG will be useful? What about if someone uses a cryptographically secure PRNG? What is the ...
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### Can Big Data together with deep neural networks attack RSA by affording the vast calculation of prime multiplications in advance?

This is a spin-off from Can Big Data attack RSA by just calculating many prime multiplications in advance? [duplicate]. Intro I am somewhat new to cryptography. Repeating the basics of RSA from How ...
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### Disclosure of Catastrophic Cryptanalytic Breakthroughs

An efficient algorithm for factoring would be a major mathematical achievement giving the person who discovered it anstant fame. About two years ago, C. P. Schnorr claimed such a breakthrough but it ...
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### Prime Factorization in RSA always leads to the product of two primes?

Lets prime factorize $30$: $$30 = 3 \cdot 10 = 3 \cdot 2 \cdot 5$$ We see that the number $30$ is a product of $3$ primes. But in RSA, when factorizing huge numbers, we always seem to only get two ...
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### Randomness extractors from Bourgain’s breakthrough- applications?

Some exciting progress to pure mathematics is due to Bourgain Springer - Multilinear Exponential Sums in Prime Fields Under Optimal Entropy Condition on the Sources with applications to randomness ...
1 vote
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### Using first, say, 50 letters from a public key as user identifier?

I am making a messaging system where users are identified by their public keys. It doesn't matter which friendly username they have, so I'm not going to prompt them to choose one. Each user will ...
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1 vote
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### With composite $n_1$ = $p_1q_1$, and a separate $n_2 = p_1q_2$, can the primes be calculated more efficiently than factorization?

Supposing that the (3 total) primes are kept secret? Does the reuse of $p_1$ allow an attacker to compromise $n_1$ and $n_2$ if the attacker guesses that both were generated with a shared prime ...
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Is there any way to derive the RSA private key from another RSA private key? Let's say I have a base RSA key $(P, Q)$ (both prime), and then use some salt and an algorithm that creates a new primes, e....