Cryptography Stack Exchange
Cryptography Stack Exchange

Questions tagged [key-distribution]

In symmetric-key cryptography, both parties must possess a secret key that they must exchange prior to using any encryption. Distribution of secret keys is problematic: it involves face-to-face meetings, the use of a trusted courier, or sending the key through an existing encryption channel.

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What makes Quantum Cryptography secure?

This is my current understanding of how Quantum Cryptography works: (The first bit is Quantum Key Distribution) Alice sends a beam of photons to Bob through a quantum channel such as an optical fiber. Each of these photons represent a bit of…
lal lal
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How is the key shared in symmetric key cryptography?

Symmetric key cryptography is an encryption system in which the sender and receiver of a message share a single, common key that is used to encrypt and decrypt the message. Is the key public or it is secret? How can the sender and the receiver both…
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Key Exchange & key Distribution in symmetric key cryptography

I want to know whether there is a difference between key exchange & key distribution in private key cryptography as well as public key cryptography? or is it the same term?
Smita Chaudhari
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Is E91 safer than BBM92?

I would like to compare the security of these two QKD protocols which both use entangled photons that are distributed between the users Alice and Bob. In the case of E91, the photon is measured randomly in 3 different bases which allows to violate a…
Mechanix
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What are the current known weaknesses/attacks on quantum key distribution?

I am writing a paper on the implementation of QKD in the future. I want to know if there are any viable attacks on the BB84 protocol or QKD in general? I know of the Photon Number Splitting attack or spectroscopy in the case of diode manufacturing…
Kenneth
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Proof of correct construction of a private key in distributed cryptography

In an exponential ElGamal encryption scheme where the key generation is done in a distributed way among $n$ trustees we have that each trustee $i$ (where $1 \leq i \leq n$): Selects a private key share $x_i \in \mathbb{Z}_q^{\star}$. Computes a…
LRM
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Understanding Quantum Key Distribution

I have watched dozens of videos on YouTube talking about quantum cryptography and how the BB84 algorithm works. However, none of them bothered to explain how the quantum key exchange process works in detail; that is, for newbies like me. Thus I…
ecdhe
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Why in one time pad must the key distribution to be truly random

One time pad required a truly random key. Why canwt it be a psudo-random key? For example, if the key distribution is that for each bit the probability to get 1 is 0.6 and the probability to get 0 is 0.4, and the eavesdropper knows it, how can he…
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How are one-time pads distributed?

It seems that OTP encryption is unbreakable. I have read some articles (Wikipedia, Blogpost, etc.), but I could not find any information about how they are used. If I wanted to create a messenger service, how would I distribute the OTP keys? Both…
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Public Keys on Social Media

Is there any problem with using social media (i.e. Facebook) as a directory of public keys? For example, couldn't Alice put a note containing $(g^a \bmod p, g, p)$ on her Facebook page so she could receive email attachments which have been encrypted…
Ken
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How to generate Multiple Encryption Keys for use in RSA polymorphic multiplication

I am a long time scroller, first time poster in the crypto stack. I've recently been finding myself leaving the realm of mainstream/standard crypto (imo that consists of symmetric/asymmetric encryption, some ciphers and one way hash functions ect).…
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Difference between group key agreement, group key sharing, group key distribution and group key establishement

I am currently doing a survey on group key, and throughout my readings, I stumbled on these different terms: Group Key agreement, Group key Sharing, Group key distribution, and Group key establishment. My question is the following: is there a…
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Struggling to understand Perfect Forward Secrecy

From the definition on Wikipedia: In cryptography, forward secrecy (FS), also known as perfect forward secrecy (PFS), is a feature of specific key agreement protocols that gives assurances that session keys will not be compromised even if the…
pfsconfusor
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Reduction from integer factoring to computational Diffie Hellman

The computational Diffie Hellman (CDH) problem for ${\mathbb{Z}}^*_p$ is given a prime $p$, a generator $g$ of ${\mathbb{Z}}^*_p$, and a pair $(g^i, g^j)$ to compute $g^{ij}$. The value $g$ is called the base. In cryptographic protocols the base is…
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Does an EC signature preserve entropy?

Assume I have a perfect source of entropy, which is unknown to me, and is used to generate a private key (also unknown to me, but usable). If I make a signature with this unknown private key on a constant piece of data (e.g. hash('foo')) and then…
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