# Questions tagged [verifiable-random-function]

A verifiable random function is a public-key cryptosystem serving like a pseudorandom function under a secret key, with the additional characteristic that outputs are verifiable under the corresponding public key.

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### Is it safe to reuse the same scalar when doing direct scalar multiplication on Koblitz curves?

Let $s$ be a private key and $k=intAsScalar(s)$. Finding $s$ from $P_k=[k]G$ involves solving the Elliptic curves discrete logarithm problem. But what if the same $k$ is also used for performing 1 or ...
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### How could a 1024‒bits RSA modulus be most economically factored within months today?

Of course this is a question with an answer that is due to evolve. A 2002 paper about TWIRL stated that the cost would be around 10M\$and an other 10M\$ to manufacture the device. A later 2007 paper ...
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### Is it possible to perform reverse rsa encryption ? (using the public key for decrypting and the private key for encrypting)

Simple question, but I couldn’t find an answer as I know about signing but don’t want it. The aim would be to encrypt someone’s bet parameter as a short message using the private key and use the ...
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### Question about the Residual Pseudorandomness property in Verifiable Random Function paper, written by Micali, Rabin, Vadhan, in 1998

I am reading a paper named Verifiable Random Function, written by Micali, Rabin, Vadhan in 1998. In Residual Pseudo randomness propoerty of a VRF, it is written that If T runs for at most s(k) steps, ...
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### How can 4 users generate a provable fair random number?

The past few weeks I have been trying to solve a difficult problem. I have asked some cryptography experts but unfortunately they had no clue on how to solve the problem. The situation is as follows, ...
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### Proof-of-Randomness with an EC Public Key

I will be using a tRNG to generate EC keypairs on a Secure Integrated Controller. I need to demonstrate I, the issuer, can not know the private key without colluding with the user to obtain it, even ...
1 vote
194 views

### Is there a scheme to enforce a random seed without leaking the seed?

End-to-end encrypted web services (like cryptpad) often include a 128-bit seed in the hash part of the URL (that is not sent to the server), to derive both an identifier that is sent to the server, ...
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### Using system time in nano-seconds as source of entropy in a smart contract

I am working on a smart-contract to be deployed on ETH chain. I am using an oracle(not the company!) system to get the information from off-chain (outside of the blockchain). Basically, we can think ...
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### Commit the output of verifiable random functions

The problem setting is as follows. Suppose there exists a public input $x$ and the prover evaluates $y \gets VRF_{sk}(x)$, but the prover does not wish to reveal the output $y$. My question is would ...
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### How are the keys used in cryptography generated?

It seems there are keys everywhere in cryptography. From things like HMAC to encryption (both asymmetric and symmetric). The bit I do not totally understand now is how are cryptographic keys generated?...
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### A source of randomness that anyone can independently, conveniently and robustly access?

Does there exist a source of randomness that anyone in the world can independently, conveniently and robustly access? For example, the 10th decimal place of the temperature in Mexico City is ...
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### Can we instantiate VRF without using pairing?

As my survey, most of(I am not sure if it is "all") the constructions of VRF are instantiated with the use of pairing. Can we construct a VRF without using pairing?
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### Range proofs and Groth-Sahai PPEs

I'm looking for a set of pairing product equations (ala Groth-Sahai) which allow a prover to prove that the output of a VRF is in a specific range. In the E-cash system in [BCKL] there is a ...
1 vote
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### Group Verifiable Random Function

Is there any algorithm that allows to set up a VRF (Verifiable Random Function) from a set of Keypairs such that the knowledge of one private key and all the other public keys is enough to compute the ...
683 views

### What is the main difference between Unique signature and Verifiable Random Function?

The output of VRF contains two parts, the first is the output of the VRF hashing and the second is the proof of correctness. In a unique signature scheme, the signature also contains two parts which ...
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### Can we use BLS as a VRF?

Intuitively, it seems that the hash of a BLS signature could be used as a VRF as well. In a nutshell, BLS-Signature is the VRF output and the verification first ...
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### Does this description of verifiable random functions seem accurate?

I've been thinking about verifiable random functions recently due to my interest in sortition (random selection of political officials). I wrote up this little paragraph below, and I'm wondering: Does ...
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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 ...
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### Can Verifiable Random Functions be used to pick a random node from a pool?

Let's say that I have a decentralized system and I have a list of nodes published on a public log like a blockchain. I want a node A to be able to connect to ...
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### What is the difference between signatures and VRF?

For example we have asymmetric signature scheme(RSA or ECC based) and VRF(also can be RSA/ECC based), both of them can be verified using public key of the signer/hasher and also are unique for each ...
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