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2 votes

Is it possible to use Diffie-Hellman protocol for symmetric group?

In the question, a symmetric group is the set $S_n$ of permutations of $n$ things. $S_n$ has $n!$ elements. It's internal law noted  $\circ$  is function composition: $w=u\circ v$ is defined by $w(i)=...
fgrieu's user avatar
  • 141k
0 votes

Where can I download a database of RSA keys?

There is a 900,000 domain-key database at registry.prove.email, that no one to my knowledge has run batch-gcd on yet. There may be some reused keys between websites however, so total unique keys may ...
John Targaryen's user avatar
2 votes

Key Exhaustion Risks in Symmetric and Asymmetric Cryptography

This problem is closely related to tightly-secure encryption schemes in the asymmetric encryption areas (or more precisely in multi-challenge security). This is because classical security notions like ...
CQian's user avatar
  • 21
4 votes
Accepted

Key Exhaustion Risks in Symmetric and Asymmetric Cryptography

Such a restriction would no make sense in asymmetric encryption schemes where there is a public key value made freely available to all, including the adversary. This gives the adversary the power to ...
Daniel S's user avatar
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0 votes

Trouble detecting cyclic group order crossovers in SECP256K1

I'm not really answering the question but I think the flaw in your reasoning is that there is no definition of crossing over, hence you won't be able to detect whether a point crossed over or not. It ...
Ruggero's user avatar
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0 votes

Is it possible to homomorphically evaluate an encryption circuit?

Maybe you can use programmable bootstrapping (PBS) to solve this issue, it is a way to evaluate an arbitrary function during bootstrapping. e.g., $PBS(Enc(M, K_1), f) = Enc(f(M), K_1)$. Inyour ...
lamba's user avatar
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2 votes

How to know if an ECC public key is y or -y

Straightening the question's vocabulary: on secp256k1 every point $Q$ has an opposite point (or additive inverse point) noted $-Q$. For the $n-1$ points $Q$, the opposite $Q'=-Q$ of $Q$ has the ...
fgrieu's user avatar
  • 141k
1 vote

Creating multiple "public" keys from one private key

It sounds like you are talking about key derivation, for example Hmac-based key derivation (HKDF). You can derive a private key from a known (private) seed or from another private key, creating a ...
Rohinton Collins's user avatar
3 votes

Is it possible to generate an elliptic curve (with the hard discrete logarithm problem) by iterating only a finite field, but not its $j$-invariant?

Yes, this is straightforward enough. Write down you elliptic curve with coefficients in $\mathbb Q$. For any $p$ you can then use the same equation with the coefficients interpreted as elements of $\...
Daniel S's user avatar
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1 vote
Accepted

Is concatenation of secure encryptions secure?

Yes, generally the encryption with separate unrelated public keys of a plaintext message is considered secure. This is true even if you use the same scheme, but it is fine to choose other secure ...
Maarten Bodewes's user avatar
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