Questions tagged [homomorphic-encryption]
Cryptosystems which support computation on encrypted data. They might be partially homomorphic (support for one operation such as + or *) or they might be fully homomorphic (any sequence of + and *).
952 questions
2 votes
1 answer
66 views
FHE - CKKS: Why additional modulus reduction is needed in rescale instead of naive division by scaling factor and rounding
I’m currently studying FHE, specifically CKKS, as part of a seminar. I understand most of it, but I’m still stumbling over one issue that I haven’t found a clear explanation for online. Here’s the ...
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1 vote
1 answer
67 views
Is the complexity of sieve algorithms for SVP really $2^{c n}$ for attacks on CKKS?
I know that Sieve Algorithms are good attacks against CKKS Encryption Techniques. I want to know the exact expression of the complexity of the Sieve Algorithm attacks, according to Miklós Ajtai, Ravi ...
- 31
4 votes
0 answers
54 views
Why does the result of modulo switch reduces the size of modulo?
I am studying the basics of the CKKS scheme. I find the evaluation key for relinearization is defined like this: $evk =\left(-a_0 \cdot s+e_0+p \cdot s^2, a_0\right) \bmod p \cdot q$，where $p$ is a ...
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2 votes
0 answers
102 views
Is it possible to have a homomorphically encrypted Von Neumann machine?
Imagine Merlin delivers Arthur a blob of data representing a virtual machine state, encrypted via fully homomorphic encryption. This means that Arthur can compute arbitrary boolean circuits on this ...
- 229
1 vote
1 answer
114 views
Homomorphic encryption for computation of $bx+y\bmod p$
I'd want a public-key encryption scheme with plaintext space the integers modulo some public prime $p$, allowing the computation of a ciphertext that deciphers to $bx+y\bmod p$, given a public integer ...
- 151k
2 votes
2 answers
210 views
How to perform bitwise XOR by rational function modulo $2^n$?
Does there exist a rational function modulo $2^n$? This is a function of the form $$f(a,b)\pmod{2^n},$$ such that $$\forall\;a,b\in \{0,1,\ldots,2^n-1\},\quad a\oplus b=\frac{g(a,b)}{h(a,b)}\pmod{2^n},...
- 31
1 vote
2 answers
154 views
Is any FHE scheme faster than the trivial one?
There is an "trivial" FHE method where the client uses normal symmetric cryptography to encrypt, the server "performs the computation" by pretending the function to be performed to ...
- 402
2 votes
0 answers
47 views
Exploring Schemes for Additive Homomorphism and Nested Encryption
Is there an algorithm that satisfies both additive homomorphism and allows for double encryption? That is: $$m = Dec_{sk_2}(Dec_{sk_1}(Enc_{pk_2}(Enc_{pk_1}(m))))$$ $$Enc_{pk}(m_1) + Enc_{pk}(m_2) = ...
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