# FHE Questions **URL:** https://openfhe.discourse.group/c/fhe-questions/18.md?page=2 [Latest](https://openfhe.discourse.group/latest.md) · [Categories](https://openfhe.discourse.group/categories.md) · [Tags](https://openfhe.discourse.group/tags.md) **Page:** 3 --- ## [Research on Homomorphic Pseudorandom Number Generation?](https://openfhe.discourse.group/t/research-on-homomorphic-pseudorandom-number-generation/1619)
**Author:** [@jkav77](https://openfhe.discourse.group/u/jkav77)\ **Replies:** 2\ **Last updated:** [October 6, 2024, 1:19am UTC](https://openfhe.discourse.group/t/research-on-homomorphic-pseudorandom-number-generation/1619 "2024-10-06T01:19:06Z")
Hello, I am wondering if anyone in the community here is aware of any research in homomorphically generating pseudorandom numbers given a provided random seed. I haven’t found anything but my searches are confounded by … --- ## [Transciphering with AES](https://openfhe.discourse.group/t/transciphering-with-aes/1607)
**Author:** [@sp18](https://openfhe.discourse.group/u/sp18)\ **Replies:** 3\ **Last updated:** [October 2, 2024, 2:17pm UTC](https://openfhe.discourse.group/t/transciphering-with-aes/1607 "2024-10-02T14:17:31Z")
This paper here specified that symmetric ciphers like AES is not a good choice for Hybrid Homomorphic Encryption due to large multiplicative depth. How is the multiplicative depth of AES computed here, is it while homomo… --- ## [Methods that surpass ALS in a privacy-preserving advertising system using FHE](https://openfhe.discourse.group/t/methods-that-surpass-als-in-a-privacy-preserving-advertising-system-using-fhe/1617)
**Author:** [@maskoff](https://openfhe.discourse.group/u/maskoff)\ **Replies:** 0\ **Last updated:** [October 2, 2024, 8:54am UTC](https://openfhe.discourse.group/t/methods-that-surpass-als-in-a-privacy-preserving-advertising-system-using-fhe/1617 "2024-10-02T08:54:07Z")
I’m doing a research on a privacy-preserving advertising system, especially searching for ALS alternatives that will be compatible with FHE. I discovered some of them, but not competent enough to choose the best one of t… --- ## [BGV Bootstrapping](https://openfhe.discourse.group/t/bgv-bootstrapping/1593)
**Author:** [@sp18](https://openfhe.discourse.group/u/sp18)\ **Replies:** 5\ **Last updated:** [September 26, 2024, 11:33pm UTC](https://openfhe.discourse.group/t/bgv-bootstrapping/1593 "2024-09-26T23:33:27Z")
Hi! Could anyone link to the bootstrap algorithm paper for BGV based FHE? --- ## [TFHE ciphertext](https://openfhe.discourse.group/t/tfhe-ciphertext/1598)
**Author:** [@sp18](https://openfhe.discourse.group/u/sp18)\ **Replies:** 2\ **Last updated:** [September 23, 2024, 9:23pm UTC](https://openfhe.discourse.group/t/tfhe-ciphertext/1598 "2024-09-23T21:23:06Z")
Any reason why p and q are powers of 2 and not primes in TFHE scheme? --- ## [Confusion with BGV](https://openfhe.discourse.group/t/confusion-with-bgv/1587)
**Author:** [@sp18](https://openfhe.discourse.group/u/sp18)\ **Replies:** 5\ **Last updated:** [September 20, 2024, 8:29pm UTC](https://openfhe.discourse.group/t/confusion-with-bgv/1587 "2024-09-20T20:29:33Z")
In the original BGV paper, the ciphertext contains just one component, whereas here in the library, the BGV implementation as well as in other libraries has 2 ciphertext components per ciphertext. Why is this difference?… --- ## [Source of noise and noise growth in RNS-CKKS](https://openfhe.discourse.group/t/source-of-noise-and-noise-growth-in-rns-ckks/1507)
**Author:** [@Alberto](https://openfhe.discourse.group/u/Alberto)\ **Replies:** 11\ **Last updated:** [September 19, 2024, 11:08am UTC](https://openfhe.discourse.group/t/source-of-noise-and-noise-growth-in-rns-ckks/1507 "2024-09-19T11:08:54Z")
Hello everyone, I am currently working with OpenFHE’s implementation of CKKS with bootstrapping. My use case involves running hundreds, if not thousands, of iterations and bootstrapping operations. As a result, I’m enco… --- ## [How to multiply between each elements of a encrypted vector to save memory? CKKS](https://openfhe.discourse.group/t/how-to-multiply-between-each-elements-of-a-encrypted-vector-to-save-memory-ckks/1577)
**Author:** [@Jason](https://openfhe.discourse.group/u/Jason)\ **Replies:** 1\ **Last updated:** [September 18, 2024, 12:15am UTC](https://openfhe.discourse.group/t/how-to-multiply-between-each-elements-of-a-encrypted-vector-to-save-memory-ckks/1577 "2024-09-18T00:15:20Z")
In CKKS scheme, I have a encrypted ciphertext of a vector. I need to multiply each elements of ciphertext. I can do by EvalMult, EvalRotate. But this way multiplicative depth will increase. It is resourcefully expensive.… --- ## [Slot-shuffling homomorphically](https://openfhe.discourse.group/t/slot-shuffling-homomorphically/170)
**Author:** [@radhika](https://openfhe.discourse.group/u/radhika)\ **Replies:** 7\ **Last updated:** [September 18, 2024, 12:00am UTC](https://openfhe.discourse.group/t/slot-shuffling-homomorphically/170 "2024-09-18T00:00:03Z")
Is there an example implementation of slot-shuffling homomorphically in the library? Or is it possible that there was a POC done for the same in threshold holomorphic encryption? I understand that it can be done using t… --- ## [Chebyshev vs Optimal Minimax Polynomial Approximation](https://openfhe.discourse.group/t/chebyshev-vs-optimal-minimax-polynomial-approximation/1578)
**Author:** [@seyda](https://openfhe.discourse.group/u/seyda)\ **Replies:** 2\ **Last updated:** [September 17, 2024, 3:04pm UTC](https://openfhe.discourse.group/t/chebyshev-vs-optimal-minimax-polynomial-approximation/1578 "2024-09-17T15:04:49Z")
Hello everyone, as far as I know, the CKKS bootstrapping in the literature diverges around 2021 between two methods: Bossuat et al. implements bootstrapping with depth-optimal Chebyshev interpolant evaluation via BSGS … --- ## [Convolutional Layer with FHE](https://openfhe.discourse.group/t/convolutional-layer-with-fhe/1564)
**Author:** [@seyda](https://openfhe.discourse.group/u/seyda)\ **Replies:** 8\ **Last updated:** [September 12, 2024, 1:36pm UTC](https://openfhe.discourse.group/t/convolutional-layer-with-fhe/1564 "2024-09-12T13:36:59Z")
Hello everyone, I have some questions on doing the convolution operation on encrypted data: Suppose we have a ciphertext encrypting a (32x32) image with ring dimension N = 4096 and a convolutional filter with size (3x3)… --- ## [Some questions about GPU acceletarion](https://openfhe.discourse.group/t/some-questions-about-gpu-acceletarion/1565)
**Author:** [@xiaruo](https://openfhe.discourse.group/u/xiaruo)\ **Replies:** 1\ **Last updated:** [September 12, 2024, 2:53am UTC](https://openfhe.discourse.group/t/some-questions-about-gpu-acceletarion/1565 "2024-09-12T02:53:49Z")
Hello, I am very curious about GPU acceletarion. I have noticed that GPU acceleration has not yet been implemented in many mainstream fully homomorphic encryption libraries. Now, I have the following questions: Why can… --- ## [There are upper bounds (Big O notation) for size or execution speed of RLWE](https://openfhe.discourse.group/t/there-are-upper-bounds-big-o-notation-for-size-or-execution-speed-of-rlwe/1552)
**Author:** [@JuriusStep](https://openfhe.discourse.group/u/JuriusStep)\ **Replies:** 1\ **Last updated:** [September 11, 2024, 1:24pm UTC](https://openfhe.discourse.group/t/there-are-upper-bounds-big-o-notation-for-size-or-execution-speed-of-rlwe/1552 "2024-09-11T13:24:26Z")
s in the LWE-based cryptosystem there some upper bound, like Private key size: nllog q Public key size: m(n + L) log q Message size: l log t Ciphertext size: (n + \`) log q Link:https://cims.nyu.edu/~regev/papers/pqc… --- ## [Comparison of CKKS scheme between OpenFHE and TenSeal](https://openfhe.discourse.group/t/comparison-of-ckks-scheme-between-openfhe-and-tenseal/1466)
**Author:** [@shibaInu](https://openfhe.discourse.group/u/shibaInu)\ **Replies:** 11\ **Last updated:** [September 10, 2024, 9:12pm UTC](https://openfhe.discourse.group/t/comparison-of-ckks-scheme-between-openfhe-and-tenseal/1466 "2024-09-10T21:12:43Z")
Hi, I’m trying to compare CKKS scheme between OpenFHE and TenSeal in Python. The experiment settings are: 128 security level Polynomial degree (N) = 8192 First Mod Size (Q0) = 60 Scaling Mod Size = 49 Multiplicative … --- ## [Mod switch on fresh ciphertext](https://openfhe.discourse.group/t/mod-switch-on-fresh-ciphertext/1544)
**Author:** [@narger](https://openfhe.discourse.group/u/narger)\ **Replies:** 1\ **Last updated:** [September 8, 2024, 10:18pm UTC](https://openfhe.discourse.group/t/mod-switch-on-fresh-ciphertext/1544 "2024-09-08T22:18:18Z")
Hello there, I am trying to study the BGV scheme as described in your implementation, in particular I tried to implement a toy modulus switching. Given a ciphertext with an error bound B^2, the idea is to scale it down … --- ## [Avoiding the Adjust Operation in CKKS](https://openfhe.discourse.group/t/avoiding-the-adjust-operation-in-ckks/1534)
**Author:** [@seyda](https://openfhe.discourse.group/u/seyda)\ **Replies:** 3\ **Last updated:** [September 4, 2024, 5:26pm UTC](https://openfhe.discourse.group/t/avoiding-the-adjust-operation-in-ckks/1534 "2024-09-04T17:26:03Z")
Hello everyone, I have a question on the Adjust operation before the cross-level addition or multiplication operations in CKKS. As It incurs several rescale operations (on the ciphertext with the higher #limbs), I am thi… --- ## [How to find Hamming weight](https://openfhe.discourse.group/t/how-to-find-hamming-weight/1523)
**Author:** [@JuriusStep](https://openfhe.discourse.group/u/JuriusStep)\ **Replies:** 1\ **Last updated:** [August 31, 2024, 12:35am UTC](https://openfhe.discourse.group/t/how-to-find-hamming-weight/1523 "2024-08-31T00:35:30Z")
For KeyGen is used Hamming weight is exactly h. I do not understand how to define h --- ## [Can not change Security Level by changing Ring Dimension and logQ](https://openfhe.discourse.group/t/can-not-change-security-level-by-changing-ring-dimension-and-logq/1520)
**Author:** [@JuriusStep](https://openfhe.discourse.group/u/JuriusStep)\ **Replies:** 1\ **Last updated:** [August 30, 2024, 7:55pm UTC](https://openfhe.discourse.group/t/can-not-change-security-level-by-changing-ring-dimension-and-logq/1520 "2024-08-30T19:55:18Z")
In my Application i changed N from 15 to 17 and loqQ from 230 to 580 By using “parameters.GetSecurityLevel())” i get always HEStd\_128\_classic Because of Standart Security Level of ist not the same Security Level of --- ## [Current community security standard](https://openfhe.discourse.group/t/current-community-security-standard/1494)
**Author:** [@JuriusStep](https://openfhe.discourse.group/u/JuriusStep)\ **Replies:** 4\ **Last updated:** [August 19, 2024, 4:03pm UTC](https://openfhe.discourse.group/t/current-community-security-standard/1494 "2024-08-19T16:03:31Z")
Are there any reasons why the last community standard is from November 2018 (Standard – Homomorphic Encryption Standardization)? --- ## [\[CKKS\] Relations between bootstrapping, noise and precision](https://openfhe.discourse.group/t/ckks-relations-between-bootstrapping-noise-and-precision/1493)
**Author:** [@Alberto](https://openfhe.discourse.group/u/Alberto)\ **Replies:** 5\ **Last updated:** [August 15, 2024, 4:02pm UTC](https://openfhe.discourse.group/t/ckks-relations-between-bootstrapping-noise-and-precision/1493 "2024-08-15T16:02:33Z")
Hi there, I have a few questions regarding the bootstrapping process in the CKKS scheme. From my understanding of the bootstrapping operation in schemes such as TFHE, its goal is to refresh the ciphertext by homomorphica… --- ## [How choose security level](https://openfhe.discourse.group/t/how-choose-security-level/1485)
**Author:** [@JuriusStep](https://openfhe.discourse.group/u/JuriusStep)\ **Replies:** 1\ **Last updated:** [August 12, 2024, 3:25pm UTC](https://openfhe.discourse.group/t/how-choose-security-level/1485 "2024-08-12T15:25:05Z")
I read https://homomorphicencryption.org/wp-content/uploads/2018/11/HomomorphicEncryptionStandardv1.1.pdf with tables of parameters. i am confused, for example im table i can chosse sl-256 with n=1024, but im my appli… --- ## [RLWE x RGSW algorithm questions for BinFHE example](https://openfhe.discourse.group/t/rlwe-x-rgsw-algorithm-questions-for-binfhe-example/1428)
**Author:** [@Yunhao](https://openfhe.discourse.group/u/Yunhao)\ **Replies:** 4\ **Last updated:** [August 5, 2024, 5:54pm UTC](https://openfhe.discourse.group/t/rlwe-x-rgsw-algorithm-questions-for-binfhe-example/1428 "2024-08-05T17:54:55Z")
Hi there, I am trying to understand the code of RLWE x RGSW inside this file: openfhe-development/src/binfhe/lib/rgsw-acc-dm.cpp at main · openfheorg/openfhe-development · GitHub with respect to your paper: https://epri… --- ## [Question on gadgets sampling](https://openfhe.discourse.group/t/question-on-gadgets-sampling/1464)
**Author:** [@narger](https://openfhe.discourse.group/u/narger)\ **Replies:** 4\ **Last updated:** [August 2, 2024, 12:31pm UTC](https://openfhe.discourse.group/t/question-on-gadgets-sampling/1464 "2024-08-02T12:31:11Z")
Hello everyone, I am studying the implementation of FHEW-style cryptosystems (BinFHE), and I have a question about gadgets. I know that they are matrices that define very simple lattices in which discrete (sub)gaussian … --- ## [TFHE multiplication](https://openfhe.discourse.group/t/tfhe-multiplication/1465)
**Author:** [@sp18](https://openfhe.discourse.group/u/sp18)\ **Replies:** 3\ **Last updated:** [August 1, 2024, 2:27pm UTC](https://openfhe.discourse.group/t/tfhe-multiplication/1465 "2024-08-01T14:27:02Z")
Does TFHE support only homomorphic addition for two LWE/RLWE ciphertexts and multiplication with constants (polynomials in RLWE)? AFAIK, it supports homomorphic multiplication of only two RGSW ciphertexts, or external pr… --- ## [Calculating max size of q](https://openfhe.discourse.group/t/calculating-max-size-of-q/1463)
**Author:** [@JuriusStep](https://openfhe.discourse.group/u/JuriusStep)\ **Replies:** 3\ **Last updated:** [July 31, 2024, 6:25pm UTC](https://openfhe.discourse.group/t/calculating-max-size-of-q/1463 "2024-07-31T18:25:11Z")
In paper (https://arxiv.org/pdf/2202.07994) there is table with max size of q for differens security level and ring dimesion. How do they calculate such coeff modulus --- ## [How does CKKS Sparse Encoding work exactly?](https://openfhe.discourse.group/t/how-does-ckks-sparse-encoding-work-exactly/1450)
**Author:** [@ephemer4l](https://openfhe.discourse.group/u/ephemer4l)\ **Replies:** 8\ **Last updated:** [July 26, 2024, 6:15pm UTC](https://openfhe.discourse.group/t/how-does-ckks-sparse-encoding-work-exactly/1450 "2024-07-26T18:15:30Z")
I’ve been going through the bootstrapping paper and I just can’t seem to understand how they are doing the embedding in part 4.4. Does anyone have insight into what exact function they use to do this? The decoding part i… --- ## [OpenFHE Server Usage](https://openfhe.discourse.group/t/openfhe-server-usage/1410)
**Author:** [@KitchM](https://openfhe.discourse.group/u/KitchM)\ **Replies:** 7\ **Last updated:** [July 26, 2024, 1:20pm UTC](https://openfhe.discourse.group/t/openfhe-server-usage/1410 "2024-07-26T13:20:13Z")
Is OpenFHE something that can be used on a web server to guarantee anonymity on use and processing? Thanks. --- ## [Exp(x) is CKKS without ChebyshevFunction](https://openfhe.discourse.group/t/exp-x-is-ckks-without-chebyshevfunction/1437)
**Author:** [@sumw](https://openfhe.discourse.group/u/sumw)\ **Replies:** 2\ **Last updated:** [July 22, 2024, 2:39pm UTC](https://openfhe.discourse.group/t/exp-x-is-ckks-without-chebyshevfunction/1437 "2024-07-22T14:39:53Z")
Since ChebyshevFunction requires relatively large parameters, is there a way in CKKS to evaluate exp(x) without using ChebyshevFunction? --- ## [How can I simulate the logarithmic function on BinFHE through LUT?](https://openfhe.discourse.group/t/how-can-i-simulate-the-logarithmic-function-on-binfhe-through-lut/1426)
**Author:** [@zgl404](https://openfhe.discourse.group/u/zgl404)\ **Replies:** 3\ **Last updated:** [July 16, 2024, 8:56pm UTC](https://openfhe.discourse.group/t/how-can-i-simulate-the-logarithmic-function-on-binfhe-through-lut/1426 "2024-07-16T20:56:26Z")
I am interested in utilizing the logarithmic function within the BinFHE framework. However, I am not well-versed with the process. Could you guide me on how to achieve a logarithmic function simulation that is both swift… --- ## [GPU based Matrix Multiplication for TFHE and CKKS?](https://openfhe.discourse.group/t/gpu-based-matrix-multiplication-for-tfhe-and-ckks/1419)
**Author:** [@prikmm](https://openfhe.discourse.group/u/prikmm)\ **Replies:** 2\ **Last updated:** [July 13, 2024, 6:28pm UTC](https://openfhe.discourse.group/t/gpu-based-matrix-multiplication-for-tfhe-and-ckks/1419 "2024-07-13T18:28:03Z")
Hey folks, I am new to FHE and want to use it for my deep learning project. I have just started understanding TFHE and CKKS and I have a question. How to do matrix multiplication in both on GPU? After exploring CKKS si… [Previous page](https://openfhe.discourse.group/c/fhe-questions/18.md?page=1) [Next page](https://openfhe.discourse.group/c/fhe-questions/18.md?page=3)