# \#questions **URL:** https://openfhe.discourse.group/tag/questions/10.md [Latest](https://openfhe.discourse.group/latest.md) · [Categories](https://openfhe.discourse.group/categories.md) · [Tags](https://openfhe.discourse.group/tags.md) --- ## [What is the purpose of Block classes?](https://openfhe.discourse.group/t/what-is-the-purpose-of-block-classes/2330)
**Author:** [@nbui](https://openfhe.discourse.group/u/nbui)\ **Replies:** 2\ **Last updated:** [June 25, 2026, 10:18pm UTC](https://openfhe.discourse.group/t/what-is-the-purpose-of-block-classes/2330 "2026-06-25T22:18:46Z")
I see that there are BlockCTArray, BlockPTArray, BlockFHETensor classes in the Git repo. The classes don’t seem to have an implementation. I was wondering if what the purpose of these classes will be? I’m working on a p… --- ## [Understanding CKKS precision limits for large magnitude values](https://openfhe.discourse.group/t/understanding-ckks-precision-limits-for-large-magnitude-values/2313)
**Author:** [@Claire](https://openfhe.discourse.group/u/Claire)\ **Replies:** 1\ **Last updated:** [April 22, 2026, 3:41pm UTC](https://openfhe.discourse.group/t/understanding-ckks-precision-limits-for-large-magnitude-values/2313 "2026-04-22T15:41:59Z")
Hello, I am trying to understand the practical limitations on double-precision values when using CKKS. In standard 64-bit floating-point arithmetic, we have a 52-bit mantissa. However, in CKKS, due to ciphertext repres… --- ## [Polynomial representation of ciphertext from MakeCoefPackedPlaintext](https://openfhe.discourse.group/t/polynomial-representation-of-ciphertext-from-makecoefpackedplaintext/2303)
**Author:** [@krist](https://openfhe.discourse.group/u/krist)\ **Replies:** 2\ **Last updated:** [March 21, 2026, 8:24am UTC](https://openfhe.discourse.group/t/polynomial-representation-of-ciphertext-from-makecoefpackedplaintext/2303 "2026-03-21T08:24:34Z")
When encrypting a plaintext from MakeCoefPackedPlaintext does the resulting ciphertext use Poly, NativePoly or DCRTPoly to represent it? Or something else entirely? If it makes a difference I am using the Python version … --- ## [Impact of ScalingModSize and/or FirstModSIze choices](https://openfhe.discourse.group/t/impact-of-scalingmodsize-and-or-firstmodsize-choices/2302)
**Author:** [@krist](https://openfhe.discourse.group/u/krist)\ **Replies:** 2\ **Last updated:** [March 21, 2026, 8:23am UTC](https://openfhe.discourse.group/t/impact-of-scalingmodsize-and-or-firstmodsize-choices/2302 "2026-03-21T08:23:35Z")
Are computations for faster for lower values ScalingModSize and/or FirstModeSize? Or is it generally better to use the highest values allowed for a particular ring dimension? Also, does the values of ScalingModSize and/… --- ## [Using NOISE\_FLOODING\_DECRYPT for CKKS in a multiparty setting](https://openfhe.discourse.group/t/using-noise-flooding-decrypt-for-ckks-in-a-multiparty-setting/2297)
**Author:** [@krist](https://openfhe.discourse.group/u/krist)\ **Replies:** 5\ **Last updated:** [March 13, 2026, 9:06am UTC](https://openfhe.discourse.group/t/using-noise-flooding-decrypt-for-ckks-in-a-multiparty-setting/2297 "2026-03-13T09:06:45Z")
Hello. I am trying to use the NOISE\_FLOODING\_DECRYPT mode for CKKS in a multiparty setting in the Python version of OpenFHE. This post Support for NOISE\_FLOODING\_MULTIPARTY in threshold CKKS? - Library Questions - Open… --- ## [Coef encoding vs CRT encoding](https://openfhe.discourse.group/t/coef-encoding-vs-crt-encoding/2300)
**Author:** [@krist](https://openfhe.discourse.group/u/krist)\ **Replies:** 2\ **Last updated:** [March 12, 2026, 6:51pm UTC](https://openfhe.discourse.group/t/coef-encoding-vs-crt-encoding/2300 "2026-03-12T18:51:53Z")
Hello. I have been watching webinars Homomorphic Encryption for OpenFHE Users – OpenFHE.org and reading forum posts such as Ressources for Batching, but I am wondering if my understanding is correct. For coef encoding,… --- ## [Possible values for ScalingModSize in BFV](https://openfhe.discourse.group/t/possible-values-for-scalingmodsize-in-bfv/2294)
**Author:** [@krist](https://openfhe.discourse.group/u/krist)\ **Replies:** 2\ **Last updated:** [March 10, 2026, 10:48am UTC](https://openfhe.discourse.group/t/possible-values-for-scalingmodsize-in-bfv/2294 "2026-03-10T10:48:20Z")
Hello. I am trying to use BFV for encrypting vectors which can contain values \\{-1, 0, 1\\}. The use case is for multiparty with 3 Clients. The Version being used in the Python wrapper. I have been experimenting with di… --- ## [OpenFHE v1.4.2+ with HEXL: supported branch/tag?](https://openfhe.discourse.group/t/openfhe-v1-4-2-with-hexl-supported-branch-tag/2288)
**Author:** [@Gabba](https://openfhe.discourse.group/u/Gabba)\ **Replies:** 1\ **Last updated:** [March 2, 2026, 7:03pm UTC](https://openfhe.discourse.group/t/openfhe-v1-4-2-with-hexl-supported-branch-tag/2288 "2026-03-02T19:03:59Z")
Hi all, I’m benchmarking CKKS workloads on an AVX-512 capable AWS Intel Xeon (Ice Lake). I’d like to use OpenFHE v1.4.2 (stable) or newer (e.g., v1.5.0 dev). However, the official openfhe-hexl README states it “can be … --- ## [Question on Two Implementation of Composite Rescaling](https://openfhe.discourse.group/t/question-on-two-implementation-of-composite-rescaling/2269)
**Author:** [@JianmingTong](https://openfhe.discourse.group/u/JianmingTong)\ **Replies:** 3\ **Last updated:** [January 28, 2026, 5:01pm UTC](https://openfhe.discourse.group/t/question-on-two-implementation-of-composite-rescaling/2269 "2026-01-28T17:01:14Z")
Hi! I found the current composite rescaling is implemented by iteratively dropping the last moduli until the number of dropped moduli hit the level (i.e. the composite degree), as detailed in this link: Would there be … --- ## [Hierarchical parallel with OpenFHE using OpenMP](https://openfhe.discourse.group/t/hierarchical-parallel-with-openfhe-using-openmp/2259)
**Author:** [@cappuccino](https://openfhe.discourse.group/u/cappuccino)\ **Replies:** 2\ **Last updated:** [January 22, 2026, 3:33pm UTC](https://openfhe.discourse.group/t/hierarchical-parallel-with-openfhe-using-openmp/2259 "2026-01-22T15:33:51Z")
Hi I’m researching parallel processing using CKKS, and it seems the OpenFHE library internally implements parallel processing using OpenMP. I’d like to perform hierarchical parallel processing using the code below. Is … --- ## [Eval Key Management Concurrent Requests](https://openfhe.discourse.group/t/eval-key-management-concurrent-requests/2224)
**Author:** [@srovira](https://openfhe.discourse.group/u/srovira)\ **Replies:** 3\ **Last updated:** [December 20, 2025, 12:02am UTC](https://openfhe.discourse.group/t/eval-key-management-concurrent-requests/2224 "2025-12-20T00:02:42Z")
Hello, I’m trying to understand better how eval keys should be managed in OpenFHE. Assume that we have the following scenario. We run a typical client-server application, where the client sends eval keys, the server do… --- ## [Evaluating BinGate on LWECiphertext after CKKS to FHEW scheme switching](https://openfhe.discourse.group/t/evaluating-bingate-on-lweciphertext-after-ckks-to-fhew-scheme-switching/2229)
**Author:** [@Omar](https://openfhe.discourse.group/u/Omar)\ **Replies:** 4\ **Last updated:** [December 12, 2025, 4:29pm UTC](https://openfhe.discourse.group/t/evaluating-bingate-on-lweciphertext-after-ckks-to-fhew-scheme-switching/2229 "2025-12-12T16:29:04Z")
Hello, I’m trying to convert two CKKS ciphertexts into their encrypted bits (FHEW ciphertexts) using scheme switching. Extracting the bits from the converted CKKS ciphertext is working fine. But, when I perform the XOR … --- ## [How to set Q value](https://openfhe.discourse.group/t/how-to-set-q-value/2231)
**Author:** [@cappuccino](https://openfhe.discourse.group/u/cappuccino)\ **Replies:** 6\ **Last updated:** [December 11, 2025, 4:06pm UTC](https://openfhe.discourse.group/t/how-to-set-q-value/2231 "2025-12-11T16:06:19Z")
Hello developers! I have a question about mod Q in CKKS. I understand that the OpenFHE specifications determine a certain mod Q value when N is set. And to set a large mod Q, I can use the parameters.SetNumLargeDigits… --- ## [Replicate inner product result to each element of the result](https://openfhe.discourse.group/t/replicate-inner-product-result-to-each-element-of-the-result/2233)
**Author:** [@DarkFrak74](https://openfhe.discourse.group/u/DarkFrak74)\ **Replies:** 2\ **Last updated:** [December 11, 2025, 10:13am UTC](https://openfhe.discourse.group/t/replicate-inner-product-result-to-each-element-of-the-result/2233 "2025-12-11T10:13:22Z")
Hi, I’m trying to perform an inner product and then apply a Chebyshev function approximation to the result. However, for the final result of my operation (as the last operation will be an element-wise multiplication), I … --- ## [Mod reduction error](https://openfhe.discourse.group/t/mod-reduction-error/2225)
**Author:** [@cappuccino](https://openfhe.discourse.group/u/cappuccino)\ **Replies:** 6\ **Last updated:** [December 5, 2025, 7:49am UTC](https://openfhe.discourse.group/t/mod-reduction-error/2225 "2025-12-05T07:49:48Z")
Hello, fellow developers. I’m using CKKS with ML, and I have a question about mod reduction. I’m using the ModReduce function to speed things up, but I encountered an error when using this function. Below is a simplif… --- ## ["The decryption failed because the approximation error is too high. Check the parameters" with bootstrapping](https://openfhe.discourse.group/t/the-decryption-failed-because-the-approximation-error-is-too-high-check-the-parameters-with-bootstrapping/2206)
**Author:** [@cappuccino](https://openfhe.discourse.group/u/cappuccino)\ **Replies:** 2\ **Last updated:** [November 7, 2025, 8:04am UTC](https://openfhe.discourse.group/t/the-decryption-failed-because-the-approximation-error-is-too-high-check-the-parameters-with-bootstrapping/2206 "2025-11-07T08:04:22Z")
I’m using the CKKS cipher and encountered the following error: The decryption failed because the approximation error is too high. Check the parameters. I checked out Error “The decryption failed because the approximati… --- ## [About precision, scale value and basic operation of boot strapping](https://openfhe.discourse.group/t/about-precision-scale-value-and-basic-operation-of-boot-strapping/2204)
**Author:** [@cappuccino](https://openfhe.discourse.group/u/cappuccino)\ **Replies:** 3\ **Last updated:** [November 6, 2025, 5:03pm UTC](https://openfhe.discourse.group/t/about-precision-scale-value-and-basic-operation-of-boot-strapping/2204 "2025-11-06T17:03:26Z")
While using bootstrap with the following program, three questions came to mind. Isn’t the accuracy of the bootstrapped ciphertext low? I can observe a 50-bit → 10-bit error. The scale value of the bootstrapped ciph… --- ## [Can I use arbitrarily large ciphertext moduli (q\_i) in BGV/BFV?](https://openfhe.discourse.group/t/can-i-use-arbitrarily-large-ciphertext-moduli-q-i-in-bgv-bfv/2203)
**Author:** [@oksuman](https://openfhe.discourse.group/u/oksuman)\ **Replies:** 3\ **Last updated:** [November 6, 2025, 5:42am UTC](https://openfhe.discourse.group/t/can-i-use-arbitrarily-large-ciphertext-moduli-q-i-in-bgv-bfv/2203 "2025-11-06T05:42:46Z")
Hello, I’m wondering whether it is possible to use arbitrarily large ciphertext moduli (q\_i) in the BGV or BFV schemes. In particular, I would like to set a large first modulus (q\_0), up to about 800 bits. However, I f… --- ## [About bootstrapping parameters](https://openfhe.discourse.group/t/about-bootstrapping-parameters/2202)
**Author:** [@cappuccino](https://openfhe.discourse.group/u/cappuccino)\ **Replies:** 2\ **Last updated:** [October 31, 2025, 8:07pm UTC](https://openfhe.discourse.group/t/about-bootstrapping-parameters/2202 "2025-10-31T20:07:41Z")
Hello everyone I’m working on bootstrapping on CKKS. I have three questions: How does levelBudget work? What are the advantages of having a large levelBudget and a small levelBudget? As above, what is bsgsDim? Wh… --- ## [How to support 55 (q\_0) + 40 (q\_i), i\>0 in OpenFHE](https://openfhe.discourse.group/t/how-to-support-55-q-0-40-q-i-i-0-in-openfhe/2195)
**Author:** [@JianmingTong](https://openfhe.discourse.group/u/JianmingTong)\ **Replies:** 1\ **Last updated:** [October 20, 2025, 4:39pm UTC](https://openfhe.discourse.group/t/how-to-support-55-q-0-40-q-i-i-0-in-openfhe/2195 "2025-10-20T16:39:57Z")
Dear developers Might I seek guidance on how to implement the following security parameters inside OpenFHE and make it able to pass the 128-bit security checking? I’m using this example to test the bootstrapping open… --- ## [Cannot using HEStd\_128\_classic crashes my terminal](https://openfhe.discourse.group/t/cannot-using-hestd-128-classic-crashes-my-terminal/2187)
**Author:** [@Omar](https://openfhe.discourse.group/u/Omar)\ **Replies:** 1\ **Last updated:** [October 3, 2025, 6:59am UTC](https://openfhe.discourse.group/t/cannot-using-hestd-128-classic-crashes-my-terminal/2187 "2025-10-03T06:59:40Z")
Hello, I’m trying to run the following simple program in CKKS, it’s similar to the code in advanced-ckks-bootstrapping.cpp. I’m using WSL on Windows and the program compiles. But when I run it, it prints “CKKS scheme is… --- ## [Questions about MultiPrecision FBT](https://openfhe.discourse.group/t/questions-about-multiprecision-fbt/2177)
**Author:** [@Haow\_P](https://openfhe.discourse.group/u/Haow_P)\ **Replies:** 4\ **Last updated:** [September 25, 2025, 1:58pm UTC](https://openfhe.discourse.group/t/questions-about-multiprecision-fbt/2177 "2025-09-25T13:58:59Z")
Hi, I am currently working with the latest version of OpenFHE and trying to understand the Functional Bootstrapping (FBT) procedure. In the MultiPrecisionSign example in functional-bootstrapping-ckks.cpp, I have the fol… --- ## [Implementation of LeveledSHECKKSRNS::AdjustLevelsAndDepthInPlace](https://openfhe.discourse.group/t/implementation-of-leveledsheckksrns-adjustlevelsanddepthinplace/2168)
**Author:** [@srovira](https://openfhe.discourse.group/u/srovira)\ **Replies:** 1\ **Last updated:** [September 15, 2025, 5:52pm UTC](https://openfhe.discourse.group/t/implementation-of-leveledsheckksrns-adjustlevelsanddepthinplace/2168 "2025-09-15T17:52:26Z")
Hello, There are a few things I don’t understand in the implementation of the function LeveledSHECKKSRNS::AdjustLevelsAndDepthInPlace. For example, if c1lvl \< c2lvl and c1depth = c2depth = 2, the code first computes Ev… --- ## [How to compute the decryption error probability in CKKS (Generalized CKKS bootstrapping parameter setting)](https://openfhe.discourse.group/t/how-to-compute-the-decryption-error-probability-in-ckks-generalized-ckks-bootstrapping-parameter-setting/2171)
**Author:** [@srovira](https://openfhe.discourse.group/u/srovira)\ **Replies:** 1\ **Last updated:** [September 15, 2025, 5:31pm UTC](https://openfhe.discourse.group/t/how-to-compute-the-decryption-error-probability-in-ckks-generalized-ckks-bootstrapping-parameter-setting/2171 "2025-09-15T17:31:42Z")
Hello, In section 4.1 of the paper about generalized bootstrapping for CKKS, the following is mentioned: In scenarios where the IND-CPAD security model needs to be satisfied, the decryption failure probability must be… --- ## [Print Noise in OpenFHE](https://openfhe.discourse.group/t/print-noise-in-openfhe/2155)
**Author:** [@pikaqiu](https://openfhe.discourse.group/u/pikaqiu)\ **Replies:** 1\ **Last updated:** [September 5, 2025, 12:44am UTC](https://openfhe.discourse.group/t/print-noise-in-openfhe/2155 "2025-09-05T00:44:25Z")
How can I print noise with secretKey for bgvrns/bfvrns in openfhe-v1.4.0? Thank you very much for your help! --- ## [Calculating Security Level and logq in OpenFHE](https://openfhe.discourse.group/t/calculating-security-level-and-logq-in-openfhe/2149)
**Author:** [@seanmoris](https://openfhe.discourse.group/u/seanmoris)\ **Replies:** 3\ **Last updated:** [August 25, 2025, 9:32am UTC](https://openfhe.discourse.group/t/calculating-security-level-and-logq-in-openfhe/2149 "2025-08-25T09:32:27Z")
Hi all, I’m working on a CKKS application in OpenFHE and trying to determine the appropriate security level, but I’m a bit unsure about how to calculate it properly. I’ve been referring to the Homomorphic Encryption Sta… --- ## [Deserializing Ciphertexts is slow](https://openfhe.discourse.group/t/deserializing-ciphertexts-is-slow/2103)
**Author:** [@g\_tasop](https://openfhe.discourse.group/u/g_tasop)\ **Replies:** 6\ **Last updated:** [July 31, 2025, 4:54pm UTC](https://openfhe.discourse.group/t/deserializing-ciphertexts-is-slow/2103 "2025-07-31T16:54:00Z")
Hello, I am working on an application in a client-server setup where the two parties need to exchange a large number of Ciphertexts. Before sending them over the network the client needs to perform these operations for e… --- ## [How to create a Plaintext from a raw DCRTPoly for decoding?](https://openfhe.discourse.group/t/how-to-create-a-plaintext-from-a-raw-dcrtpoly-for-decoding/2113)
**Author:** [@Emmaka](https://openfhe.discourse.group/u/Emmaka)\ **Replies:** 2\ **Last updated:** [July 25, 2025, 9:06pm UTC](https://openfhe.discourse.group/t/how-to-create-a-plaintext-from-a-raw-dcrtpoly-for-decoding/2113 "2025-07-25T21:06:10Z")
I am implementing a custom multi-key CKKS protocol using OpenFHE’s low-level components (like DCRTPoly and the ring operators). My custom aggregation function successfully produces a final DCRTPoly which represents the … --- ## [How to transform a ciphertext from one slot count to another without decryption](https://openfhe.discourse.group/t/how-to-transform-a-ciphertext-from-one-slot-count-to-another-without-decryption/2097)
**Author:** [@haohaohao](https://openfhe.discourse.group/u/haohaohao)\ **Replies:** 1\ **Last updated:** [July 19, 2025, 5:37pm UTC](https://openfhe.discourse.group/t/how-to-transform-a-ciphertext-from-one-slot-count-to-another-without-decryption/2097 "2025-07-19T17:37:14Z")
Hello everyone! I’m working on a problem where I need to transform a ciphertext’s effective slot count without decrypting and re-encrypting. Context: I have a ciphertext with numSlots = 8 containing the plaintext: \[0.… --- ## [Total number of multiplications](https://openfhe.discourse.group/t/total-number-of-multiplications/2093)
**Author:** [@Atwo](https://openfhe.discourse.group/u/Atwo)\ **Replies:** 3\ **Last updated:** [July 12, 2025, 4:38pm UTC](https://openfhe.discourse.group/t/total-number-of-multiplications/2093 "2025-07-12T16:38:48Z")
Hello Everyone, The below is the default OpenFHE BFV code (https://github.com/openfheorg/openfhe-development/blob/main/src/pke/examples/simple-integers.cpp) with multiplicative depth 4. After 15 multiplications I am unb… [Next page](https://openfhe.discourse.group/tag/questions/10.md?match_all_tags=true&page=1&tags%5B%5D=questions)