# Threshold CKKS for ciphertext plaintext multiplication

**URL:** <https://openfhe.discourse.group/t/threshold-ckks-for-ciphertext-plaintext-multiplication/331>\
**Category:** Library Questions\
**Created:** [February 3, 2023, 6:10am UTC](https://openfhe.discourse.group/t/threshold-ckks-for-ciphertext-plaintext-multiplication/331 "2023-02-03T06:10:29Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Cyptic6796](https://avatars.discourse-cdn.com/v4/letter/c/a6a055/32.png) [@Cyptic6796](https://openfhe.discourse.group/u/Cyptic6796)\
**Post date:** [February 3, 2023, 6:10am UTC](https://openfhe.discourse.group/t/threshold-ckks-for-ciphertext-plaintext-multiplication/331/1 "2023-02-03T06:10:29Z")

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Hello,  
I am working on a project that hopes to use ciphertext plaintext multiplication, I check the example file and the [unit test file](https://github.com/openfheorg/openfhe-development/blob/main/src/pke/unittest/UnitTestMultiparty.cpp#L341) but couldn’t find an example. If it is implemented(I guess so), could you kindly provide a usage case? Otherwise, will it be released in a future version or I need to implement it if I hope to use it in my project.  
Thanks so much!

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**Author:** ![Cyptic6796](https://avatars.discourse-cdn.com/v4/letter/c/a6a055/32.png) [@Cyptic6796](https://openfhe.discourse.group/u/Cyptic6796)\
**Post date:** [February 3, 2023, 6:05pm UTC](https://openfhe.discourse.group/t/threshold-ckks-for-ciphertext-plaintext-multiplication/331/3 "2023-02-03T18:05:02Z")

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Hi iquah,  
Thanks so much for your help!  
But I actually wonder if the plaintext ciphertext **multiplication** is available in the **threshold CKKS setting.** More specifically, I want to do x1 = {0.25, 0.5, 0.75, 1.0, 2.0, 3.0, 4.0, 5.0};  
x2 = {0,1,0,1,0,1,0,1}  
denote by c1 the ciphertext of x1 and p2 the plaintext of x2.

if it is possible to do evalmult(c1,p2).  
Thanks again for your help!

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**Author:** ![ypolyakov](https://yyz1.discourse-cdn.com/flex031/user_avatar/openfhe.discourse.group/ypolyakov/32/47_2.png) [@ypolyakov](https://openfhe.discourse.group/u/ypolyakov)\
**Post date:** [February 6, 2023, 5:19pm UTC](https://openfhe.discourse.group/t/threshold-ckks-for-ciphertext-plaintext-multiplication/331/4 "2023-02-06T17:19:08Z")

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Hi @Cyptic6796,

Yes, evalmult(c1,p2) is supported in OpenFHE (it is supported for both single-key and threshold FHE setting). Here is an example in unit tests: [openfhe-development/UnitTestCKKSrns.cpp at main · openfheorg/openfhe-development · GitHub](https://github.com/openfheorg/openfhe-development/blob/main/src/pke/unittest/utckksrns/UnitTestCKKSrns.cpp#L847)

The full API for `CryptoContext` is available at [Template Class CryptoContextImpl — OpenFHE documentation](https://openfhe-development.readthedocs.io/en/latest/api/classlbcrypto_1_1CryptoContextImpl.html#_CPPv4NK8lbcrypto17CryptoContextImpl8EvalMultE15ConstCiphertextI7ElementE14ConstPlaintext)