# Evaluate Sign From BGV to BinFHE

**URL:** <https://openfhe.discourse.group/t/evaluate-sign-from-bgv-to-binfhe/561>\
**Category:** Library Questions\
**Created:** [May 17, 2023, 10:06am UTC](https://openfhe.discourse.group/t/evaluate-sign-from-bgv-to-binfhe/561 "2023-05-17T10:06:13Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![miiip](https://avatars.discourse-cdn.com/v4/letter/m/a183cd/32.png) [@miiip](https://openfhe.discourse.group/u/miiip)\
**Post date:** [May 17, 2023, 10:06am UTC](https://openfhe.discourse.group/t/evaluate-sign-from-bgv-to-binfhe/561/1 "2023-05-17T10:06:13Z")

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Hi all!

I’m new to OpenFHE and I want to evaluate the sign of a BGV encrypted integer. I know that in [eval\_sign example](https://github.com/openfheorg/openfhe-development/blob/main/src/binfhe/examples/eval-sign.cpp) you mention:

> Instead, we assume that an LWE ciphertext with large ciphertext modulus is already provided (e.g., by extracting from a CKKS ciphertext).

My question is:  
How to instantiate the BinFHEContext context and how to pass the BGV ciphertext to EvalSign ?

Thank you!

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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:** [May 18, 2023, 10:16pm UTC](https://openfhe.discourse.group/t/evaluate-sign-from-bgv-to-binfhe/561/2 "2023-05-18T22:16:05Z")

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Hi @miiip If I understand your question correctly, you are asking a question about the scenario where you have a BGV ciphertext and you want to perform comparison using FHEW/TFHE, i.e., `EvalSign`, and then come back to BGV, correct? If yes, this requires scheme switching between BGV and FHEW/TFHE, which is not currently implemented in OpenFHE. We are currently adding scheme switching from CKKS ↔ FHEW/TFHE (it will be included in v1.1). The BGV scenario will be added in later versions.