# CKKS Bootstrapping gives incorrect results on scale != 60?

**URL:** <https://openfhe.discourse.group/t/ckks-bootstrapping-gives-incorrect-results-on-scale-60/844>\
**Category:** Library Questions\
**Created:** [October 13, 2023, 8:54am UTC](https://openfhe.discourse.group/t/ckks-bootstrapping-gives-incorrect-results-on-scale-60/844 "2023-10-13T08:54:12Z")\
**Posts on this page:** 1\
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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:** [July 2, 2024, 3:29am UTC](https://openfhe.discourse.group/t/ckks-bootstrapping-gives-incorrect-results-on-scale-60/844/6 "2024-07-02T03:29:17Z")

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> Does this imply that if I set firstMod = 60 and dcrtBits = 59, the message space is limited to 1 bit?

No, for the bootstrapping configuration, the message is automatically scaled down by 2^correctionfactor. The correction factor is found automatically by OpenFHE or can be manually set. The correction factor is typically between 7 and 13.

> But when i try to multiply c0=10 and c1=20 under this parameter, the decryption is still 200

For leveled CKKS, the extra RNS limbs/towers add support for numbers larger than 2^firstModulus/2^ScalingFactor. For example, if you reserve one extra limb, you will get extra 59 bits (you can support larger numbers in CKKS). But this logic does not apply to CKKS bootstrapping.

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