What’s is CKKS

Plain Computation Encrypted Computation
bool, int (uint 64), modulo p BGV, BFV, TFHE
double (float) CKKS

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Approximate arithmetic

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For floating-point arithmetic, we keep the bits of significand to be the same.

For fixed-point arithmetic, we keep the scaling factor to be the same.

Algorithms in CKKS

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Encoding and decoding

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在编码过程中需要使用比较大的scaling factor，这样可以保证更大的精度。

Encrypt and decrypt

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Ref

https://www.youtube.com/watch?v=iQlgeL64vfo