How to perform point subtraction and negation on BLS curve?

[Qiao-Jin]

Hello! I'm curious how to perform point subtraction and negation on BLS curve. I.e there are two signatures A and B, how to perform point subtraction & negation such as A - B, -B, etc in this repo? Thx!

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I observed that this func might be used for signature subtraction:

https://github.com/herumi/bls/blob/3f3850a6eac71e1ce31b4a3d9b85aa7af2a2d08e/src/bls_c_impl.hpp#L859

Could you please include this func into https://github.com/herumi/bls/blob/master/ffi/cs/bls.cs? Thx!

[Qiao-Jin]

@herumi

[herumi]

Do you want the function from C#?

[Qiao-Jin]

Do you want the function from C#?

Yes, it's needed for subtraction between signatures

[herumi]

Okay, I'll append it. Please wait a moment.

[Qiao-Jin]

Okay, I'll append it. Please wait a moment.

Thx so much!

[herumi]

I added sub methods. https://github.com/herumi/bls/commit/98140f3d8efe2d7b99ca971461a0a99d08304903

Though neg(X) can be achieved using sub(zero, X), do you need neg?

[Qiao-Jin]

I added sub methods. 98140f3

Though neg(X) can be achieved using sub(zero, X), do you need neg?

I think that should be enough, thx! By the way, if B = 3A, is there a way to get A from B?

[herumi]

What are the types of A and B?

[Qiao-Jin]

What are the types of A and B?

They are signatures

[herumi]

I'm sorry for the late response. I added them about one month ago.