From ZmnSCPxj at protonmail.com  Wed Jun 26 05:18:26 2019
From: ZmnSCPxj at protonmail.com (ZmnSCPxj)
Date: Wed, 26 Jun 2019 05:18:26 +0000
Subject: [Lightning-dev] Proposal: Lightning Pre-Image Encryption
	Standard
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Good morning Stepan, and Nadav,

Both additions seem good idea to me.

> - Sally generates the invoice with the preimage `S` (i.e. x-coordinate of this point to make it 32-bytes long)

Does this require Bob to attempt both positive and negative sign for the y-coordinate?
Alternately we can force Sally to always use a scalar such that generated point has a fixed sign (or some other property to derive the sign of the missing coordinate).

Regards,
ZmnSCPxj