<html><body><span class="xfm_00817772">Hello, Messaging!<br/><br/>I'm trying to adapt Elligator2 p2r() to the uNaCl X25519 library for embedded systems. <br/>The original p2r() uses the sign(v) to select between sqrt(-u/(2(u+A))) and sqrt(-(u+A)/(2u))) . <br/>But X25519 point has no v ( sign(v) is always assumed to be 0 ). <br/>Can I use sign(v)=0 or must select the sign(v) randomly to get a completely random representation string of X25519 u-point with p2r()?<br/><br/>Thanks, <br/>Van Gegel.<br/></span></body></html>