Jeremy Spilman [ARCHIVE] on Nostr: 📅 Original date posted:2014-01-14 📝 Original message:On Tue, 14 Jan 2014 ...

📅 Original date posted:2014-01-14
📝 Original message:On Tue, 14 Jan 2014 13:51:06 -0800, Adam Back <adam at cypherspace.org> wrote:
> I saw in the math version you had said Q'=Q+H(S) and I presumed it was a
> typo, but your code says the same thing. I presume you meant Q'=Q+H(S)*G
> and therefore that Util.SingleSHA256() multiplies by G internally?
>
> Adam
>

Thanks for reviewing this. The relevant line:

byte[] q1New = EC.PointAdd(Q1, Util.SingleSHA256(S1));

SingleSHA256 is a single application of SHA256 -- named so since 'SHA256'
functions in many Bitcoin libraries too often actually run DoubleSHA256.
32 bytes are returned.

The multiplication by 'G' that you mention is part of my EC.PointAdd...

I should probably just publish all my code as MIT and be done with it ;-)

Thanks,
Jeremy


public static byte[] PointAdd(byte[] point, byte[] scalar, bool compressed
= true)
{
var point1 = new OpenSSL.Crypto.EC.Point(EcGroup, point);

var num = OpenSSL.Core.BigNumber.FromArray(scalar);
var point2 = OpenSSL.Crypto.EC.Point.Multiply(EcGroup, num,
EcBnContext);

var result = point1.Add(point2, EcBnContext);

if (compressed)
return result.GetBytes(ConversionForm.Compressed);
else
return result.GetBytes(ConversionForm.Uncompressed);
}