From 1d85452412b65e7976bc94969fc513ff6b880ed8 Mon Sep 17 00:00:00 2001
From: Werner Koch <wk@gnupg.org>
Date: Mon, 30 Sep 2013 21:14:11 +0200
Subject: ecc: Use faster b parameter for Ed25519.

* cipher/ecc-curves.c (domain_parms): Replace b.
* tests/t-mpi-point.c (test_curve): Ditto.
--

This change has been suggested by NIIBE Yutaka:

  Here,

    0x98412DFC9311D490018C7338BF8688861767FF8FF5B2BEBE27548A14B235EC8FEDA4

  is: (121666^-1 mod q)*121665.

  (121666^-1) * 121665 mod q is:

    0x2DFC9311D490018C7338BF8688861767FF8FF5B2BEBE27548A14B235ECA6874A

  While it works for both, I think that shorter is better.

Signed-off-by: Werner Koch <wk@gnupg.org>
---
 cipher/ecc-curves.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

(limited to 'cipher/ecc-curves.c')

diff --git a/cipher/ecc-curves.c b/cipher/ecc-curves.c
index 74473407..15888a8b 100644
--- a/cipher/ecc-curves.c
+++ b/cipher/ecc-curves.c
@@ -103,7 +103,7 @@ static const ecc_domain_parms_t domain_parms[] =
       MPI_EC_TWISTEDEDWARDS, ECC_DIALECT_ED25519,
       "0x7FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFED",
       "-0x01",
-      "-0x98412DFC9311D490018C7338BF8688861767FF8FF5B2BEBE27548A14B235EC8FEDA4",
+      "-0x2DFC9311D490018C7338BF8688861767FF8FF5B2BEBE27548A14B235ECA6874A",
       "0x1000000000000000000000000000000014DEF9DEA2F79CD65812631A5CF5D3ED",
       "0x216936D3CD6E53FEC0A4E231FDD6DC5C692CC7609525A7B2C9562D608F25D51A",
       "0x6666666666666666666666666666666666666666666666666666666666666658"
-- 
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