1 files changed, 39 insertions, 0 deletions

diff --git a/src/gnunet/crypto/gns_edkey_test.go b/src/gnunet/crypto/gns_edkey_test.go
index b5ba700..145bfab 100644
--- a/src/gnunet/crypto/gns_edkey_test.go
+++ b/src/gnunet/crypto/gns_edkey_test.go
@@ -22,7 +22,11 @@ import (
         "bytes"
         "encoding/hex"
         "gnunet/enums"
+        "gnunet/util"
         "testing"
+
+        "github.com/bfix/gospel/crypto/ed25519"
+        "github.com/bfix/gospel/math"
 )
 
 func TestEdKeyCreate(t *testing.T) {
@@ -58,3 +62,38 @@ func TestDeriveEDKEY(t *testing.T) {
                 t.Fatal("derive mismatch")
         }
 }
+
+// test 'DerivedSign' from LSD0001, 5.1.2. EDKEY
+func TestDerivedSign(t *testing.T) {
+
+        for i := 0; i < 20; i++ {
+                // generate clamped private scalar and keys (EdDSA)
+                a := util.NewRndArray(32)
+                a[31] &= 248
+                a[0] &= 127
+                a[0] |= 64
+                d := math.NewIntFromBytes(a)
+                zp := ed25519.NewPrivateKeyFromD(d)
+                zk := zp.Public()
+
+                // calculate blinding factor
+                h := math.NewIntRnd(ed25519N)
+
+                // derive keys
+                dzp := zp.Mult(h)
+                dzk := zk.Mult(h)
+                if !dzk.Q.Equals(dzp.Public().Q) {
+                        t.Fatal("derive")
+                }
+
+                // per draft:
+                a1 := d.Rsh(3)
+                a2 := h.Mul(a1).Mod(ed25519N)
+                dd := a2.Lsh(3)
+                dzp2 := ed25519.NewPrivateKeyFromD(dd)
+                dzk2 := dzp2.Public()
+                if !dzk.Q.Equals(dzk2.Q) {
+                        t.Fatal("mismatch")
+                }
+        }
+}