Merge pull request #5 from spacemeshos/remove-key-derivation

Remove key derivation function from ed25519-recovery

ed25519.go

@@ -8,7 +8,6 @@ import (
 	"bytes"
 	"crypto/ed25519"
 	"crypto/sha512"
-	"encoding/binary"
 	"errors"
 	"io"
 	"strconv"
@@ -47,23 +46,6 @@ func NewKeyFromSeed(seed []byte) PrivateKey {
 	return ed25519.NewKeyFromSeed(seed)
 }
 
-// NewDerivedKeyFromSeed calculates a private key from a 32 bytes random seed,
-// an integer index and salt.
-func NewDerivedKeyFromSeed(seed []byte, index uint64, salt []byte) PrivateKey {
-	if l := len(seed); l != SeedSize {
-		panic("ed25519: bad seed length: " + strconv.Itoa(l))
-	}
-
-	digest := sha512.New()
-	digest.Write(seed)
-	digest.Write(salt)
-	buf := make([]byte, 8)
-	binary.LittleEndian.PutUint64(buf, index)
-	digest.Write(buf)
-
-	return NewKeyFromSeed(digest.Sum(nil)[:SeedSize])
-}
-
 // ExtractPublicKey extracts the signer's public key given a message and its
 // signature. It will panic if len(sig) is not [SignatureSize].
 //

ed25519_fuzz_test.go

@@ -60,28 +60,3 @@ func Fuzz_Sign(f *testing.F) {
 		require.EqualValues(t, key.Public(), pub)
 	})
 }
-
-func Fuzz_Derive(f *testing.F) {
-	py, err := pure25519.New()
-	if err != nil {
-		f.Skip("failed to initialize python bindings")
-	}
-
-	f.Add(int64(0), []byte("Spacemesh rocks"), uint64(5))
-	f.Fuzz(func(t *testing.T, rndSeed int64, salt []byte, index uint64) {
-		src := rand.New(rand.NewSource(rndSeed))
-		seed := make([]byte, 32)
-
-		// generate random seed
-		_, err := src.Read(seed)
-		require.NoError(t, err, "failed to read random seed")
-
-		// derive key from seed
-		goKey := NewDerivedKeyFromSeed(seed, index, salt)
-		pyKey, err := py.Derive(seed, salt, index)
-		require.NoError(t, err)
-
-		// compare keys
-		require.EqualValues(t, pyKey, goKey.Seed())
-	})
-}

ed25519_test.go

@@ -4,7 +4,6 @@
 package ed25519
 
 import (
-	"encoding/hex"
 	"testing"
 
 	"github.com/stretchr/testify/require"
@@ -56,13 +55,3 @@ func Test_SignVerify(t *testing.T) {
 	wrongMessage := []byte("wrong message")
 	require.False(t, Verify(public, wrongMessage, sig), "signature of different message accepted")
 }
-
-func Test_Derive(t *testing.T) {
-	const expectedEncodedKey = "b6e1caa7ed8fb8b517dbbd5a49f7c9e76f33f0dd74100396207b640479d6fade2b0f080a354fd3c981630efe75bcbc5f4134895b749364f25badeae5a687950c"
-	const s = "8d03a58456bb1b45f696032444b09d476fa5406f998ed0a50e694ee8a40cfb09"
-	seed, err := hex.DecodeString(s)
-	require.NoError(t, err)
-
-	privateKey1 := NewDerivedKeyFromSeed(seed, 5, []byte("Spacemesh rocks"))
-	require.Equal(t, expectedEncodedKey, hex.EncodeToString(privateKey1), "Unexpected key")
-}