diff options
| -rw-r--r-- | p2p/discover/node.go | 15 | ||||
| -rw-r--r-- | p2p/discover/node_test.go | 18 |
2 files changed, 33 insertions, 0 deletions
diff --git a/p2p/discover/node.go b/p2p/discover/node.go index c6d2e9766..de2588258 100644 --- a/p2p/discover/node.go +++ b/p2p/discover/node.go @@ -7,6 +7,7 @@ import ( "errors" "fmt" "io" + "math/big" "math/rand" "net" "net/url" @@ -14,6 +15,7 @@ import ( "strings" "time" + "github.com/ethereum/go-ethereum/crypto" "github.com/ethereum/go-ethereum/crypto/secp256k1" "github.com/ethereum/go-ethereum/rlp" ) @@ -187,6 +189,19 @@ func PubkeyID(pub *ecdsa.PublicKey) NodeID { return id } +// Pubkey returns the public key represented by the node ID. +// It returns an error if the ID is not a point on the curve. +func (id NodeID) Pubkey() (*ecdsa.PublicKey, error) { + p := &ecdsa.PublicKey{Curve: crypto.S256(), X: new(big.Int), Y: new(big.Int)} + half := len(id) / 2 + p.X.SetBytes(id[:half]) + p.Y.SetBytes(id[half:]) + if !p.Curve.IsOnCurve(p.X, p.Y) { + return nil, errors.New("not a point on the S256 curve") + } + return p, nil +} + // recoverNodeID computes the public key used to sign the // given hash from the signature. func recoverNodeID(hash, sig []byte) (id NodeID, err error) { diff --git a/p2p/discover/node_test.go b/p2p/discover/node_test.go index ae82ae4f1..60b01b6ca 100644 --- a/p2p/discover/node_test.go +++ b/p2p/discover/node_test.go @@ -133,6 +133,24 @@ func TestNodeID_recover(t *testing.T) { if pub != recpub { t.Errorf("recovered wrong pubkey:\ngot: %v\nwant: %v", recpub, pub) } + + ecdsa, err := pub.Pubkey() + if err != nil { + t.Errorf("Pubkey error: %v", err) + } + if !reflect.DeepEqual(ecdsa, &prv.PublicKey) { + t.Errorf("Pubkey mismatch:\n got: %#v\n want: %#v", ecdsa, &prv.PublicKey) + } +} + +func TestNodeID_pubkeyBad(t *testing.T) { + ecdsa, err := NodeID{}.Pubkey() + if err == nil { + t.Error("expected error for zero ID") + } + if ecdsa != nil { + t.Error("expected nil result") + } } func TestNodeID_distcmp(t *testing.T) { |