remove in metadata cid_* to put in the cids/ set

internal/identity/identity_test.go

@@ -0,0 +1,203 @@
+package identity
+
+import (
+	"crypto/sha256"
+	"encoding/hex"
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+
+	"github.com/decred/dcrd/dcrec/secp256k1/v4"
+	"github.com/decred/dcrd/dcrec/secp256k1/v4/ecdsa"
+)
+
+func TestGenerateUIDIsDeterministicFromPubkey(t *testing.T) {
+	id, err := Generate()
+	if err != nil {
+		t.Fatalf("generate: %v", err)
+	}
+	if !strings.HasPrefix(id.UID, "z") {
+		t.Fatalf("uid missing multibase 'z' prefix: %q", id.UID)
+	}
+	if id.Curve != CurveSecp256k1 {
+		t.Fatalf("curve = %q", id.Curve)
+	}
+	if len(id.PrivateKeyHex) != 64 {
+		t.Fatalf("privkey hex len = %d", len(id.PrivateKeyHex))
+	}
+	if len(id.PublicKeyHex) != 66 {
+		t.Fatalf("compressed pubkey hex len = %d", len(id.PublicKeyHex))
+	}
+
+	// Reimporting yields the same uid.
+	imported, err := Import(id.PrivateKeyHex)
+	if err != nil {
+		t.Fatalf("import: %v", err)
+	}
+	if imported.UID != id.UID {
+		t.Fatalf("uid changed after import roundtrip: %q vs %q", id.UID, imported.UID)
+	}
+	if imported.PublicKeyHex != id.PublicKeyHex {
+		t.Fatalf("pubkey changed after import roundtrip")
+	}
+}
+
+func TestImportRejectsBadInput(t *testing.T) {
+	if _, err := Import(""); err == nil {
+		t.Fatal("empty hex should error")
+	}
+	if _, err := Import("zz"); err == nil {
+		t.Fatal("non-hex should error")
+	}
+	if _, err := Import("00"); err == nil {
+		t.Fatal("wrong-length hex should error")
+	}
+	if _, err := Import(strings.Repeat("00", 32)); err == nil {
+		t.Fatal("zero scalar should error")
+	}
+	// Hex with 0x prefix should work.
+	id1, err := Generate()
+	if err != nil {
+		t.Fatal(err)
+	}
+	id2, err := Import("0x" + id1.PrivateKeyHex)
+	if err != nil {
+		t.Fatalf("0x-prefixed hex: %v", err)
+	}
+	if id1.UID != id2.UID {
+		t.Fatal("uid mismatch through 0x prefix")
+	}
+}
+
+func TestSaveLoadRoundtrip(t *testing.T) {
+	dir := t.TempDir()
+	path := filepath.Join(dir, "identity.json")
+
+	if Exists(path) {
+		t.Fatal("file should not exist yet")
+	}
+	if got, _ := Load(path); got != nil {
+		t.Fatal("Load on missing file should return nil")
+	}
+
+	id, err := Generate()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if err := Save(path, id); err != nil {
+		t.Fatal(err)
+	}
+	if !Exists(path) {
+		t.Fatal("file should exist after Save")
+	}
+
+	loaded, err := Load(path)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if loaded == nil || loaded.UID != id.UID || loaded.PrivateKeyHex != id.PrivateKeyHex {
+		t.Fatalf("roundtrip mismatch: %+v vs %+v", id, loaded)
+	}
+
+	// File should be 0600 (private key on disk).
+	info, err := os.Stat(path)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if info.Mode().Perm() != 0600 {
+		t.Errorf("identity file mode = %o, want 0600", info.Mode().Perm())
+	}
+
+	if err := Delete(path); err != nil {
+		t.Fatal(err)
+	}
+	if Exists(path) {
+		t.Fatal("file should not exist after Delete")
+	}
+	// Delete is idempotent.
+	if err := Delete(path); err != nil {
+		t.Fatalf("Delete on missing file should be nil: %v", err)
+	}
+}
+
+func TestSignAndVerify(t *testing.T) {
+	id, err := Generate()
+	if err != nil {
+		t.Fatal(err)
+	}
+	msg := []byte("hello user data layer")
+	sig, err := Sign(id, msg)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(sig) == 0 {
+		t.Fatal("empty sig")
+	}
+
+	// Verify externally with the public key, matching what meta-watch will do.
+	pubBytes, err := hex.DecodeString(id.PublicKeyHex)
+	if err != nil {
+		t.Fatal(err)
+	}
+	pub, err := secp256k1.ParsePubKey(pubBytes)
+	if err != nil {
+		t.Fatal(err)
+	}
+	parsedSig, err := ecdsa.ParseDERSignature(sig)
+	if err != nil {
+		t.Fatalf("parse DER sig: %v", err)
+	}
+	digest := sha256.Sum256(msg)
+	if !parsedSig.Verify(digest[:], pub) {
+		t.Fatal("signature did not verify")
+	}
+
+	// Flipping a byte must break verification.
+	tampered := append([]byte{}, msg...)
+	tampered[0] ^= 0x01
+	digest2 := sha256.Sum256(tampered)
+	if parsedSig.Verify(digest2[:], pub) {
+		t.Fatal("signature verified on tampered message")
+	}
+}
+
+func TestDeriveAEADKeyIsDeterministic(t *testing.T) {
+	id, err := Generate()
+	if err != nil {
+		t.Fatal(err)
+	}
+	k1, err := DeriveAEADKey(id)
+	if err != nil {
+		t.Fatal(err)
+	}
+	k2, err := DeriveAEADKey(id)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !bytesEqual(k1, k2) {
+		t.Fatal("AEAD key derivation is non-deterministic")
+	}
+	if len(k1) != aeadKeyLen {
+		t.Fatalf("AEAD key len = %d, want %d", len(k1), aeadKeyLen)
+	}
+
+	// Different identity → different key.
+	other, _ := Generate()
+	k3, _ := DeriveAEADKey(other)
+	if bytesEqual(k1, k3) {
+		t.Fatal("two distinct identities derived the same AEAD key")
+	}
+}
+
+func bytesEqual(a, b []byte) bool {
+	if len(a) != len(b) {
+		return false
+	}
+	for i := range a {
+		if a[i] != b[i] {
+			return false
+		}
+	}
+	return true
+}