keyer, nip17, nip44, nip59: this time is different!

keyer/lib.go

@@ -12,6 +12,7 @@ import (
 	"github.com/nbd-wtf/go-nostr/nip19"
 	"github.com/nbd-wtf/go-nostr/nip46"
 	"github.com/nbd-wtf/go-nostr/nip49"
+	"github.com/puzpuzpuz/xsync/v3"
 )
 
 type Keyer interface {
@@ -61,7 +62,7 @@ func New(ctx context.Context, pool *nostr.SimplePool, input string, opts *Signer
 			return nil, fmt.Errorf("failed to decrypt with given password: %w", err)
 		}
 		pk, _ := nostr.GetPublicKey(sec)
-		return KeySigner{sec, pk, make(map[string][32]byte)}, nil
+		return KeySigner{sec, pk, xsync.NewMapOf[string, [32]byte]()}, nil
 	} else if nip46.IsValidBunkerURL(input) || nip05.IsValidIdentifier(input) {
 		bcsk := nostr.GeneratePrivateKey()
 		oa := func(url string) { println("auth_url received but not handled") }
@@ -81,11 +82,11 @@ func New(ctx context.Context, pool *nostr.SimplePool, input string, opts *Signer
 	} else if prefix, parsed, err := nip19.Decode(input); err == nil && prefix == "nsec" {
 		sec := parsed.(string)
 		pk, _ := nostr.GetPublicKey(sec)
-		return KeySigner{sec, pk, make(map[string][32]byte)}, nil
+		return KeySigner{sec, pk, xsync.NewMapOf[string, [32]byte]()}, nil
 	} else if _, err := hex.DecodeString(input); err == nil && len(input) < 64 {
 		input = strings.Repeat("0", 64-len(input)) + input // if the key is like '01', fill all the left zeroes
 		pk, _ := nostr.GetPublicKey(input)
-		return KeySigner{input, pk, make(map[string][32]byte)}, nil
+		return KeySigner{input, pk, xsync.NewMapOf[string, [32]byte]()}, nil
 	}
 
 	return nil, fmt.Errorf("unsupported input '%s'", input)

keyer/plain.go

@@ -5,41 +5,42 @@ import (
 
 	"github.com/nbd-wtf/go-nostr"
 	"github.com/nbd-wtf/go-nostr/nip44"
+	"github.com/puzpuzpuz/xsync/v3"
 )
 
 // Keysigner is a signer that holds the private key in memory and can do all the operations instantly and easily.
 type KeySigner struct {
 	sk string
 	pk string
 
-	conversationKeys map[string][32]byte
+	conversationKeys *xsync.MapOf[string, [32]byte]
 }
 
 func (ks KeySigner) SignEvent(ctx context.Context, evt *nostr.Event) error { return evt.Sign(ks.sk) }
 func (ks KeySigner) GetPublicKey(ctx context.Context) string               { return ks.pk }
 
 func (ks KeySigner) Encrypt(ctx context.Context, plaintext string, recipient string) (string, error) {
-	ck, ok := ks.conversationKeys[recipient]
+	ck, ok := ks.conversationKeys.Load(recipient)
 	if !ok {
 		var err error
 		ck, err = nip44.GenerateConversationKey(recipient, ks.sk)
 		if err != nil {
 			return "", err
 		}
-		ks.conversationKeys[recipient] = ck
+		ks.conversationKeys.Store(recipient, ck)
 	}
 	return nip44.Encrypt(plaintext, ck)
 }
 
 func (ks KeySigner) Decrypt(ctx context.Context, base64ciphertext string, sender string) (string, error) {
-	ck, ok := ks.conversationKeys[sender]
+	ck, ok := ks.conversationKeys.Load(sender)
 	if !ok {
 		var err error
 		ck, err = nip44.GenerateConversationKey(sender, ks.sk)
 		if err != nil {
 			return "", err
 		}
-		ks.conversationKeys[sender] = ck
+		ks.conversationKeys.Store(sender, ck)
 	}
 	return nip44.Decrypt(base64ciphertext, ck)
 }

nip17/nip17.go

@@ -49,9 +49,20 @@ func PrepareMessage(
 	}
 	rumor.ID = rumor.GetID()
 
-	wraps, err := nip59.GiftWrap(
+	toUs, err = nip59.GiftWrap(
 		rumor,
-		[]string{ourPubkey, recipientPubKey},
+		ourPubkey,
+		func(s string) (string, error) { return kr.Encrypt(ctx, s, ourPubkey) },
+		func(e *nostr.Event) error { return kr.SignEvent(ctx, e) },
+		modify,
+	)
+	if err != nil {
+		return nostr.Event{}, nostr.Event{}, err
+	}
+
+	toThem, err = nip59.GiftWrap(
+		rumor,
+		ourPubkey,
 		func(s string) (string, error) { return kr.Encrypt(ctx, s, recipientPubKey) },
 		func(e *nostr.Event) error { return kr.SignEvent(ctx, e) },
 		modify,
@@ -60,7 +71,7 @@ func PrepareMessage(
 		return nostr.Event{}, nostr.Event{}, err
 	}
 
-	return wraps[0], wraps[1], nil
+	return toUs, toThem, nil
 }
 
 // ListenForMessages returns a channel with the rumors already decrypted and checked

nip44/nip44.go

@@ -58,7 +58,7 @@ func Encrypt(plaintext string, conversationKey [32]byte, applyOptions ...func(op
 		}
 	}
 
-	enc, cc20nonce, auth, err := messageKeys(conversationKey, nonce)
+	cc20key, cc20nonce, hmackey, err := messageKeys(conversationKey, nonce)
 	if err != nil {
 		return "", err
 	}
@@ -74,12 +74,12 @@ func Encrypt(plaintext string, conversationKey [32]byte, applyOptions ...func(op
 	binary.BigEndian.PutUint16(padded, uint16(size))
 	copy(padded[2:], plain)
 
-	ciphertext, err := chacha(enc, cc20nonce, []byte(padded))
+	ciphertext, err := chacha(cc20key, cc20nonce, []byte(padded))
 	if err != nil {
 		return "", err
 	}
 
-	mac, err := sha256Hmac(auth, ciphertext, nonce)
+	mac, err := sha256Hmac(hmackey, ciphertext, nonce)
 	if err != nil {
 		return "", err
 	}
@@ -120,12 +120,12 @@ func Decrypt(b64ciphertextWrapped string, conversationKey [32]byte) (string, err
 	copy(nonce[:], decoded[1:33])
 	ciphertext := decoded[33 : dLen-32]
 	givenMac := decoded[dLen-32:]
-	enc, cc20nonce, auth, err := messageKeys(conversationKey, nonce)
+	cc20key, cc20nonce, hmackey, err := messageKeys(conversationKey, nonce)
 	if err != nil {
 		return "", err
 	}
 
-	expectedMac, err := sha256Hmac(auth, ciphertext, nonce)
+	expectedMac, err := sha256Hmac(hmackey, ciphertext, nonce)
 	if err != nil {
 		return "", err
 	}
@@ -134,7 +134,7 @@ func Decrypt(b64ciphertextWrapped string, conversationKey [32]byte) (string, err
 		return "", fmt.Errorf("invalid hmac")
 	}
 
-	padded, err := chacha(enc, cc20nonce, ciphertext)
+	padded, err := chacha(cc20key, cc20nonce, ciphertext)
 	if err != nil {
 		return "", err
 	}
@@ -191,8 +191,9 @@ func sha256Hmac(key []byte, ciphertext []byte, nonce [32]byte) ([]byte, error) {
 
 func messageKeys(conversationKey [32]byte, nonce [32]byte) ([]byte, []byte, []byte, error) {
 	r := hkdf.Expand(sha256.New, conversationKey[:], nonce[:])
-	enc := make([]byte, 32)
-	if _, err := io.ReadFull(r, enc); err != nil {
+
+	cc20key := make([]byte, 32)
+	if _, err := io.ReadFull(r, cc20key); err != nil {
 		return nil, nil, nil, err
 	}
 
@@ -201,12 +202,12 @@ func messageKeys(conversationKey [32]byte, nonce [32]byte) ([]byte, []byte, []by
 		return nil, nil, nil, err
 	}
 
-	auth := make([]byte, 32)
-	if _, err := io.ReadFull(r, auth); err != nil {
+	hmacKey := make([]byte, 32)
+	if _, err := io.ReadFull(r, hmacKey); err != nil {
 		return nil, nil, nil, err
 	}
 
-	return enc, cc20nonce, auth, nil
+	return cc20key, cc20nonce, hmacKey, nil
 }
 
 func calcPadding(sLen int) int {

nip59/nip59.go

@@ -9,19 +9,20 @@ import (
 	"github.com/nbd-wtf/go-nostr/nip44"
 )
 
-// Seal takes a 'rumor', encrypts it with our own key, making a 'seal', then encrypts that with a nonce key and
+// GiftWrap takes a 'rumor', encrypts it with our own key, making a 'seal', then encrypts that with a nonce key and
 // signs that (after potentially applying a modify function, which can be nil otherwise), yielding a 'gift-wrap'.
 func GiftWrap(
 	rumor nostr.Event,
-	recipients []string, // return one giftwrap addressed to each of these
+	recipient string,
 	encrypt func(plaintext string) (string, error),
 	sign func(*nostr.Event) error,
 	modify func(*nostr.Event),
-) ([]nostr.Event, error) {
+) (nostr.Event, error) {
 	rumor.Sig = ""
+
 	rumorCiphertext, err := encrypt(rumor.String())
 	if err != nil {
-		return nil, err
+		return nostr.Event{}, err
 	}
 
 	seal := nostr.Event{
@@ -31,39 +32,36 @@ func GiftWrap(
 		Tags:      make(nostr.Tags, 0),
 	}
 	if err := sign(&seal); err != nil {
-		return nil, err
+		return nostr.Event{}, err
+	}
+
+	nonceKey := nostr.GeneratePrivateKey()
+	temporaryConversationKey, err := nip44.GenerateConversationKey(recipient, nonceKey)
+	if err != nil {
+		return nostr.Event{}, err
+	}
+
+	sealCiphertext, err := nip44.Encrypt(seal.String(), temporaryConversationKey)
+	if err != nil {
+		return nostr.Event{}, err
 	}
 
-	results := make([]nostr.Event, len(recipients))
-	for i, recipient := range recipients {
-		nonceKey := nostr.GeneratePrivateKey()
-		temporaryConversationKey, err := nip44.GenerateConversationKey(recipient, nonceKey)
-		if err != nil {
-			return nil, err
-		}
-		sealCiphertext, err := nip44.Encrypt(seal.String(), temporaryConversationKey)
-		if err != nil {
-			return nil, err
-		}
-
-		gw := nostr.Event{
-			Kind:      1059,
-			Content:   sealCiphertext,
-			CreatedAt: nostr.Now() - nostr.Timestamp(60*rand.Int63n(600) /* up to 6 hours in the past */),
-			Tags: nostr.Tags{
-				nostr.Tag{"p", recipient},
-			},
-		}
-		if modify != nil {
-			modify(&gw)
-		}
-		if err := gw.Sign(nonceKey); err != nil {
-			return nil, err
-		}
-		results[i] = gw
+	gw := nostr.Event{
+		Kind:      1059,
+		Content:   sealCiphertext,
+		CreatedAt: nostr.Now() - nostr.Timestamp(60*rand.Int63n(600) /* up to 6 hours in the past */),
+		Tags: nostr.Tags{
+			nostr.Tag{"p", recipient},
+		},
+	}
+	if modify != nil {
+		modify(&gw)
+	}
+	if err := gw.Sign(nonceKey); err != nil {
+		return nostr.Event{}, err
 	}
 
-	return results, nil
+	return gw, nil
 }
 
 func GiftUnwrap(