gift-wrap.

encrypt_decrypt.go

@@ -17,7 +17,7 @@ var encrypt = &cli.Command{
 		defaultKeyFlags,
 		&PubKeyFlag{
 			Name:     "recipient-pubkey",
-			Aliases:  []string{"p", "tgt", "target", "pubkey"},
+			Aliases:  []string{"p", "tgt", "target", "pubkey", "to"},
 			Required: true,
 		},
 		&cli.BoolFlag{
@@ -79,7 +79,7 @@ var decrypt = &cli.Command{
 		defaultKeyFlags,
 		&PubKeyFlag{
 			Name:     "sender-pubkey",
-			Aliases:  []string{"p", "src", "source", "pubkey"},
+			Aliases:  []string{"p", "src", "source", "pubkey", "from"},
 			Required: true,
 		},
 		&cli.BoolFlag{

gift.go

@@ -0,0 +1,192 @@
+package main
+
+import (
+	"context"
+	"fmt"
+	"math/rand"
+	"time"
+
+	"fiatjaf.com/nostr"
+	"fiatjaf.com/nostr/nip44"
+	"github.com/mailru/easyjson"
+	"github.com/urfave/cli/v3"
+)
+
+var gift = &cli.Command{
+	Name:  "gift",
+	Usage: "gift-wraps (or unwraps) an event according to NIP-59",
+	Description: `example:
+  nak event | nak gift wrap --sec <sec-a> -p <sec-b> | nak gift unwrap --sec <sec-b> --from <pub-a>`,
+	DisableSliceFlagSeparator: true,
+	Commands: []*cli.Command{
+		{
+			Name: "wrap",
+			Flags: append(
+				defaultKeyFlags,
+				&PubKeyFlag{
+					Name:     "recipient-pubkey",
+					Aliases:  []string{"p", "tgt", "target", "pubkey", "to"},
+					Required: true,
+				},
+			),
+			Usage: "turns an event into a rumor (unsigned) then gift-wraps it to the recipient",
+			Description: `example:
+  nak event -c 'hello' | nak gift wrap --sec <my-secret-key> -p <target-public-key>`,
+			Action: func(ctx context.Context, c *cli.Command) error {
+				kr, _, err := gatherKeyerFromArguments(ctx, c)
+				if err != nil {
+					return err
+				}
+
+				recipient := getPubKey(c, "recipient-pubkey")
+
+				// get sender pubkey
+				sender, err := kr.GetPublicKey(ctx)
+				if err != nil {
+					return fmt.Errorf("failed to get sender pubkey: %w", err)
+				}
+
+				// read event from stdin
+				for eventJSON := range getJsonsOrBlank() {
+					if eventJSON == "{}" {
+						continue
+					}
+
+					var originalEvent nostr.Event
+					if err := easyjson.Unmarshal([]byte(eventJSON), &originalEvent); err != nil {
+						return fmt.Errorf("invalid event JSON: %w", err)
+					}
+
+					// turn into rumor (unsigned event)
+					rumor := originalEvent
+					rumor.Sig = [64]byte{} // remove signature
+					rumor.PubKey = sender
+					rumor.ID = rumor.GetID() // compute ID
+
+					// create seal
+					rumorJSON, _ := easyjson.Marshal(rumor)
+					encryptedRumor, err := kr.Encrypt(ctx, string(rumorJSON), recipient)
+					if err != nil {
+						return fmt.Errorf("failed to encrypt rumor: %w", err)
+					}
+					seal := &nostr.Event{
+						Kind:      13,
+						Content:   encryptedRumor,
+						PubKey:    sender,
+						CreatedAt: randomNow(),
+						Tags:      nostr.Tags{},
+					}
+					if err := kr.SignEvent(ctx, seal); err != nil {
+						return fmt.Errorf("failed to sign seal: %w", err)
+					}
+
+					// create gift wrap
+					ephemeral := nostr.Generate()
+					sealJSON, _ := easyjson.Marshal(seal)
+					convkey, err := nip44.GenerateConversationKey(recipient, ephemeral)
+					if err != nil {
+						return fmt.Errorf("failed to generate conversation key: %w", err)
+					}
+					encryptedSeal, err := nip44.Encrypt(string(sealJSON), convkey)
+					if err != nil {
+						return fmt.Errorf("failed to encrypt seal: %w", err)
+					}
+					wrap := &nostr.Event{
+						Kind:      1059,
+						Content:   encryptedSeal,
+						CreatedAt: randomNow(),
+						Tags:      nostr.Tags{{"p", recipient.Hex()}},
+					}
+					wrap.Sign(ephemeral)
+
+					// print the gift-wrap
+					wrapJSON, err := easyjson.Marshal(wrap)
+					if err != nil {
+						return fmt.Errorf("failed to marshal gift wrap: %w", err)
+					}
+					stdout(string(wrapJSON))
+				}
+
+				return nil
+			},
+		},
+		{
+			Name:  "unwrap",
+			Usage: "decrypts a gift-wrap event sent by the sender to us and exposes its internal rumor (unsigned event).",
+			Description: `example:
+  nak req -p <my-public-key> -k 1059 dmrelay.com | nak gift unwrap --sec <my-secret-key> --from <sender-public-key>`,
+			Flags: append(
+				defaultKeyFlags,
+				&PubKeyFlag{
+					Name:     "sender-pubkey",
+					Aliases:  []string{"p", "src", "source", "pubkey", "from"},
+					Required: true,
+				},
+			),
+			Action: func(ctx context.Context, c *cli.Command) error {
+				kr, _, err := gatherKeyerFromArguments(ctx, c)
+				if err != nil {
+					return err
+				}
+
+				sender := getPubKey(c, "sender-pubkey")
+
+				// read gift-wrapped event from stdin
+				for wrapJSON := range getJsonsOrBlank() {
+					if wrapJSON == "{}" {
+						continue
+					}
+
+					var wrap nostr.Event
+					if err := easyjson.Unmarshal([]byte(wrapJSON), &wrap); err != nil {
+						return fmt.Errorf("invalid gift wrap JSON: %w", err)
+					}
+
+					if wrap.Kind != 1059 {
+						return fmt.Errorf("not a gift wrap event (kind %d)", wrap.Kind)
+					}
+
+					ephemeralPubkey := wrap.PubKey
+
+					// decrypt seal
+					sealJSON, err := kr.Decrypt(ctx, wrap.Content, ephemeralPubkey)
+					if err != nil {
+						return fmt.Errorf("failed to decrypt seal: %w", err)
+					}
+
+					var seal nostr.Event
+					if err := easyjson.Unmarshal([]byte(sealJSON), &seal); err != nil {
+						return fmt.Errorf("invalid seal JSON: %w", err)
+					}
+
+					if seal.Kind != 13 {
+						return fmt.Errorf("not a seal event (kind %d)", seal.Kind)
+					}
+
+					// decrypt rumor
+					rumorJSON, err := kr.Decrypt(ctx, seal.Content, sender)
+					if err != nil {
+						return fmt.Errorf("failed to decrypt rumor: %w", err)
+					}
+
+					var rumor nostr.Event
+					if err := easyjson.Unmarshal([]byte(rumorJSON), &rumor); err != nil {
+						return fmt.Errorf("invalid rumor JSON: %w", err)
+					}
+
+					// output the unwrapped event (rumor)
+					stdout(rumorJSON)
+				}
+
+				return nil
+			},
+		},
+	},
+}
+
+func randomNow() nostr.Timestamp {
+	const twoDays = 2 * 24 * 60 * 60
+	now := time.Now().Unix()
+	randomOffset := rand.Int63n(twoDays)
+	return nostr.Timestamp(now - randomOffset)
+}

main.go

@@ -42,6 +42,7 @@ var app = &cli.Command{
 		blossomCmd,
 		encrypt,
 		decrypt,
+		gift,
 		outbox,
 		wallet,
 		mcpServer,