nip17 and nip59.

nip59/nip59.go

@@ -0,0 +1,91 @@
+package nip59
+
+import (
+	"fmt"
+	"math/rand"
+
+	"github.com/mailru/easyjson"
+	"github.com/nbd-wtf/go-nostr"
+	"github.com/nbd-wtf/go-nostr/nip44"
+)
+
+// Seal takes a rumor, encrypts it and returns an unsigned 'seal' event, the 'seal' must be signed
+// afterwards.
+func Seal(rumor nostr.Event, encrypt func(string) (string, error)) (nostr.Event, error) {
+	rumor.Sig = ""
+	ciphertext, err := encrypt(rumor.String())
+
+	return nostr.Event{
+		Kind:      13,
+		Content:   ciphertext,
+		CreatedAt: nostr.Now() - nostr.Timestamp(60*rand.Int63n(600) /* up to 6 hours in the past */),
+		Tags:      make(nostr.Tags, 0),
+	}, err
+}
+
+// Takes a signed 'seal' and gift-wraps it using a random key, returns it signed.
+//
+// modify is a function that takes the gift-wrap before signing, can be used to apply
+// NIP-13 PoW or other things, otherwise can be nil.
+func GiftWrap(seal nostr.Event, recipientPublicKey string, modify func(*nostr.Event)) (nostr.Event, error) {
+	nonceKey := nostr.GeneratePrivateKey()
+	temporaryConversationKey, err := nip44.GenerateConversationKey(recipientPublicKey, nonceKey)
+	if err != nil {
+		return nostr.Event{}, err
+	}
+
+	ciphertext, err := nip44.Encrypt(seal.String(), temporaryConversationKey, nil)
+	if err != nil {
+		return nostr.Event{}, err
+	}
+
+	gw := nostr.Event{
+		Kind:      1059,
+		Content:   ciphertext,
+		CreatedAt: nostr.Now() - nostr.Timestamp(60*rand.Int63n(600) /* up to 6 hours in the past */),
+		Tags: nostr.Tags{
+			nostr.Tag{"p", recipientPublicKey},
+		},
+	}
+
+	// apply POW if necessary
+	if modify != nil {
+		modify(&gw)
+	}
+
+	err = gw.Sign(nonceKey)
+	return gw, nil
+}
+
+func GiftUnwrap(gw nostr.Event, decrypt func(string) (string, error)) (seal nostr.Event, err error) {
+	jevt, err := decrypt(gw.Content)
+	if err != nil {
+		return seal, err
+	}
+
+	err = easyjson.Unmarshal([]byte(jevt), &seal)
+	if err != nil {
+		return seal, err
+	}
+
+	if ok, _ := seal.CheckSignature(); !ok {
+		return seal, fmt.Errorf("seal signature is invalid")
+	}
+
+	return seal, nil
+}
+
+func Unseal(seal nostr.Event, decrypt func(string) (string, error)) (rumor nostr.Event, err error) {
+	jevt, err := decrypt(seal.Content)
+	if err != nil {
+		return rumor, err
+	}
+
+	err = easyjson.Unmarshal([]byte(jevt), &rumor)
+	if err != nil {
+		return rumor, err
+	}
+
+	rumor.PubKey = seal.PubKey
+	return rumor, nil
+}