63 lines
2.0 KiB
Go
63 lines
2.0 KiB
Go
package keyer
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import (
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"context"
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"fiatjaf.com/nostr"
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"fiatjaf.com/nostr/nip44"
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"github.com/puzpuzpuz/xsync/v3"
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)
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var _ nostr.Keyer = (*KeySigner)(nil)
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// KeySigner is a signer that holds the private key in memory
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type KeySigner struct {
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sk [32]byte
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pk nostr.PubKey
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conversationKeys *xsync.MapOf[nostr.PubKey, [32]byte]
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}
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// NewPlainKeySigner creates a new KeySigner from a private key.
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// Returns an error if the private key is invalid.
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func NewPlainKeySigner(sec [32]byte) (KeySigner, error) {
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return KeySigner{sec, nostr.GetPublicKey(sec), xsync.NewMapOf[nostr.PubKey, [32]byte]()}, nil
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}
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// SignEvent signs the provided event with the signer's private key.
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// It sets the event's ID, PubKey, and Sig fields.
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func (ks KeySigner) SignEvent(ctx context.Context, evt *nostr.Event) error { return evt.Sign(ks.sk) }
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// GetPublicKey returns the public key associated with this signer.
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func (ks KeySigner) GetPublicKey(ctx context.Context) (nostr.PubKey, error) { return ks.pk, nil }
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// Encrypt encrypts a plaintext message for a recipient using NIP-44.
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// It caches conversation keys for efficiency in repeated operations.
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func (ks KeySigner) Encrypt(ctx context.Context, plaintext string, recipient nostr.PubKey) (string, error) {
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ck, ok := ks.conversationKeys.Load(recipient)
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if !ok {
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var err error
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ck, err = nip44.GenerateConversationKey(recipient, ks.sk)
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if err != nil {
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return "", err
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}
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ks.conversationKeys.Store(recipient, ck)
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}
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return nip44.Encrypt(plaintext, ck)
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}
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// Decrypt decrypts a base64-encoded ciphertext from a sender using NIP-44.
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// It caches conversation keys for efficiency in repeated operations.
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func (ks KeySigner) Decrypt(ctx context.Context, base64ciphertext string, sender nostr.PubKey) (string, error) {
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ck, ok := ks.conversationKeys.Load(sender)
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if !ok {
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var err error
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ck, err = nip44.GenerateConversationKey(sender, ks.sk)
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if err != nil {
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return "", err
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}
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ks.conversationKeys.Store(sender, ck)
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}
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return nip44.Decrypt(base64ciphertext, ck)
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}
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