diff --git a/lib/nostr.dart b/lib/nostr.dart
index 5bc4d95..2176da7 100644
--- a/lib/nostr.dart
+++ b/lib/nostr.dart
@@ -11,4 +11,4 @@ export 'src/close.dart';
 export 'src/message.dart';
 export 'src/utils.dart';
 export 'src/nips/nip_002.dart';
-export 'src/nips/nip_004/event.dart';
+export 'src/nips/nip_004.dart';
diff --git a/lib/src/nips/nip_004/crypto.dart b/lib/src/crypto/nip_004.dart
similarity index 98%
rename from lib/src/nips/nip_004/crypto.dart
rename to lib/src/crypto/nip_004.dart
index 73385b4..6e49ae7 100644
--- a/lib/src/nips/nip_004/crypto.dart
+++ b/lib/src/crypto/nip_004.dart
@@ -5,7 +5,7 @@ import 'package:nostr/src/crypto/kepler.dart';
 import 'package:pointycastle/export.dart';
 
 /// NIP4 cipher
-String cipher(
+String nip4cipher(
   String privkey,
   String pubkey,
   String payload,
diff --git a/lib/src/nips/nip_004/event.dart b/lib/src/nips/nip_004.dart
similarity index 95%
rename from lib/src/nips/nip_004/event.dart
rename to lib/src/nips/nip_004.dart
index c76a951..aec1fc4 100644
--- a/lib/src/nips/nip_004/event.dart
+++ b/lib/src/nips/nip_004.dart
@@ -1,11 +1,11 @@
 import 'package:bip340/bip340.dart' as bip340;
 import 'package:nostr/src/event.dart';
-import 'package:nostr/src/nips/nip_004/crypto.dart';
+import 'package:nostr/src/crypto/nip_004.dart';
 import 'package:nostr/src/utils.dart';
 
 /// A special event with kind 4, meaning "encrypted direct message".
 ///
-/// content MUST be equal to the base64-encoded, aes-256-cbc encrypted string of anything a user wants to write, encrypted using a shared cipher generated by combining the recipient's public-key with the sender's private-key;
+/// content MUST be equal to the base64-encoded, aes-256-cbc encrypted string of anything a user wants to write, encrypted using a shared nip4cipher generated by combining the recipient's public-key with the sender's private-key;
 /// this appended by the base64-encoded initialization vector as if it was a querystring parameter named "iv".
 /// The format is the following: "content": "<encrypted_text>?iv=<initialization_vector>".
 ///
@@ -58,7 +58,7 @@ class EncryptedDirectMessage extends Event {
       tags: [
         ['p', receiverPubkey]
       ],
-      content: cipher(
+      content: nip4cipher(
         senderPrivkey,
         '02$receiverPubkey',
         message,
@@ -87,7 +87,7 @@ class EncryptedDirectMessage extends Event {
     String ciphertext = content.split("?iv=")[0];
     String plaintext;
     try {
-      plaintext = cipher(
+      plaintext = nip4cipher(
         privkey,
         "02$pubkey",
         ciphertext,