diff --git a/nip04/nip04.go b/nip04/nip04.go
index 1923cd6..fc4cca5 100644
--- a/nip04/nip04.go
+++ b/nip04/nip04.go
@@ -13,16 +13,18 @@ import (
 	"github.com/btcsuite/btcd/btcec/v2"
 )
 
-// ECDH
-func ComputeSharedSecret(senderPrivKey string, receiverPubKey string) (sharedSecret []byte, err error) {
-	privKeyBytes, err := hex.DecodeString(senderPrivKey)
+// ComputeSharedSecret returns a shared secret key used to encrypt messages.
+// The private and public keys should be hex encoded.
+// Uses the Diffie-Hellman key exchange (ECDH) (RFC 4753).
+func ComputeSharedSecret(pub string, sk string) (sharedSecret []byte, err error) {
+	privKeyBytes, err := hex.DecodeString(sk)
 	if err != nil {
 		return nil, fmt.Errorf("Error decoding sender private key: %s. \n", err)
 	}
 	privKey, _ := btcec.PrivKeyFromBytes(privKeyBytes)
 
 	// adding 02 to signal that this is a compressed public key (33 bytes)
-	pubKeyBytes, err := hex.DecodeString("02" + receiverPubKey)
+	pubKeyBytes, err := hex.DecodeString("02" + pub)
 	if err != nil {
 		return nil, fmt.Errorf("Error decoding hex string of receiver public key: %s. \n", err)
 	}
@@ -34,7 +36,9 @@ func ComputeSharedSecret(senderPrivKey string, receiverPubKey string) (sharedSec
 	return btcec.GenerateSharedSecret(privKey, pubKey), nil
 }
 
-// aes-256-cbc
+// Encrypt encrypts message with key using aes-256-cbc.
+// key should be the shared secret generated by ComputeSharedSecret.
+// Returns: base64(encrypted_bytes) + "?iv=" + base64(initialization_vector).
 func Encrypt(message string, key []byte) (string, error) {
 	// block size is 16 bytes
 	iv := make([]byte, 16)
@@ -70,7 +74,8 @@ func Encrypt(message string, key []byte) (string, error) {
 	return base64.StdEncoding.EncodeToString(ciphertext) + "?iv=" + base64.StdEncoding.EncodeToString(iv), nil
 }
 
-// aes-256-cbc
+// Decrypt decrypts a content string using the shared secret key.
+// The inverse operation to message -> Encrypt(message, key).
 func Decrypt(content string, key []byte) (string, error) {
 	parts := strings.Split(content, "?iv=")
 	if len(parts) < 2 {