From c78bd4cef11d76fd5aa1add31e42cbdc5da1c6ea Mon Sep 17 00:00:00 2001
From: fiatjaf <fiatjaf@gmail.com>
Date: Tue, 15 Aug 2023 11:40:54 -0300
Subject: [PATCH] encoding implementation doesn't require complicate TLV
 parsing.

---
 44.md | 46 +++++++++++++---------------------------------
 1 file changed, 13 insertions(+), 33 deletions(-)

diff --git a/44.md b/44.md
index 1ff5a8a1..da840593 100644
--- a/44.md
+++ b/44.md
@@ -30,7 +30,7 @@ Example:
 Encrypting the message `hello` from Alice to Bob results in the base-64 encoded tlv payload:
 
 ```
-AAEBARgeI8gcP/4mnw3mKgtMvD8aGYUnGBlhopoCBd94Ev9i
+AZKyMIHbfVYFlAAK7Ci5wuM5GFOLaeI7LQKDzWJY
 ```
 
 # Other Notes
@@ -47,7 +47,7 @@ This encryption scheme replaces the one described in NIP-04, which is not secure
 import {xchacha20} from "@noble/ciphers/chacha"
 import {secp256k1} from "@noble/curves/secp256k1"
 import {sha256} from "@noble/hashes/sha256"
-import {randomBytes, concatBytes} from "@noble/hashes/utils"
+import {randomBytes} from "@noble/hashes/utils"
 import {base64} from "@scure/base"
 
 export const utf8Decoder = new TextDecoder()
@@ -100,44 +100,24 @@ export function encrypt(privkey: string, pubkey: string, text: string, v = 1) {
   const nonce = randomBytes(24)
   const plaintext = utf8Encoder.encode(text)
   const ciphertext = xchacha20(key, nonce, plaintext)
-  const tlv = encodeTLV({
-    0: [new Uint8Array([1])],
-    1: [nonce],
-    2: [ciphertext]
-  })
 
-  return base64.encode(tlv)
+  const payload = new Uint8Array(1 + 24 + ciphertext.length)
+  payload.set([version], 0)
+  payload.set(nonce, 1)
+  payload.set(ciphertext, 1 + 24)
+
+  return base64.encode(payload)
 }
 
 export function decrypt(privkey: string, pubkey: string, payload: string) {
-  let byteArray
-  try {
-    byteArray = base64.decode(payload)
-  } catch (e) {
-    throw new Error(`NIP44: failed to base64 decode payload: ${e}`)
+  const payload = base64.decode(blob)
+  if (payload[0] !== 1) {
+    throw new Error('NIP44: unknown encryption version')
   }
 
-  let tlv
-  try {
-    tlv = parseTLV(byteArray)
-  } catch (e) {
-    throw new Error(`NIP44: failed to decode tlv: ${e}`)
-  }
+  const nonce = payload.subarray(1, 25)
+  const ciphertext = payload.subarray(25)
 
-  if (tlv[0]?.[0]?.[0] !== 1) {
-    throw new Error(`NIP44: invalid version: ${tlv[0]?.[0]?.[0]}`)
-  }
-
-  if (tlv[1]?.[0]?.length !== 24) {
-    throw new Error(`NIP44: invalid nonce: ${tlv[1]?.[0]}`)
-  }
-
-  if (!tlv[2]?.[0]) {
-    throw new Error(`NIP44: missing ciphertext`)
-  }
-
-  const nonce = tlv[1][0]
-  const ciphertext = tlv[2][0]
   const key = getSharedSecret(privkey, pubkey)
   const plaintext = xchacha20(key, nonce, ciphertext)