ncm-decrypt

A simple ESM-only Node.js library for decrypting .ncm music files.

Note: This library is ESM-only and can only be used in Node.js environments. It is not compatible with browsers or CommonJS.

Features

• Decrypts .ncm format used by NetEase Cloud Music
• Extracts metadata such as title, artist, album, and cover art
• Supports multiple output types: Buffer, Blob, Data URL, etc.

Installation

npm install ncm-decrypt

Usage

import fs from "node:fs/promises"
import { decrypt } from "ncm-decrypt"

const buffer = await fs.readFile("./song.ncm")
const result = await decrypt(buffer, "song.ncm")

console.log(result)

API

decrypt(buffer: Buffer | ArrayBuffer, filename: string): Promise<DecryptResult>

Decrypts a .ncm file and returns a DecryptResult object.

Parameters

• buffer: The file contents as a Buffer or ArrayBuffer
• filename: The original file name (used to infer file extension if needed)

Returns

A Promise that resolves to a DecryptResult object.

DecryptResult Interface

export interface DecryptResult {
  title: string
  album?: string
  artist?: string

  mime: string
  ext: string

  file: string
  blob: Blob | ArrayBuffer
  picture?: string

  message?: string
  rawExt?: string
  rawFilename?: string

  buffer?: ArrayBuffer
  src?: string
}

Example Output

{
  "title": "Sample Song",
  "artist": "Sample Artist",
  "album": "Sample Album",
  "mime": "audio/mpeg",
  "ext": "mp3",
  "file": "Sample Song.mp3",
  "blob": {},
  "picture": "data:image/jpeg;base64,...",
  "message": "Successfully decrypted",
  "buffer": {},
  "src": "data:audio/mpeg;base64,..."
}

License

MIT