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README.md

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+<h1 align="center">gowidevine</h1>
+
+<p align="center">
+🐭 Go implementation of Google's Widevine DRM CDM (Content Decryption Module)
+</p>
+
+<p align="center">
+<img src="https://img.shields.io/github/go-mod/go-version/iyear/gowidevine?style=flat-square" alt="">
+<img src="https://img.shields.io/github/license/iyear/gowidevine?style=flat-square" alt="">
+<img src="https://img.shields.io/github/actions/workflow/status/iyear/widevine/master.yml?branch=master&amp;style=flat-square" alt="">
+<img src="https://img.shields.io/github/v/release/iyear/widevine?color=red&amp;style=flat-square" alt="">
+</p>
+
+## Features
+
+- [x] Implementation of Widevine CDM/Device/Protobuf
+- [x] Decrypt MP4 with Widevine key
+- [x] Covered by realistic data tests
+- [x] Few third-party dependencies
+- [ ] License proxy server/client
+
+## Getting Started
+
+### Install
+
+You first need [Go](https://go.dev/) installed (version 1.18+ is required), then you can use the below Go command to install gowidevine:
+```shell
+go get -u github.com/iyear/gowidevine
+```
+
+### Import
+
+Import the package into your project:
+```go
+import "github.com/iyear/gowidevine"
+```
+
+### Usage
+
+```go
+package main
+
+import (
+	"bytes"
+	"fmt"
+	"io"
+	"net/http"
+
+	widevine "github.com/iyear/gowidevine"
+	"github.com/iyear/gowidevine/widevinepb"
+)
+
+var (
+	clientID   = []byte("foo")
+	privateKey = []byte("bar")
+	psshData   = []byte("baz")
+)
+
+func main() {
+	keys, err := getKeys()
+	if err != nil {
+		panic(err)
+	}
+	if len(keys) == 0 {
+		panic("no keys")
+	}
+
+	for _, key := range keys {
+		fmt.Printf("type: %s, id: %x, key: %x\n", key.Type, key.ID, key.Key)
+	}
+
+	err = widevine.DecryptMP4(bytes.NewBufferString("encrypted data"),
+		keys[0].Key, io.Discard)
+	if err != nil {
+		panic(err)
+	}
+}
+
+func getKeys() ([]*widevine.Key, error) {
+	// Create device from raw data or from wvd file
+	device, err := widevine.NewDevice(
+		widevine.FromRaw(clientID, privateKey),
+		// widevine.FromWVD(bytes.NewReader([]byte("baz"))),
+	)
+	if err != nil {
+		return nil, fmt.Errorf("create device: %w", err)
+	}
+	// Create CDM
+	cdm := widevine.NewCDM(device)
+
+	// Parse PSSH
+	pssh, err := widevine.NewPSSH(psshData)
+	if err != nil {
+		return nil, fmt.Errorf("parse pssh: %w", err)
+	}
+
+	// Get license challenge
+	challenge, parseLicense, err := cdm.GetLicenseChallenge(pssh, widevinepb.LicenseType_AUTOMATIC, false)
+	if err != nil {
+		return nil, fmt.Errorf("get license challenge: %w", err)
+	}
+
+	// Send challenge to license server
+	resp, err := http.DefaultClient.Do(&http.Request{Body: io.NopCloser(bytes.NewReader(challenge))})
+	if err != nil {
+		return nil, fmt.Errorf("request license: %w", err)
+	}
+	defer func() { _ = resp.Body.Close() }()
+
+	license, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return nil, fmt.Errorf("read resp: %w", err)
+	}
+
+	// Parse license
+	keys, err := parseLicense(license)
+	if err != nil {
+		return nil, fmt.Errorf("parse license: %w", err)
+	}
+
+	return keys, nil
+}
+```
+
+## Disclaimer
+
+- The project does not provide Google-provisioned private key and client id except for test purpose.
+- The project does not condone piracy or any action against the terms of the DRM systems.
+- The project is for study and research only, please do not use it for commercial purposes.
+
+## License
+
+GPLv3 License