wellcomez / ksm

FairPlay Key Security Module written in Go (Golang).

ksm

Apple FairPlay Streaming (FPS) securely delivers keys to Apple mobile devices, Apple TV, and Safari on OS X, which will enable playback of encrypted video content.

This project is FairPlay Streaming Key Security Module written in Go (Golang).

Usage

Start using it

Download and install it:

$ go get github.com/easonlin404/ksm

Verify ckc

Perform verification utility verify_ckc to test KSM implementation.

testdata/verify_ckc -s testdata/FPS/spc1.bin -c testdata/FPS/ckc1.bin

Simple example

See example/basic.go. You have to implement your contentKey and D func if you want to use Apple FairPlay DRM.

package main

import (
	"encoding/base64"
	"fmt"
	"math/rand"
	"net/http"

	"github.com/easonlin404/ksm"
	"github.com/easonlin404/ksm/d"
	"github.com/gin-gonic/gin"
	"github.com/gin-gonic/gin/binding"
)

func main() {

	r := gin.Default()

	type SpcMessage struct {
		Spc     string `json:"spc" binding:"required"`
		AssetId string `json:"assetId"`
	}

	r.POST("/fps/rest/getLicense", func(c *gin.Context) {
		var spcMessage SpcMessage
		if err := c.ShouldBindWith(&spcMessage, binding.JSON); err != nil {
			c.JSON(http.StatusBadRequest, gin.H{
				"err": err.Error(),
			})
			return
		}

		fmt.Printf("%v\n", spcMessage)

		playback, err := base64.StdEncoding.DecodeString(spcMessage.Spc)
		checkError(err)

		k := &ksm.Ksm{
			Pub:       pub,
			Pri:       pri,
			Rck:       RandomContentKey{}, // Use random content key for testing
			DFunction: d.AppleD{},         // Use D function provided by Apple Inc.
			Ask:       []byte{},
		}
		ckc, err2 := k.GenCKC(playback)
		checkError(err2)

		ckcBase64 := base64.StdEncoding.EncodeToString(ckc)
		c.JSON(http.StatusOK, gin.H{
			"ckc": ckcBase64,
		})
	})

	r.Run(":8080")

}

func checkError(err error) {
	if err != nil {
		panic(err)
	}
}

// Random content key
type RandomContentKey struct {
}

// Implement FetchContentKey func
func (RandomContentKey) FetchContentKey(assetId []byte) ([]byte, []byte, error) {
	key := make([]byte, 16)
	iv := make([]byte, 16)
	rand.Read(key)
	rand.Read(iv)
	return key, iv, nil
}

// Implement FetchContentKeyDuration func
func (RandomContentKey) FetchContentKeyDuration(assetId []byte) (*ksm.CkcContentKeyDurationBlock, error) {

	LeaseDuration := rand.Uint32()  // The duration of the lease, if any, in seconds.
	RentalDuration := rand.Uint32() // The duration of the rental, if any, in seconds.

	return ksm.NewCkcContentKeyDurationBlock(LeaseDuration, RentalDuration), nil
}

FAQ

How to send sample SPC data?

Our example/basic.go router has to accepted SPC parameter that is base64 encoding. And testdata/spc1.bin is binary file, so you have to encode to base64 string.

After run as local server, you can test sample POST request using httpie tool(spc is spc1.bin base64 encoding):

http POST http://localhost:8080/fps/rest/getLicense spc=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

Will response:

HTTP/1.1 200 OK
Content-Length: 902
Content-Type: application/json; charset=utf-8
Date: Thu, 08 Mar 2018 05:51:02 GMT

{
    "ckc": "AAAAAQAAAAAqQk6qsqGlLq37TNsWDOnKAAACgKtZF0mIK6FPslvHP3oQdTZgepM5j4nnI/d//Rj+T4eTBfmKA4aVPwUr4bOozAhPvpL9QhXKIsGo9sEmtz0j0okdbnTTWCYAfLTHGwYviWMsR0J/vFtlFnxJF2yyLhDN6wu4/Be8Q7+B2duXsW7k5r6TF/gaKYbgTChM/3b+znqizRy06gNJr4d5HUKfXZ9FAmBtcsTUGbdMWjvKYJV8zPiYoayTkarXN6bDGMY2ToDyWBXIethDf4kBgdpOcR+qvXLntbI9daaEbb2XEU/nw4v6Dks6/sMMizb0rtY3fA4dCxEYeVxlAOLlLGLxswtRkZmNj1YQD/2HUGmuLBo7Q+17MGvRP06d+LG3YaDWbLeRPH5CVCwaxvmj1mFSLvMZffLgPSYZUp9fXaEeUnh8aD/mvaaFJavLmB7+uk+YggX+9F1HtjpFpjelvX5InP2L3mSYOl/eNdjzJbFw7l9BnR5KWL1wWiOmJHEWBw3Y+Tx5bLs/1QMasyTG+wAGxiXN+XyQW8frVO7e1xeBnuJplSEx+DK4Z9ZtveQG2l56OMsyw3KxUPTjCzHF5n1z6CzCSw5R57gA23mQ3nScPkDCbzQyaquZfCO80f6JW9hMGVEIFPnZVtUR1IemNKXK3fx+fZ9GdIN0EaNCp9fzB5GDC2dxrs9zhux3SvR5nKbSqHCX2b0S2S7Vn0LWZ7U4MtXMB2R8rsza03JEswAZ7iGKgl1J5L7TaADKz5cZvBkTR5P6QgHiesoZ9HMxQHtCyU4pjjGlFU081UKmsxefuuddPjwK93M/Xhf4wjOjcSSG5a1+Gg9FTi4tETdnMXVl/PuWjX1WFYCIJ1ZyKc2gZD2iEbw="
}

How to verifying Key Security Module (KSM) Implementation?

https://developer.apple.com/library/archive/technotes/tn2454/_index.html#//apple_ref/doc/uid/DTS40017630-CH1-VERIFYING_KEY_SECURITY_MODULE__KSM__IMPLEMENTATION

How to Debugging FairPlay Streaming?

https://developer.apple.com/library/archive/technotes/tn2454/_index.html