CN111556340B - Safe cross-platform video stream playing method - Google Patents

Abstract

The invention discloses a safe cross-platform video stream playing method, which comprises the following steps: 1. the method comprises the steps that HTTPS connection is established between a client and a DASH server, and the client initiates an MPD index file request; 2. the DASH server packs the original video stream into a DASH video fragment and an MPD index file to complete the encryption of the URL tag attributes of the video fragment and the MPD file; 3. the method comprises the steps that a server receives a request of a client for initiating an MPD index file, and sends an encrypted MPD index file, a decryption key of each DASH video fragment and a server CRC (cyclic redundancy check) value; 4. the client receives a file sent by the server; 5. comparing the CRC value of the server side with the CRC value of the client side; 6. and the client dynamically selects a proper URL to initiate a video fragment request to the DASH server according to the current network condition, analyzes the video fragments according to the decryption key value corresponding to each video fragment, and finishes the playing of the video stream. The method of the invention provides encryption protection for the video stream fragments in the transmission process, and improves the safety in the video transmission process.

Description

A Secure Cross-Platform Video Streaming Method

technical field

The invention belongs to the technical field of Internet streaming media, and in particular relates to a safe cross-platform video streaming playback method.

Background technique

With the development of streaming media technology and HTML5 technology, the HTTP adaptive transport protocol has gradually replaced the traditional real-time streaming protocol (RTP and RTSP). Among them, the widely used adaptive transport protocols mainly include Adobe's HDS, Microsoft The company's MSS and Apple's HLS protocol, but they have their own unique data segmentation format, based on this, MPEG and other organizations such as 3GPP released the DASH (Dynamic Adaptive Streaming over HTTP) protocol international standard.

With the help of the cross-platform nature of the browser and the MSE (Media Source Extension) extension technology provided by the HTML5 standard, the DASH protocol can easily complete the playback of cross-platform adaptive streaming media. The two most important parts are MPD (Media Presentation). Description) index file and video slice, wherein the MPD file is in XML format and describes the frame rate, resolution, URL and other details of the current slice. The client requests the MPD file to the server in real time and completes the parsing, selects the appropriate URL tag in the MPD file according to the current network conditions, and then uses the URL to initiate a video fragmentation request to the server to complete the playback of the video stream. At present, more and more companies choose DASH technology in the selection of video streaming technology, such as YouTube, Google, Facebook, iQiyi, etc.

However, in the common DASH-based video stream transmission system, due to the openness of the HTTP protocol, the entire video segmentation request and transmission process are carried out in plain text; some mobile devices also cache some videos locally in order to improve user experience. Fragments are available for offline viewing, but these are not encrypted, and the complete video can be viewed with simple file merging. Therefore, there is a great security risk in file transmission.

The present application proposes a secure cross-platform video stream playback method, which has important practical application value for preventing the leakage of video segments caused by the theft of MPD files and the destruction of video copyrights.

SUMMARY OF THE INVENTION

The object of the present invention is to provide a safe cross-platform video stream playback method, which completes the cross-platform video playback on the basis of the DASH protocol. Security of the transmission process.

The technical solution adopted in the present invention is a safe cross-platform video stream playback method, which specifically includes the following steps:

Step 1. An HTTPS connection request is established between the client and the server, and the client initiates an MPD index file request;

Step 2, the server DASH server packs and processes the original video stream into several DASH video fragments and MPD index files, and simultaneously encrypts the URL tags of each DASH video fragment and MPD index file to obtain encrypted MPD index files and Each DASH video segment decrypts the key value and stores it, and calculates the server CRC value;

Step 3, the DASH server accepts the MPD index file request initiated by the client, and transmits the encrypted MPD index file, each DASH video fragment decryption key value and the server CRC check value to the client through the RPC interface according to a fixed format;

Step 4, the client receives the encrypted MPD index file transmitted by the DASH server, each DASH video fragment decryption key value and the server CRC check value, and calculates the client CRC check value;

Step 5. The client compares the server CRC check value with the client CRC check value:

If the server CRC check value is the same as the client CRC check value, the client performs further analysis to complete the decryption of the URL tag of the MPD index file, and parses and stores the decryption key value of each DASH video segment at the same time;

If the server CRC check value is different from the client CRC check value, the client discards the encrypted MPD index file, the decryption key value of each DASH video segment and the server CRC check value passed by the DASH server in step 3, and selects Repeat steps 1 to 4 for the new original video stream until the server CRC check value is the same as the client CRC check value, the client performs further analysis, completes the decryption of the URL tag of the MPD index file, and parses and stores each DASH at the same time. Video fragment decryption key value;

Step 6, the client dynamically selects the URL label of the appropriate MPD index file according to the current network conditions, and initiates a video request to the DASH server. After the DASH server accepts the video request, the client decrypts the encrypted data according to each DASH video fragment stored in step 5. The key value decrypts each DASH video segment to complete the playback of the original video stream.

The present invention is also characterized in that,

The specific process of step 1 is as follows:

Step 1.1, start the server DASH server, make it in the listening state, and wait for the client connection request;

Step 1.2. The client logs in, and initiates an MPD index file request to the DASH server program with the token information and timestamp returned after successful login.

In step 2, the process of packaging and processing the original video stream is as follows: the DASH server starts the video processing thread, and the original video stream is packaged and processed into MPEG-DASH format, and several DASH video fragments and MPD index files are generated and stored on the server side.

In step 2, the DASH video fragment adopts AES-128 encryption method to encrypt and store, and the URL label of MPD index file adopts XOR encryption algorithm to encrypt and store;

In step 2, the decryption key value of each DASH video segment is dynamically generated according to the token information, timestamp and device information returned by the client after successful login, ensuring that each video segment has a different decryption algorithm and ensuring the security of the overall video file. .

In step 2, the CRC check value is calculated from two parts of the content written in the MPD index file and the DASH video fragment decryption key value.

The fixed format of file transfer in step 3 is: 2-byte MPD file content length + MPD file content + 2-byte server-side CRC check value length + server-side CRC check value + 4-byte DASH video fragment decryption key Value length + DASH video fragment decryption key value.

In the method of the present invention, depending on the adaptability of the DASH protocol, each fragment may have multiple corresponding URLs, and the client dynamically selects the appropriate URL according to the current network condition, and initiates a video fragmentation request to the server, Decrypt the returned video segments as required to complete the video stream playback.

The beneficial effects of the present invention are as follows: a safe cross-platform video stream playback method of the present invention, combined with the characteristics of the DASH protocol itself, completes the encrypted transmission of video segment files on the basis of video stream cross-platform transmission and playback. The secret key values required for decryption of each fragment are different, which further increases the difficulty of video cracking, improves the security of video stream data transmitted in the DASH system, and plays a good role in promoting the copyright protection of video files.

Description of drawings

Fig. 1 is a flow chart of a method for playing a safe cross-platform video stream according to the present invention.

Detailed ways

The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

A safe cross-platform video stream playback method of the present invention, as shown in Figure 1, specifically includes the following steps:

Step 1. Start the DASH server on the server side to make it in a listening state, establish an HTTPS connection request between the client and the server, and the client logs in and initiates MPD indexing to the DASH server program with the token information and timestamp returned after successful login file request;

Step 2. The DASH server starts the video processing thread, packages the original video stream into MPEG-DASH format, generates a number of DASH video segments and MPD index files and stores them on the server, and uses AES-128 encryption method for each DASH respectively. Encrypt the video fragment; use the XOR encryption algorithm to encrypt the URL tag of the MPD index file, obtain the encrypted MPD index file and the decryption key value of each DASH video fragment and store it, and calculate the server CRC value;

The decryption key value of each DASH video fragment is dynamically generated according to the token information, timestamp and device information returned by the client after successful login, to ensure that each video fragment decryption algorithm is different, and to ensure the security of the overall video file.

Step 3, the DASH server accepts the MPD index file request initiated by the client, and transmits the encrypted MPD index file, each DASH video fragment decryption key value and the server CRC check value to the client through the RPC interface in a fixed format;

The fixed format is: 2 bytes MPD file content length + MPD file content + 2 bytes server CRC check value length + server CRC check value + 4 bytes DASH video fragment decryption key value length + DASH video Shard decryption key value.

Step 4, the client receives the encrypted MPD index file transmitted by the DASH server, each DASH video fragment decryption key value and the server CRC check value, and calculates the client CRC check value;

Step 5. The client compares the server CRC check value with the client CRC check value:

If the server CRC check value is the same as the client CRC check value, the client performs further analysis to complete the decryption of the URL tag of the MPD index file, and parses and stores the decryption key value of each DASH video segment at the same time;

If the server CRC check value is different from the client CRC check value, the client discards the encrypted MPD index file, the decryption key value of each DASH video segment and the server CRC check value passed by the DASH server in step 3, and selects Repeat steps 1 to 4 for the new original video stream until the server CRC check value is the same as the client CRC check value, the client performs further analysis, completes the decryption of the URL tag of the MPD index file, and parses and stores each DASH at the same time. Video fragment decryption key value;

Step 6, the client dynamically selects the URL label of the appropriate MPD index file according to the current network conditions, and initiates a video request to the DASH server. After the DASH server accepts the video request, the client decrypts the encrypted data according to each DASH video fragment stored in step 5. The key value decrypts each DASH video segment to complete the playback of the original video stream.

In the method of the present invention, the CRC check value is calculated from two parts of the content written in the MPD index file and the DASH video fragmentation decryption secret key value. The attribute value is encrypted, and the DASH video fragment decryption key corresponding to the URL is written to the end of the MPD index file, and the CRC value of the entire file is calculated.

Depending on the adaptability of the DASH protocol, each DASH video segment may have multiple corresponding URLs. The client dynamically selects the appropriate URL according to the current network conditions, initiates a video segment request to the server, and analyzes the returned video segments. The video is decrypted according to the procedure, and the video stream is played.

The method of the present invention completes the encrypted transmission of the video fragment file on the basis of the cross-platform transmission and playback of the video stream, because the decryption key value of each DASH video fragment is based on the token information and time stamp returned after the client successfully logs in. And the dynamic generation of device information ensures that each video fragment has a different decryption algorithm, which further increases the difficulty of video cracking and improves the security of video stream data transmitted in the DASH system. The leak of the film and the destruction of the copyright of the video have important practical application value.

Claims (3)

1. A safe cross-platform video stream playing method is characterized by comprising the following steps:

step 1, establishing an HTTPS connection request between a client and a server, and initiating an MPD index file request by the client;

the specific process is as follows:

step 1.1, starting a DASH server at a service end to enable the DASH server to be in a monitoring state and waiting for a client connection request;

step 1.2, a client logs in and initiates an MPD index file request to a DASH server with token information and a timestamp returned after successful login;

step 2, the DASH server of the server packs the original video stream into a plurality of DASH video fragments and MPD index files, simultaneously encrypts URL tags of each DASH video fragment and each MPD index file respectively to obtain and store the encrypted MPD index files and decryption key values of each DASH video fragment, and calculates CRC values of the server;

the process of the original video stream packing processing specifically comprises the following steps: starting a video processing thread by a DASH server, packaging and processing an original video stream into an MPEG-DASH format, generating a plurality of DASH video fragments and an MPD index file, and storing the DASH video fragments and the MPD index file in a server;

the DASH video segments are encrypted and stored in an AES-128 encryption mode, and URL tags of MPD index files are encrypted and stored in an exclusive-or encryption algorithm;

step 3, the DASH server receives an MPD index file request initiated by the client, and transmits the encrypted MPD index file, each DASH video fragment decryption key value and the server CRC value to the client through an RPC interface according to a fixed format;

each DASH video fragment decryption key value is dynamically generated according to token information, a timestamp and equipment information returned after a client successfully logs in, so that different video fragment decryption algorithms are guaranteed, and the safety of the whole video file is guaranteed;

step 4, the client receives the encrypted MPD index file, each DASH video fragment decryption key value and the server CRC check value transmitted by the DASH server, and calculates the client CRC check value;

step 5, the client compares the CRC value of the server with the CRC value of the client:

if the CRC value of the server side is the same as the CRC value of the client side, the client side further analyzes to finish decryption of a URL (uniform resource locator) tag of an MPD (MPD media stream index) file, and analyzes and stores a decryption key value of each DASH video fragment;

if the server side CRC check value is different from the client side CRC check value, the client side discards the encrypted MPD index file, each DASH video fragment decryption key value and the server side CRC check value transmitted by the DASH server in the step 3, selects a new original video stream and repeats the steps 1-4 until the server side CRC check value is the same as the client side CRC check value, and the client side further analyzes to complete decryption of the URL label of the MPD index file and simultaneously analyzes and stores each DASH video fragment decryption key value;

and step 6, the client dynamically selects a proper URL tag of the MPD index file according to the current network condition, initiates a video request to the DASH server, and when the DASH server receives the video request, the client decrypts each DASH video fragment according to each DASH video fragment decryption key value stored in the step 5 to finish the playing of the original video stream.

2. The method of claim 1, wherein the CRC check value in step 2 is calculated by writing both contents of MPD index file and decryption secret key value of DASH video segment.

3. The method as claimed in claim 1, wherein the fixed format of file delivery in step 3 is: 2-byte MPD file content length + MPD file content + 2-byte server CRC check value length + server CRC check value + 4-byte DASH video segment decryption key value length + DASH video segment decryption key value.

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