Enhanced Security Via Digital Rights Management

It is not enough for OTT players to encrypt premium videos; they also need a secure handling system for licences and decryption keys in order to prevent content leakage.

When it comes to the world of over-the-top (OTT) content, the security of video assets is of the utmost significance. This is because there is a significant demand for premium material in the grey market, where individuals want to watch popular TV shows and movies without paying for access to them. It has an impact on the amount of money that industry leaders such as Netflix, Amazon Prime, Disney+, and others generate in revenue because these companies invest a significant amount of money in order to gain exclusive distribution rights for premium content.

OTT players encrypt video streams with multi-DRM services and manage DRM licences from industry heavyweights such as Google’s Widevine, Apple’s FairPlay, and Microsoft’s PlayReady. These majors include Apple Inc. A reliable multi-DRM service will also safeguard video files by adding a  video watermark. This allows the company to more easily identify places of potential leakage and take corrective measures.

The AES-128 encryption standard is used by many players to encrypt video material; nevertheless, the security of the decryption key is a challenge for these players. Even if the encryption standard is of the highest calibre, content leakage and unauthorised usage of video streams may still occur if the decryption key is not properly safeguarded. OTT players have turned to multi-DRM services as a solution to this issue.

Enhanced Security Via Digital Rights Management

The distribution and administration of encryption and decryption keys, in addition to backend licencing servers, are all functionalities of digital rights management, also known as DRM. The Advanced Encryption Standard (AES) is the encryption method that is utilised by commercial DRM systems. It entails encrypting the premium material so that it can only be read with a decryption key that is issued by a third-party digital rights management provider that has been selected by the OTT platform. Because the same key is used for both encryption and decryption, this approach is known as a symmetric key algorithm. The licence server is where the encryption keys are stored for safekeeping.

When encrypting their videos, content owners typically turn to a cryptographic key with 128 bits of AES. The final consumer is going to need to utilise the same key in order to play back the video material. The content can only be accessed by those users who have the key in their possession. The server belonging to the multi-DRM service provider checks to see if the user and the device in question are approved before it sends back a licence response containing a decryption key.

Since digital content needs to be encrypted to prevent it from being misused or any illicit or unauthorised playback, it should be packaged in a format that is compatible with other media, such as MPEG-DASH or HLS. This ensures that the content can be decrypted when it is needed. Both MPEG-DASH and HLS are examples of streaming protocols that are built on top of HTTP. The source files are encoded into various adaptive streaming formats via the cloud encoding system. The files are encrypted using encryption keys received from many DRM vendors by the encoder.

The multi-DRM packager will send a request for an encryption key to the DRM system, such as Google’s  Widevine, in order to encrypt any digital material. When the DRM system has finished providing the encryption key, that key will immediately be linked to the media content ID. There are circumstances in which the encryption keys are generated within the packager itself before being transmitted to the DRM system for the purposes of storage and distribution to the users. After then, the material is encrypted with the encryption key by the packager.

Prior to the client being able to play back the content, it must first be decrypted. The client has access to the decryption key for the specific content ID that was used to encrypt the video thanks to the digital rights management system (DRM). The Content Decryption Module, often known as CDM, is a piece of specialised software that is either an integral part of the user’s device or their web browser. It is responsible for decrypting information. CDM is included in every device that is compatible with Encrypted Media Extensions (EME). It decrypts the video content and makes it accessible for usage by the player after it has done so.

Although it is technically possible for a studio or content producer to use AES protection for their own content on their own, it is possible that they will not be able to plug the hardware-based leakages or stop the insecure transmission of AES keys between devices or between the server and the client device. When it comes to protecting video content with an AES layer, a multi-DRM solution is the option that fills this gap.

Importance of the AES-CTR and the AES-CBC formats

Common Encryption (CENC), a standardised mechanism for providing digital content protection, has been implemented by leading DRM systems. This technology enables digital content to be protected. The use of CENC makes it possible to encrypt a single content file-set only once so that it can be distributed across several devices or platforms, each of which may use a different DRM scheme. Both the cypher block chaining (CBC) and the counter (CTR) modes are supported by the CENC encryption specification.

The most popular algorithm for block encryption is the Advanced Encryption Standard (AES). Block cyphers are a type of protocol that can be used for both encryption and decryption. A single chunk of plaintext can function as a single block, and it can be applied to the generation of ciphertext chunks of the same size. 128 bits is the size of the encryption block that is being used. There are a few techniques that can be used for padding blocks when the plaintext is not enough of a block; by employing the CBC mode, it is possible to fight against an attack that uses padding. It is also possible to employ the AES mode to support a stream of plaintext, similar to how the cypher feedback (CFB), output feedback (OFB), and CTR modes work. AES-CTR and AES-CBC, which are both used for the encryption of digital information, are not always compatible with one another. This is despite the fact that both modes serve the same objective, which is to encrypt content for security and allow decryption with DRM licencing by a player. AES-CBC is the only cypher that is supported by HLS and Apple devices.

During the encryption process, the video file is made unplayable by being jumbled up using an algorithm. This is accomplished with the assistance of a key, which, along with the algorithm, is utilised to encrypt and decrypt the digital stuff. Every video and every asset component, such as audio, standard definition video (SD), and high definition video (HD), uses its own unique key. Therefore, the process of encrypting or decrypting video is considered a symmetric crypto operation.

Using Multiple DRMs to Your Advantage

A DRM solution allows for the streaming of video content in addition to the option to replay in an offline setting. As a cloud-based solution as a service (SaaS) facility, it manages the digital rights management (DRM) packaging of the source content, providing a service to digital content producers as well as OTT players. It often comes pre-integrated with major cloud services, such as AWS Elemental Media Services through its SPEKE API. This is the case in many situations. In light of this, the standard for communication between those who encrypt and package media assets and those who provide DRM keys is brought to light.

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