What's the difference between PlayReady/Widevine and ClearKey?

Question

Like the title states, what is the difference between PlayReady/Widevine and ClearKey? Is PlayReady/Widevine better than ClearKey?

Answer 1

ClearKey is a free alternative to commercial DRM solutions for MPEG-DASH content (MPEG-CENC compliant), but as it is only an encryption solution it does not offer the same level of protection as PlayReady, Widevine or Fairplay.

[Opinion:] If you need a complete DRM solution then working with a provider who supports an integrated DRM solution for origin and playback (eg BuyDRM or Ooyala) is going to provide more protection

• Widevine: Widevine is a Hollywood grade DRM technology initially developed by Widevine Technologies and acquired by Google in 2010. Widevine is natively supported on a broad range of devices and browsers such as Google Chrome Browser, Android, Chromecast, etc.
• PlayReady: PlayReady was developed by Microsoft and is one of major DRM systems available, with broad device support, sophisticated features, and has been used for very large scale events such as the Olympics in Sochi, Russia.
• Fairplay: Fairplay is designed for Apple HTTP Live Streaming (HLS) supporting playback on devices such as iPhone, iPad, Apple TV and Mac OS X. Fairplay is also used as Content Decryption Module (CDM) of the Safari browser. This enables HTML5 native playback of (non-standard) DRM encrypted Fairplay streams without plugins in that browser.

Answer 2

The main differences between clear key and the 'normal' DRM's (which Offbeatmammal has nicely summarised) are:

• clear key does not encrypt the key itself. It is simply plain text, 'in the clear'
• No special client side content protection is required to play back the content

To explain the first point, most DRM systems are essentially mechanisms to get a key from a key server to the player device, without anyone being able to intercept or read the key. If someone was able to read the key then they could unencrypt the content. To achieve this DRM systems encrypt the key itself before sending it. For clear key, the key is not encrypted like this.

The second point relates to a secure or protected media path through the client device. This means hardware and/or software in the client device or browser which accepts the encrypted content and the encrypted key and then plays back the content directly to the output device without any input or possibility to copy by any other parts of the system or any other software. Again, clear key does not have this.