HDCP and Potential Compatibility Issues

HDCP licensing protects high-value movies, TV shows, and audio

Cable TV concept

John Lamb/Getty Images

High-bandwidth Digital Content Protection is a security feature developed by Intel Corporation that requires the use of HDCP-certified products to receive an HDCP-encrypted digital signal.

It works by encrypting a digital signal with a key that requires authentication from both the transmitting and receiving products. If authentication fails, the signal fails.

Purpose of HDCP

The Digital Content Protection LLC, the Intel subsidiary organization that licenses HDCP, describes its purpose as to license technologies to protect high-value digital movies, TV shows, and audio from unauthorized access or copying. The use of HDCP-compliant cables and devices to transmit HDCP-encoded data, in theory, is designed to prohibit the duplication or re-recording of encrypted media by unauthorized devices.

Put differently: Years ago, people purchased two video cassette recorders, then chained them in series. You'd play a VHS tape (rented, perhaps, from Blockbuster Video), but the signal from that VCR fed a second VCR with a blank tape set to record. That second VCR then fed the TV, so you could watch and copy movies simultaneously without difficulty or detection. The use of HDCP devices and cables now precludes this behavior unless you take extraordinary steps to acquire or modify devices to strip the HDCP encoding from a stream.

The most current HDCP version is 2.3, which was released in February 2018. Most products on the market have a previous HDCP version, which is fine because HDCP is compatible across versions.

Digital Content With HDCP

Sony Pictures Entertainment Inc., The Walt Disney Company, and Warner Bros. were early adopters of HDCP encryption technology.

It is difficult to pinpoint which content has HDCP protection, but it certainly could be encrypted in any form of Blu-ray disc, DVD rental, cable or satellite service, or pay-per-view programming.

The DCP has licensed hundreds of manufacturers as adopters of HDCP.

Connecting HDCP

HDCP is relevant when you use a digital HDMI or DVI cable. If every product using these cables supports HDCP, then you shouldn't encounter any problems. HDCP is designed to prevent theft of digital content, which is another way of saying illicit recording. As a result, the HDCP standard limits how many components you can connect. Most people won't mind, but some applications (for example, feeding a bank of TVs at a sports bar) present difficulties.

If all the products used are HDCP-certified, the consumer won’t notice anything. The problem occurs when one of the products isn’t HDCP-certified. A key aspect of HDCP is that it isn't required by law to be compatible with every interface. It’s a voluntary licensing relationship between the DCP and various companies.

Still, it’s an unanticipated shock to the consumer who connects a Blu-ray disc player to an HDTV with an HDMI cable only to see no signal. The solution to this situation is to either use component cables instead of HDMI or to replace the TV. That’s not the agreement most consumers thought they agreed to when they bought an HDTV that is not HDCP licensed.

HDCP Products

Products with HDCP are sorted into three buckets—sources, sinks, and repeaters:

  • Sources are products where the HDCP signal originates. They are the A point in an A-to-B-to-C order of events. Products in this category include DVRs, set-top boxes, digital tuners, Blu-ray players, and DVD recorders.
  • Sinks are products that receive the HDCP signal and display it somewhere. They are the C point in an A-to-B-to-C order of events. Products in this category include TVs and digital projectors.
  • Repeaters are products that receive the HDCP signal from a source and send it to the sink. They are the B point in an A-to-B-to-C order of events. Products in this category include repeaters, splitters, switchers, AV receivers, and wireless transmitters.

For the curious consumer who wants to verify whether a product has HDCP, the DCP publishes a list of approved products on its website.