What is an encryption backdoor?

Talk of backdoors in encrypted services is once again doing the rounds after reports emerged that the U.K. government is seeking to force Apple to open up iCloud's end-to-end encrypted (E2EE) device backup offering. Officials were said to be leaning on Apple to create a "backdoor" in the service that would allow state actors to access data in the clear. The U.K. has had sweeping powers to limit technology firms' use of strong encryption since passing a 2016 update to state surveillance powers. According to reporting by the Washington Post, U.K. officials have used the Investigatory Powers Act (IPA) to…