I have found that the best way to educate people on the importance of no government backdoors in encryption is to use the example of TSA approved locks.
Everyone knows when they put a TSA lock on their luggage it does almost nothing to improve the security of their luggage. Any serious criminal has a key to TSA locks.
Adding backdoors is like putting a TSA lock on your bank password. It keeps honest people from seeing it but doesn't do much else.
I use TSA-approved locks that have a little red indicator that pops up if the lock is opened with a key. You can reset the indicator only if you know the combination.
So, when I collect my bags, I can tell whether they've been opened since I last saw them.
Decoding the combinations (and thus resetting the indicators) on those is surprisingly easy. They're actually great for locksport beginners, the key lock is really easy to pick and the combination is easy to decode, AND they're cheap!
It's a great way to make simple and tangible all this nebulous talk of "keys" and "backdoors." I like to include this part about how it only takes one mistake to permanently ruin it all:
>The Washington Post inadvertently published a photograph of all seven of the TSA master keys in an article about TSA baggage handling. The photograph was later removed from the original article, but it still appears in some syndicated copies. In August 2015 this gained the attention of news sites. Using the photograph, security researchers and members of the public have been able to reproduce working copies of the master keys using 3D printing techniques.
Everyone knows when they put a TSA lock on their luggage it does almost nothing to improve the security of their luggage. Any serious criminal has a key to TSA locks.
Adding backdoors is like putting a TSA lock on your bank password. It keeps honest people from seeing it but doesn't do much else.