Obligatory disclosure I have no relation to the Everykey company and do not mean to promote them in any way.
I came across the product Everykey that claims to be "your only key" by allowing you to unlock all your access-controlled devices when you're nearby including car/house door, phone, even logging you into websites. While this sounds cool it also instantly raises many red flags for security.
Their website does a good job of addressing this by explaining they use AES 128-bit encryption to prevent password cracking and eavesdropping
Everykey utilizes AES 128-bit encryption, the same encryption that's used by the military to protect documents with confidential and secret security levels.
it uses a pseudorandom algorithm when sending signals to prevent replay attacks and spoofing
Each time Everykey broadcasts an encrypted Bluetooth 4.0 message, it is different from the previous message, preventing a hacker from sniffing a message and re-broadcasting it.
and the passwords are only stored on the devices themselves and only the device can decrypt the received signal.
Your Everykey broadcasts encrypted information to identify itself, which only your devices are able to decrypt
But how safe is this really? It seems to sound like a garage door opener with better encryption, is that good enough to prevent attacks? Aside from the obvious issue of if you lose the physical device whoever finds it has access to everything.