Enlarge Image Tyler Lizenby/CNET

Amazon's Alexa already lets users lock compatible smart locks with a voice command. Voice unlocking, however, is a trickier sell -- after all, no one wants a thief to whisper an unlock command through a cracked window in order to get in, and no lock manufacturer wants to create the appearance of a vulnerability, either.

That's why, up until now, Amazon hasn't included voice unlocking as a feature of Alexa's smart lock software -- but that's changing today. Starting now, compatible smart locks can offer voice unlocking through that native Alexa software, which means that they don't need to craft a custom skill of their own in order to do it, like August did last year. At least one manufacturer, Schlage, plans to take advantage immediately, with voice unlocking available today for its Schlage Sense and Schlage Connect deadbolts.

The feature is turned off by default, so you'll need to log into the Alexa app on your Android or iOS device and select the "unlock by voice" setting to turn it on. Once you do, the app will ask you to pick a four-digit PIN code, which Alexa will ask you for every time you ask her to open up.

Saying a secret PIN code out loud obviously isn't a perfect solution, but it's still a good call. Even better would be to tie voice unlocking in with Alexa's voice-recognition feature, letting you skip the code if Alexa's certain that it's you or a trusted family member speaking. No word yet on whether or not that's in the works, but Amazon says it'll get back to us.

If it is, I'd want to see some improvements to Alexa's voice-recognition software first, since we've already learned that a determined imitator can fool it. One potential protection on that front: The feature will disable itself automatically after three failed voice attempts.

Voice unlocking is rolling out now across all Alexa devices. Alexa-compatible smart locks include the aforementioned August and Schlage deadbolts, as well as locks from Kwikset and Yale.