I need to send sensitive information from one piece of hardware to another. I was thinking wifi, but if someone obtains the password, it wouldn't be encrypted. I don't think you can use ssl unless it's a website, but I may be wrong. I don't know if it makes a difference, but it only needs to be one way.
Depending on your available resources you could look into encrypted short burst radio transmissions.
That would definitely be the most secure one-way method.
With smaller means, just use regular internet connection and encrypt your file sharing. If the question were more specific, I could provide a more specific answer.
Web RTC possibilities seem interesting.
Or you could just encrypt the files and then send them with FTP, properly encrypted, it doesn't matter if someone intercepts them.
It would help if you'd be more specific (information type, hardware, connectivity of hardware, OS), though I use this occasionally when sending sensitive files from phone to PC or vice versa:
- Encrypt file on source (I use Symmetric Key Encryption).
- Setup FTP server on source.
- Open file explorer software on your PC (Graphically, "Explorer.exe" on Windows or the likes of "Nemo" on Linux) and type FTP address.
- Copy it from source.
- Decrypt it on the destination.