Almost everyone knows about BitTorrent Sync.
It’s a freeware but a proprietary software. Sync supports Windows/Linux/OS X platforms. As for Linux, it supports the following architectures/variants: ARM, PowerPC, i386, x64, i386 (glibc 2.3), x64 (glibc 2.3), PPC QorIQ.
And there is also a package made by the community that fits right for my Synology DS413 (the last one above). It can be easily installed after adding http://packages.synocommunity.com to the repositories list.
There’s already some resources available that share secrets publicly:
And here’s some code to produce “insecure secrets” as described here.
echo -n "Enter a passphrase: "
code=`echo -n "$password" | sha1sum | xxd -r -p | python -c 'import sys, base64; print base64.b32encode(sys.stdin.read())'`
Then, “cats” produces this secret: R27WAH4LQCGDFOGS7NLQYLQPXW5TRCW5