Try this:
Download this file:
https://s3.amazonaws.com/bitcoinarmory-releases/armory_0.92.3_sha256sum.txt.asc(it is the signed hash file from here:
https://bitcoinarmory.com/download/ )
And also download Armory for MacOSX from that page too.
and run the following:
gpg --verify armory_0.92.3_sha256sum.txt.asc
If you get the message GOOD signature, then run
sha256sum armory_0.92.3_osx.tar.gz
And you should see something like this:
25aac165bcdfc326ca36e630e9676dd1b116b246209e7bc9b646001977deb947 armory_0.92.3_osx.tar.gz
Then open the file armory_0.92.3_sha256sum.txt.asc in a text editor and check that the line above is in it and matches exactly.