Access key pairs in a macOS keychain from the commandline

Question

I created a key pair in like this:

security create-keypair -a dsa -s 4096 FooBar

Now I want to access this key from to the command line to actually use it (in .pem format if possible). However, security doesn't have a find-keypairoption, and I couldn't get any of the other find_... subcommands to work. Is there a way to do this?

Edit:

For now I found an (inconvenient) workaround:

1. First, manually create a "secure note" in keychain access, whose contents is the the private key.
2. Use the following abomination: security find-generic-password -w -s "$SecureNoteName" | xxd -p -r | plutil -extract "NOTE" xml1 -o - - | xmllint --xpath '//string/text()' -

So it seems I first have to fight the keychain to get its contents, and then I have to fight the plist to get the value... Parsing the plist could be simplified with the defaults command, but I wanted to avoid writing the key to a temp file, and I couldn't get defaults to read from stdin.