Very nice Emin! This could be very useful as a building block for oracle based services. If only there were opcodes for working with X.509 ;)

I'd suggest at least documenting in the FAQ how to extract the data from the certificate:

openssl pkcs12 -in virtual-notary-cert-stocks-16070.p12 -nodes -passin pass:"" | openssl x509 -text|less

That's good enough to get started, but I note two issues:

  1. X.509 is kind of annoying to work with: example code in popular languages/frameworks to extract the statement would be useful.

  2. The stock price plugin, at least, embeds the data as text inside the X.509 certificate. That's also not terribly developer friendly and risks parsing errors undermining security schemes built on it.

    The way I'd solve this is to embed either a protocol buffer or DER encoded structure inside the extension, so developers can extract the notarised data directly, without needing to do any additional parsing.