In the latest Golang release (1.5.3), the documentation for x509.ParsePKIXPublicKey() says the function takes in a []byte of DER encoded public key and returns pub interface{}. It is not obvious exactly what pub is or how to use it unless digging inside the source code and trace to the function parsePublicKey().

Suggested changes:

• Mention explicitly what kind of public key input we support (RSA, DSA, ECDSA)
• Mention the type of pub in those three cases respectively
• Add a short example on how to use switch statement along with type assertions to obtain the correct type of public key.

I will be happy to make those improvements to the document and submit for code review if no objections from the project maintainers.