Microsoft CryptoAPI: how to convert PUBLICKEYBLOB to DER/PEM?

Question

I have a generated RSA key pair stored as PRIVATEKEYBLOB and PUBLICKEYBLOB, and I need to be able to convert these keys to DER or PEM formats so I could use it in PHP or Python.

Answer 1

Use RSA_CSP_PUBLICKEYBLOB as documented in https://msdn.microsoft.com/en-us/library/windows/desktop/aa378145(v=vs.85).aspx