Dear mbedtls mailing list members!

I hope you recieve my message now, previously I had problems posting to this list. :(

My first question is actually about the PEM format. As far as I'm aware the PEM format either contains the Private key (signalled by the ---- BEGIN PRIVATE KEY ---- header) or a public key (---- BEGIN PUBLIC KEY -----). In my application I have to work on an app that stores key pairs in a special, secure storage solution (Secure Storage of OPTEE if you've heard about it). I decided to export the keys in PEM format, so that reading and handling them is equal to moving a large string buffer around. Using the PEM format, is there a way to store both private and public keys in the same "file"? Does mbedtls allow for such a solution (does such a solution even exist?).

If not, is there a simple way to get the public key from a private key object? Does the mbedtls_pk_context, (that parsed up with a private key) contain the information needed to export the public key into a PEM buffer? As far as I know mbedtls allows for exporting the private key and the public key with the functions mbedtls_write_key_pem and ...write_pubkey_pem (or something along those lines) does that mean I can only export one at a time and there's no way to save the information for both into one PEM buffer?

If there's a way to save both private and public keys into one PEM file, do I have to parse the private key and public key into separate objects then? With parse_key and parse_pubkey? This isn't really a problem just clarifying.

If you can point me to an actually good description of the PEM format and what CAN be stored inside of it, I'd be very grateful! :)

I also have a question regarding the example SSL server program. In it, the server needs a private key and a certificate for obvious reasons. It also loads a certificate and as far as I know, the certificate has to be tied to a known CA for it to be valid.

I would like to test the program with a self generated key pair, do I need to change the Certificate and CAs to a new one as well? To authenticate the new keypair? Does the mbedtls ssl_client1 example program work with self signed certs? Or do I need to take care of the CA validation myself (that would probably beyond the scope of the project I'm working on).

Thank you in advance!

Yours truly, Máté Zombor