What does a PFX container consist of? What is minimally needed to assemble it?

A PFX (Personal Information Exchange) container is a file that contains the private key, the corresponding public key, and a chain of certificates (user certificate and intermediate certificates up to the root).

To assemble a PFX, the minimum required are:

• Private key
• Certificate (public key certificate)

It is also common to include the chain of certificates (intermediate CA) to ensure trust during import.

Example of creating a PFX using OpenSSL:

openssl pkcs12 -export -out cert.pfx -inkey private.key -in cert.crt -certfile chain.crt

Here, private.key is the private key, cert.crt is the certificate, and chain.crt is the chain of intermediate certificates.