Clave privada:

openssl pkcs12 -nocerts -in certificado.pfx -out privada.key

Enter Import Password:
MAC verified OK
Enter PEM pass phrase:
Verifying - Enter PEM pass phrase:

Clave pública:

openssl pkcs12 -clcerts -nokeys -in certificado.pfx -out publica.cer

Enter Import Password:
MAC verified OK