what is a csr file

In public key infrastructure (PKI) systems, a certificate signing request (also CSR or certification request) is a message sent from an applicant to a certificate authority in order to apply for adigital identity certificate. The most common format for CSRs is the PKCS#10 specification and another is the Signed Public Key and Challenge Spkac format generated by some web browsers.

You may display the information contained in csr

openssl req -text -in request.csr

Actually PKCS #12 is the successor to Microsoft's "PFX".^[6] But confusingly the terms "PKCS #12 file" and "PFX file" are sometimes used interchangeably.^{[4] [5] [7]}

Microsoft's "PFX" has received heavy criticism of being one of the most complex cryptographic protocols.^[7]

Many different file types are produced and consumed when creating an SSL certificate.

• A .csr file is a certificate signing request which initiates your certificate request with a certificate provider and contains administrative information about your organization.
• A .key file is the private key used for your site’s SSL-enabled requests.
• .pem and .crt extensions are often used interchangeably and are both base64 ASCII encoded files. The technical difference is that .pem files contain both the certificate and key whereas a .crt file only contains the certificate. In reality this distinction is often ignored.
• .cer - certificate stored in the X.509 standard format. This certificate contains information about the certificate's owner... along with public and private keys.
  .pvk - files are used to store private keys for code signing. You can also create a certificate based on .pvk private key file.
  .pfx - stands for personal exchange format. It is used to exchange public and private objects in a single file. A pfx file can be created from .cer file. Can also be used to create a Software Publisher Certificate.
  
  

Export private key pem from p12

openssl pkcs12 -nocerts -out private_key.pem -in abc.p12
Export public key pem from p12

openssl pkcs12 -in abc.p12 -out myPublicKey.pem -clcerts -nokeys