SSL file formats

SSL certificates come in several file formats, each serving different use cases. Here are the most common ones:

1. PEM (.pem, .crt, .cer, .key)

• Base64-encoded format commonly used in Apache and other web servers.
• Can store certificates, private keys, and intermediate certificates in a text format.

2. DER (.der, .cer)

• Binary format primarily used in Windows and Java environments.
• Contains only the certificate and does not support private keys.

3. PFX/P12 (.pfx, .p12)

• Binary format that includes the private key along with the certificate and intermediate certificates.
• Commonly used in Windows and for importing certificates into software like IIS.

4. CSR (.csr)

• Certificate Signing Request file used to request an SSL certificate from a Certificate Authority (CA).
• Contains the public key and identifying details but not the private key.

Each format serves a different purpose depending on the server and application requirements.