If your server/device requires a different certificate format other than Base64 encoded X.509, a third party tool such as OpenSSL can be used to convert the certificates into the appropriate format.

PEM file:

# openssl x509 -in CERTIFICATE.pem -text -noout 

DER file:

# openssl x509 -inform der -in CERTIFICATE.der -text -noout

Note: The PEM format is the most common format used for certificates. Extensions used for PEM certificates are cer, crt, and pem. They are Base64 encoded ASCII files. The DER format is the binary form of the certificate. DER formatted certificates do not contain the “BEGIN CERTIFICATE/END CERTIFICATE” statements. DER formatted certificates most often use the '.der' extension.

# openssl x509 -in certificatename.cer -outform PEM -out certificatename.pem

# openssl x509 -outform der -in certificatename.pem -out certificatename.der

# openssl x509 -inform der -in certificatename.der -out certificatename.pem

Note: The PKCS#7 or P7B format is stored in Base64 ASCII format and has a file extension of .p7b or .p7c. A P7B file only contains certificates and chain certificates (Intermediate CAs), not the private key. The most common platforms that support P7B files are Microsoft Windows and Java Tomcat.

# openssl crl2pkcs7 -nocrl -certfile certificatename.pem -out certificatename.p7b -certfile CACert.cer

# openssl pkcs7 -print_certs -in certificatename.p7b -out certificatename.pem

Note: The PKCS#12 or PFX format is a binary format for storing the server certificate, intermediate certificates, and the private key in one encryptable file. PFX files usually have extensions such as .pfx and .p12. PFX files are typically used on Windows machines to import and export certificates and private keys.

# openssl pkcs12 -in certificatename.pfx -out certificatename.pem

Note: This requires 2 commands

• STEP 1: Convert PFX to PEM

# openssl pkcs12 -in certificatename.pfx -nocerts -nodes -out certificatename.pem

• STEP 2: Convert PEM to PKCS8

# openSSL pkcs8 -in certificatename.pem -topk8 -nocrypt -out certificatename.pk8

Note: This requires 2 commands

• STEP 1: Convert P7B to CER

# openssl pkcs7 -print_certs -in certificatename.p7b -out certificatename.cer

• STEP 2: Convert CER and Private Key to PFX

# openssl pkcs12 -export -in certificatename.cer -inkey privateKey.key -out certificatename.pfx -certfile  cacert.cer