Convert certificates with OpenSSL

Convert a DER file (.crt .cer .der) to PEM

openssl x509 -inform der -in certificate.cer -out certificate.pem

Convert a PEM file to DER

openssl x509 -outform der -in certificate.pem -out certificate.der

Convert a PEM file to P7B

openssl crl2pkcs7 -nocrl -certfile certificate.cer -out certificate.p7b -certfile CACert.cer

Convert a PEM certificate file and a private key to PKCS#12 (.pfx .p12)

openssl pkcs12 -export -out certificate.pfx -inkey privateKey.key -in certificate.crt -certfile CACert.crt

Convert a PKCS#12 file (.pfx .p12) containing a private key and certificates to PEM

openssl pkcs12 -in keyStore.pfx -out keyStore.pem -nodes

You can add -nocerts to only output the private key or add -nokeys to only output the certificates.

Convert a P7B to PEM

openssl pkcs7 -print_certs -in certificate.p7b -out certificate.cer

Convert a P7B to PFX

openssl pkcs7 -print_certs -in certificate.p7b -out certificate.cer
openssl pkcs12 -export -in certificate.cer -inkey privateKey.key -out certificate.pfx -certfile CACert.cer

Export public key from private key

openssl rsa -in privkey.pem -pubout > key.pub

Remove password from private key

openssl rsa -in [file1.key] -out [file2.key]