openssl req -out CSR.csr -pubkey -new -keyout privateKey.key -config .shareopenssl.cmf

Generate a CSR for an existing private key

openssl req -out CSR.csr -key privateKey.key -new

Generate a CSR based on an existing certificate

openssl x509 -x509toreq -in MYCRT.crt -out CSR.csr -signkey privateKey.key

Generate a self-signed certificate

openssl req -x509 -nodes -days 365 -newkey rsa:2048 -keyout privateKey.key -out certificate.crt

Remove a password from a private key

openssl rsa -in privateKey.pem -out newPrivateKey.pem

Check the CSR, Private Key or Certificate using OpenSSL

Check a CSR

openssl req -text -noout -verify -in CSR.csr

Check a private key

openssl rsa -in privateKey.key -check

Check a certificate

openssl x509 -in certificate.crt -text -noout

Check a PKCS#12 file (.pfx or .p12)

openssl pkcs12 -info -in keyStore.p12

Check the MD5 hash of the public key to check if it is equal to what is in the CSR or private key

openssl x509 -noout -modulus -in certificate.crt | openssl md5openssl rsa -noout -modulus -in privateKey.key | openssl md5openssl req -noout -modulus -in CSR.csr | openssl md5

Check an SSL connection. All certificates (also intermediate certificates) should be displayed

openssl s_client -connect www.nguyenanhdung.info:443

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 PKCS#12 file (.pfx .p12) including the private key and certificate(s) to PEM

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

Note: Add -nocerts to only convert the private key, or add -nokeys to convert only the certificates.

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 ssh private key to pem

openssl rsa -in ~/.ssh/id_rsa -outform pem > id_rsa.pem