Common OpenSSL Commands with Keys and Certificates

openssl.md

Common OpenSSL Commands with Keys and Certificates

Generate RSA private key (2048 bit)

openssl genrsa -out private.pem 2048

Generate a Certificate Signing Request (CSR)

openssl req -sha256 -new -key private.pem -out csr.pem

Generate RSA private key (2048 bit) and a Certificate Signing Request (CSR) with a single command

openssl req -new -newkey rsa:2048 -nodes -keyout server.key -out server.csr

Convert private key to PEM format

openssl rsa -in server.key -outform PEM -out server.pem

Generate a self-signed certificate that is valid for a year with sha256 hash

openssl x509 -req -sha256 -days 365 -in csr.pem -signkey private.pem -out certificate.pem

View details of a RSA private key

openssl rsa -in private.pem -text -noout

View details of a CSR

openssl req -in csr.pem -text -noout

View details of a Certificate

openssl x509 -in certificate.pem -text -noout

View details of a Certificate in DER format

openssl x509 -inform der -in certificate.cer -text -noout

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.cer

To get a public key for SSH purposes, use ssh-keygen:

ssh-keygen -y -f key.pem > key.pub