Useful openssl Command Examples -

Check version of openssl:

# openssl version

Print available commands for openssl:

# openssl list -standard-commands

	or				

# openssl help

Check SSL certificate of mentioned URL:

# openssl s_client -connect varelite.com:443 -showcerts

To generate rsa key:

# openssl genrsa -out testing.key 2048

Generate CSR and RSA key:

# openssl req -out testing.csr -newkey rsa:2048 -nodes -keyout testing.key

Generate a self signed certificate:

# openssl req -x509 -sha256 -nodes -newkey rsa:2048 -keyout testing1.key -out testing1.pem

Check CSR file:

# openssl req -noout -text -in testing.csr

Check RSA key: (It will prompted for pass phrase if exists)

# openssl rsa -in testing.key -check

Verify Certificate:

# openssl x509 -in testing1.pem -text -noout

Check hash value of a certificate:

# openssl x509 -noout -hash -in testing1.pem

Print CSA (Certificate Signer Authority) of certificate:

# openssl x509 -in testing1.pem -text -noout -issuer -issuer_hash

Print public key:

# openssl rsa -in testing.key -pubout

Print Modulus and public key:

# openssl rsa -in testing.key -pubout -modulus

Print RSA key in textual format:

# openssl rsa -in testing.key -text -noout

Print session information when the program exits:

# openssl s_client -connect varelite.com:443 -prexit