Important Openssl Commands : How to

• How to find OpenSSL version

openssl version -a

• How to Create new Private Key and Certificate Signing Request

openssl req -out javaperformance.csr -newkey rsa:2048 -nodes -keyout cgibell.key

• How to create a Self-Signed Certificate

openssl req -x509 -sha256 -nodes -newkey rsa:2048 -keyout javaperformanceselfsigned.key -out javaperformancecert.pem

• How to verify CSR file

openssl req -noout -text -in javaperformance.csr

• How to create RSA Private Key

openssl genrsa -out private.key 2048

• How to remove Passphrase(password) from Key

openssl rsa -in javaperformance.key -out nopassphrase.key

• How to verify Private Key

openssl rsa -in certkey.key –check

• How to verify the Certificate Signer Authority

openssl x509 -in certfile.pem -noout -issuer -issuer_hash

• How to Check Hash Value of A Certificate

openssl x509 -noout -hash -in javaperformance.pem

• How to Convert DER to PEM format

openssl x509 –inform der –in sslcert.der –out sslcert.pem

• How to Convert PEM to DER format

openssl x509 –outform der –in sslcert.pem –out sslcert.der

• How to Convert Certificate and Private Key to PKCS#12 format

openssl pkcs12 –export –out sslcert.pfx –inkey key.pem –in sslcert.pem

• How to Create CSR using an existing private key

openssl req –out certificate.csr –key existing.key –new

• How to Check contents of PKCS12 format cert  – PKCS12 is binary format so you won’t be able to view the content in notepad or another editor.

openssl pkcs12 –info –nodes –in cert.p12

• How to Convert PKCS12 format to PEM certificate

openssl pkcs12 –in cert.p12 –out cert.pem

• How to Test SSL certificate of particular URL

openssl s_client -connect javaperformance.co.in:443 –showcerts

• How to check PEM File Certificate Expiration Date

openssl x509 -noout -in certificate.pem -dates

• How to check Certificate Expiration Date of SSL URL

openssl s_client -connect javaperformance.co.in:443 2>/dev/null | openssl x509 -noout –enddate

Eg:

openssl s_client -connect google.com:443 2>/dev/null | openssl x509 -noout –enddate