USEFULL OPENSLL COMMANDS
- SSL - Secure Socket Layer
- CSR - Certificate Signing Request
- TLS - Transport Layer Security
- PEM - Privacy Enhanced Mail
- DER - Distinguished Encoding Rules
- SHA - Secure Hash Algorithm
- PKCS - Public-Key Cryptography Standards
Create new Private Key and Certificate Signing Request
openssl req -out domain.csr -newkey rsa:2048 -nodes -keyout domain.key
Create a Self-Signed Certificate
openssl req -x509 -sha256 -nodes -newkey rsa:2048 -keyout selfsigned.key -out cert.pem
openssl req -x509 -sha256 -nodes -days 360 -newkey rsa:2048 -keyout selfsigned.key -out cert.pem
Verify CSR file
openssl req -noout -text -in domain.csr
Create RSA Private Key
openssl genrsa -out private.key 2048
Remove Passphrase from Key
openssl rsa -in certkey.key -out nopassphrase.key
Verify Private Key
openssl rsa -in certkey.key -check
Verify Certificate File
openssl x509 -in certfile.pem -text -noout
Verify the Certificate Signer Authority
openssl x509 -in certfile.pem -noout -issuer -issuer_hash
Check Hash Value of A Certificate
openssl x509 -noout -hash -in domain.pem
Convert DER to PEM format
openssl x509 -inform der -in sslcert.der -out sslcert.pem
Convert PEM to DER format
openssl x509 -outform der -in sslcert.pem -out sslcert.der
Convert Certificate and Private Key to PKCS#12 format
openssl pkcs12 -export -out sslcert.pfx -inkey key.pem -in sslcert.pem
Convert Certificate and Private Key to PKCS#12 format with chain
openssl pkcs12 -export -out sslcert.pfx -inkey key.pem -in sslcert.pem -chain cacert.pem
Create CSR using an existing private key
openssl req -out certificate.csr -key existing.key -new
Check contents of PKCS12 format cert
openssl pkcs12 -info -nodes -in cert.p12
Convert PKCS12 format to PEM certificate
openssl pkcs12 -in cert.p12 -out cert.pem
Test SSL certificate of particular URL
openssl s_client -connect yoururl.com:443 -showcerts
Find out OpenSSL version
Check PEM File Certificate Expiration Date
openssl x509 -noout -in certificate.pem -dates
Check Certificate Expiration Date of SSL URL
openssl s_client -connect targeturl.com:443 2>/dev/null | openssl x509 -noout -enddate
Check if SSL V2 or V3 is accepted on URL
openssl s_client -connect targeturl.com:443 -ssl2
openssl s_client -connect targeturl.com:443 -ssl3
openssl s_client -connect targeturl.com:443 -tls1
openssl s_client -connect targeturl.com:443 -tls1_1
openssl s_client -connect targeturl.com:443 -tls1_2
Verify if the particular cipher is accepted on URL
openssl s_client -cipher 'ECDHE-ECDSA-AES256-SHA' -connect targeturl:443