# Common OpenSSL Commands ## General OpenSSL Commands * Generate a new private key and Certificate Signing Request ``` openssl req -out CSR.csr -new -newkey rsa:2048 -nodes -keyout privateKey.key ``` * Generate a self-signed certificate (see How to Create and Install an Apache Self Signed Certificate for more info) ``` openssl req -x509 -sha256 -nodes -days 365 -newkey rsa:2048 -keyout privateKey.key -out certificate.crt ``` * Generate a certificate signing request (CSR) for an existing private key ``` openssl req -out CSR.csr -key privateKey.key -new ``` * Generate a certificate signing request based on an existing certificate ``` openssl x509 -x509toreq -in certificate.crt -out CSR.csr -signkey privateKey.key ``` * Remove a passphrase from a private key ``` openssl rsa -in privateKey.pem -out newPrivateKey.pem ``` ## Checking Using OpenSSL * Check a Certificate Signing Request (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 ``` * List the certificates stored in a PKCS12 keystore with Java Keytool ``` keytool -list -v -keystore -storepass -storetype PKCS12 ``` ## Debugging Using OpenSSL * Check an MD5 hash of the public key to ensure that it matches with what is in a CSR or private key ``` openssl x509 -noout -modulus -in certificate.crt | openssl md5 openssl rsa -noout -modulus -in privateKey.key | openssl md5 openssl req -noout -modulus -in CSR.csr | openssl md5 ``` * Check an SSL connection. All the certificates (including Intermediates) should be displayed ``` openssl s_client -connect www.paypal.com:443 ``` ## Converting Using OpenSSL * 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) containing a private key and certificates to PEM ``` openssl pkcs12 -in keyStore.pfx -out keyStore.pem -nodes ``` * 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 ``` ## Reference *