#openssl
###Install
Install the OpenSSL on Debian based systems
sudo apt-get install openssl###Commands
Create a private key
openssl genrsa -out server.key 2048Generate a new private key and certificate signing request
openssl req -out server.csr -new -newkey rsa:2048 -nodes -keyout server.keyGenerate a self-signed certificate
openssl req -x509 -sha256 -nodes -days 365 -newkey rsa:2048 -keyout server.key -out server.crtGenerate a certificate signing request (CSR) for an existing private key
openssl req -out server.csr -key server.key -newGenerate a certificate signing request based on an existing certificate
openssl x509 -x509toreq -in server.crt -out server.csr -signkey server.keyRemove a passphrase from a private key
openssl rsa -in server.pem -out newserver.pemCheck a certificate signing request (CSR)
openssl req -text -noout -verify -in server.csrCheck a private key
openssl rsa -in server.key -checkCheck a certificate
openssl x509 -in server.crt -text -noout
openssl x509 -in server.cer -text -nooutCheck a PKCS#12 file (.pfx or .p12)
openssl pkcs12 -info -in server.p12Verify a private key matches an certificate
openssl x509 -noout -modulus -in server.crt | openssl md5
openssl rsa -noout -modulus -in server.key | openssl md5
openssl req -noout -modulus -in server.csr | openssl md5Display all certificates including intermediates
openssl s_client -connect www.paypal.com:443Convert a DER file (.crt .cer .der) to PEM
openssl x509 -inform der -in server.cer -out server.pemConvert a PEM file to DER
openssl x509 -outform der -in server.pem -out server.derConvert a PKCS#12 file (.pfx .p12) containing a private key and certificates to PEM
openssl pkcs12 -in server.pfx -out server.pem -nodesConvert a PEM certificate file and a private key to PKCS#12 (.pfx .p12)
openssl pkcs12 -export -out server.pfx -inkey server.key -in server.crt -certfile CACert.crt