Tips and Tricks for dealing with SSL

### 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`

## Inspecting ### 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` ### 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`

### Remove a passphrase from a private key `openssl rsa -in privateKey.pem -out newPrivateKey.pem` --- ## Mutating and transforming certificates and keys Using OpenSSL These commands allow you to convert certificates and keys to different formats to make them compatible with specific types of servers or software. For example, you can convert a normal PEM file that would work with Apache to a PFX (PKCS#12) file and use it with Tomcat or IIS. Use our SSL Converter to convert certificates without messing with 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` You can add `-nocerts` to only output the private key or add `-nokeys` to only output the certificates. ### 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`