Table of Contents

OpenSSL Commands

The most tasks can be done using the gen-webserver-key.pl perl script. This creates all wannted files to request a certificate or to create a self signed certificate.

The usage is very simple:

Just execute perl gen-webserver-key.pl --help:

gen-webserver-key.pl     --host|-h <short host name> [ --privat|-p ] [ --bits|-k <bits for the key (512, 1024, 2048, 4096)> ]
            [ --sha|-s <SHA value> ] [ --java|-j ] [ --interactive|-i ] [ --verbose|-v ] [ --preview ] [ --email|-e ]

or
    
    gen-webserver-key.pl --useold|-o  <host name> [ -p ]
    gen-webserver-key.pl --viewcsr    <host name>
    gen-webserver-key.pl --viewkey    <host name>
    gen-webserver-key.pl --viewcrt    <host name>
    gen-webserver-key.pl --privat     <host name> [ --java ]
    gen-webserver-key.pl --cisco      <host name> [ --rootca <root certificate> ] [ --interca <intermediate certificate> ]
    gen-webserver-key.pl --ldap       <host name> [ --privat ]
    gen-webserver-key.pl --cacert     <host name>
    gen-webserver-key.pl --pemca      <host name>
    gen-webserver-key.pl --domain|-d  <new domain name>
    gen-webserver-key.pl --combine    <host name>
    gen-webserver-key.pl --convert|-c <cer/crt binary certificate file>
--viewcrt            => Just view the content of signed certificate
--viewkey            => Just view the content of ssl key file
--viewcrs            => Just view the content of the unsigned server certificate
--useold             => Generate a privat cert or official cert request using the old key
--privat <host name> => just creates a privat certification from existing privat key, if -p option given, the cert is privat!
--domain <domain>    => overwrites the example.com default
--java               => generates the PKCS12 encoded file for java keystores
--interactive        => enables interactive mode, password and all certificate request data must be entered
--cisco              => Generate the CISCO specific PKCS12 file, you must first generate the certificate request
--ldap               => Creates the need certs for ldap server setup (in PEM format)
--cacert             => Creates the cacert after cert request (needed, if not a privat certificat was requested for PEM, ldap)
--pemca              => Creates the pem CA certificate file for openssl connections (opensll s_client ...), only for private certs!
--combine            => Just combines the crt (PEM) and the key file to one chain.pem file.
-k                   => Default is '2048'
--sha                => SHA encryption algorithm, default is (sha1), possible values [sha sha1 sha224 sha256 sha384 sha512].

Note:   Password for all certs is 'password'
Note: For F5 certificates, standard key and crt (PEM) are OK, the password is 'password' to load it in F5

Important note: Beginning from 2016 the certificate requests must be encrypted with sha256 algorithm, see the --sha option in script!

Certificat generation

 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

openssl req -x509 -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

If you need to check the information within a Certificate, CSR or Private Key, use these commands. You can also check CSRs and check certificates using our online tools.

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 start and end dates

openssl s_client -host <hostname or IP> -port <portnumber> 2>/dev/null| openssl x509 -noout -dates

Debugging using OpenSSL

If you are receiving an error that the private doesn't match the certificate or that a certificate that you installed to a site is not trusted, try one of these commands. If you are trying to verify that an SSL certificate is installed correctly, be sure to check out the SSL Checker.

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

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