Openssl

https://access.redhat.com/solutions/1519813 Thanks Boris
update-ca-trust enable
cp rapidSSL-ca.crt /etc/pki/ca-trust/source/anchors/
update-ca-trust extract
openssl verify rapidSSL-ca.crt

Check that a certificate matches a private key or certificate request

General OpenSSL Commands

Convert certificates from one type to another
PEM to DER

openssl x509 -in cert.crt -outform der -out cert.der

DER to PEM

openssl x509 -in cert.crt -inform der -outform pem -out cert.pem

View Certificate Revocation List

openssl crl -noout -text -in example.crl ( PEM encoded )

openssl crl -inform DER -noout -text -in example.crl ( DER encoded )

The below commands allow you to generate CSRs, Certificates, Private Keys and do other miscellaneous tasks.
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

Calculating sha-1 fingerprint

openssl x509 -noout -in idp_blabla_ac_uk.crt -fingerprint -sha1

Calculating SHA-256 fingerprint

openssl x509 -noout -fingerprint -sha256 -in filename.crt

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 the fingerprint of a certificate.

Get SHA-1 fingerprint:

openssl x509 -noout -in certificate.pem -fingerprint -sha1

Get SHA-256 fingerprint:

openssl x509 -noout -in certificate.pem -fingerprint -sha256

You can check if an SSL certificate matches a Private Key by using the 2 easy commands below.

For your SSL certificate: openssl x509 -noout -modulus -in <file>.crt | openssl md5

For your RSA private key: openssl rsa -noout -modulus -in <file>.key | openssl md5

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

Diagnosing server certificate problems
When testing, beware that most modern browsers will automatically download intermediate certificates if your server fails to supply them so it can be difficult to tell if you have got things right for any that won't. One way to double-check is to use the 'openssl s_client' command to inspect the certificates being returned by a web server:

openssl s_client -connect <server>:<port> -showcerts

Replacing <server> and <port> appropriately (<port> probably needs to be 443). This actually establishes a connection to the server - you can terminate it by typing ctrl-d or similar. The message "unable to get local issuer certificate" just means that your local openSSL doesn't have, or hasn't been configured to find, an appropriate root certificate for the chain presented.
This isn't necessarily a problem with the server - if you care, research s_client's -CApath and -CAfile options.
What is important is that your certificate and the appropriate two chaining certificates appear in the output.

http://support.microsoft.com/kb/816794 ( installing new janet certs in server 2003 )

Repairing certificate store:
https://www.microsoft.com/technet/prodtechnol/windowsserver2003/library/iis/53dfdb5e-6106-4d99-85bb-da199bc27c7e.mspx

an example
openssl s_client -connect hostname.of.server:636

Encrypt and Decrypt File To encrypt files with OpenSSL is as simple as encrypting messages. The only difference is that instead of the echo command we use the -in option with the actual file we would like to encrypt and -out option, which will instruct OpenSSL to store the encrypted file under a given name:

$ openssl enc -aes-256-cbc -in /etc/services -out services.dat

To decrypt back our services file use:

$ openssl enc -aes-256-cbc -d -in services.dat > services.txt
enter aes-256-cbc decryption password:

Extracting Certificate and Private Key Files from a .pfx File

Procedure
    To extract all certificates from a pfx file and save in text file:
                openssl pkcs12 -nodes -in the_pfx_file.pfx  > thekeys.txt
 
    Take the file you exported (e.g. certname.pfx) and copy it to a system where you have OpenSSL installed. Note: the *.pfx file is in PKCS#12 format and includes both the certificate and the private key.
    Run the following command to export the private key: openssl pkcs12 -in certname.pfx -nocerts -out key.pem -nodes
    Run the following command to export the certificate: openssl pkcs12 -in certname.pfx -nokeys -out cert.pem
    Run the following command to remove the passphrase from the private key: openssl rsa -in key.pem -out server.key