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Barcodes produced in printer-centric mode may have a slightly different aspect from those pro-
duced in Optimized PostScript mode. This is due to the different types of 3rd party libraries being
used to generate the barcodes. However, all barcodes scan correctly.
Obtaining a certificate
Certificates are files that uniquely identify people and resources on the Internet. They are required to
enable secure, confidential communication between two entities.
For production purposes, it is highly recommended that you obtain a proper certificate issued by an offi-
cial Certificate Authority (CA).
Certificates can be obtained from many different commercial parties. If you use certificates for other
applications, you are likely already dealing with a Certificate Authority. Alternatively, you may turn to a
service like Let’s Encrypt, which provides an easy way of obtaining an official certificate for free (the
drawback is, you will have to renew the certificate more frequently).
Certificates are associated with a specific domain, so this will usually be handled by the person man-
aging that domain, typically someone in your IT department.
Sometimes a server has not been added to a domain - the OL Connect Server, for example -, or a local
domain is used for internal servers. In cases like these, the IT department could either manage and cre-
ate their own certificates, or use self-signed certificates.
Creating self-signed certificates
Self-signed certificates are public key certificates that are not issued by a trusted certificate authority.
Because of this, they are more used in testing than for actual deployment.
The easiest way to create a self-signed certificate is to simply go to an online certificate generator such
as selfsignedcertificate.com. Just type a server name, domain, or even just localhost, and download
the certificate and its private key.
Alternatively, you can create your own certificate locally by using OpenSSL. Getting OpenSSL may be
a bit of a pain; you have to either compile it yourself, or get it from a third party that you trust. A nice
source can be Git, as that has OpenSSL bundled.
Creating the certificate and private key is a single command. For example:
openssl req -x509 -sha256 -days 365 -newkey rsa:2048 -keyout privateKey.key
-out certificate.crt
Or like this, if you don’t want a password for the key file:
openssl req -x509 -sha256 -nodes -days 365 -newkey rsa:2048 -keyout
privateKey.key -out certificate.crt
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