Configuring OpenSSL: Copying email Subject Alternative Name in openssl.cnf
OpenSSL is a robust, full-featured open-source toolkit that implements the Secure Sockets Layer (SSL) and Transport Layer Security (TLS) protocols. It is widely used to secure communication on the internet and is the backbone of many secure applications, including web servers, email servers, and VPNs.
What is a Subject Alternative Name?
A Subject Alternative Name (SAN) is a field in an X.509 digital certificate that allows additional domain names to be listed in the certificate, besides the primary domain name. SANs can be used for multiple purposes, including securing multiple domain names with a single certificate, securing both a domain name and an IP address, and securing wildcard domain names. One of the most common uses of the SAN field is to secure both the domain name and the email address of an organization.
Why Copy the email Subject Alternative Name in openssl.cnf?
When creating a Certificate Signing Request (CSR) for a digital certificate, it is important to include the email Subject Alternative Name in the CSR. This ensures that the email address of the organization is included in the certificate and can be used for secure email communication. However, manually entering the email Subject Alternative Name in the CSR can be error-prone and time-consuming. By copying the email Subject Alternative Name from the openssl.cnf file, you can ensure that the email address is included in the CSR and the resulting digital certificate, with minimal effort and maximum accuracy.
How to Copy the email Subject Alternative Name in openssl.cnf
To copy the email Subject Alternative Name in the openssl.cnf file, follow these steps:
- Open the openssl.cnf file in a text editor.
- Locate the section of the file that contains the email Subject Alternative Name. This section is typically near the bottom of the file and is labeled "req_distinguished_name" or "req_dn".
- Copy the email Subject Alternative Name line from the openssl.cnf file. The line should start with "[email]", followed by the email address in quotes. For example:
[email]
email = "[email protected]"
- Paste the copied email Subject Alternative Name line into the CSR. The line should be placed in the "Subject Alternative Name" section of the CSR. For example:
Subject Alternative Name:
email:[email protected]
Coming Soon: Signing the CSR with the email Subject Alternative Name
In a future article, we will show you how to sign the CSR with the email Subject Alternative Name and create a fully functional digital certificate. Stay tuned for more information on this exciting topic!
- OpenSSL is a widely used open-source toolkit for implementing SSL and TLS protocols.
- A Subject Alternative Name is a field in a digital certificate that allows additional domain names to be listed, including the email address of the organization.
- Copying the email Subject Alternative Name from the openssl.cnf file ensures that it is included in the CSR and the resulting digital certificate.
References
-
Network Security with OpenSSL: Updated for SSLv3/TLSv1
Joseph Steinberg
Prentice Hall
-
Configuring OpenSSL for SSL/TLS: Common Tasks and Best Practices
Chris Sanders
https://www.digitalocean.com/community/tutorials/configuring-openssl-for-ssl-tls
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OpenSSL Documentation
The OpenSSL Project