How to Merge or Concatenate your SSL Certificates and Private Key in a single file

February 11, 2020 in SSL Technical FAQs

If you would like to move your certificate(s) into a bundle file, you can use a cat command in a Linux bash

example: cat domain_com.crt domain_com.ca-bundle.crt > ssl-bundle.crt

note: “domain_com.crt” is your End Entity certificate file
“domain_com.ca-bundle.crt” is your Root and Intermediate certificates bundled in this file.


In the event you have received the root and intermediate certificates separately, run the following command.
example: cat domain_com.crt USERTrustRSAAddTrustCA.crt AddTrustExternalCARoot.crt > domain_com.ca-bundle.crt


If you are using a GUI based Text Editor (such as; Notepad)

  • Here is how to concatenate the certificate files into single bundle file:

  1. Open domainname.crt and domainname.ca-bundle files using any text editor.

  2. Copy all the content of domainname.crt and paste it on the top of domainname.ca-bundle file.

  3. Save the file name as ‘ssl-bundle.crt’.

  • ​​​To concatenate your certificate with your private key:

1. Generate CSR

openssl req -new -newkey rsa:2048 -nodes -keyout path:\server.key -out path:\server_csr.txt

2. Download the certificate with your chain from SCM (eg: my_certificate.cer)
3. Concatenate the certificates with your private key:

openssl pkcs12 -export -out path:\[new cert bundle name].pfx -inkey path:\server.key -in path:\my_certificate.cer

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