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 > ssl-bundle.crt

note: “domain_com.crt” is your End Entity certificate file
“” 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 >

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 files using any text editor.

  2. Copy all the content of domainname.crt and paste it on the top of 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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