Cisco Cisco Expressway
Appendix 3: Converting a DER Certificate File to PEM Format
A private key, root (CA) certificate and the server / client certificate can be generated using third-party tools (or
purchased from a certificate authority), and may be generated as PEM (required format, extension .pem) or DER
(extension .cer) format files.
purchased from a certificate authority), and may be generated as PEM (required format, extension .pem) or DER
(extension .cer) format files.
Certificates must be in PEM format for use on the Expressway. Conversion from DER to PEM format can be done in
one of two ways, either using OpenSSL or Windows, as documented in the following sections.
one of two ways, either using OpenSSL or Windows, as documented in the following sections.
Converting a DER certificate file to a PEM file using OpenSSL
To convert from DER to PEM format, on a system running openssl, execute the command:
openssl x509 -in <filename>.cer -inform DER -out <filename>.pem -outform PEM
Converting a DER certificate file to a PEM file using Microsoft Windows
To convert from DER to PEM format using Microsoft Windows:
1.
Double click on the DER file to convert (this will likely have a ‘.cer’ extension).
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