Is a SSL key file binary?

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http://serverfault.com – I'm trying to install a SSL with my nginx setup. I configured nginx with those two files, but it doesn't work. Nginx complained the following error message. SSL: error:0906D06C:PEM routines:PEM_read_bio:no start line error:140DC009:SSL routines:SSL_CTX_use_certificate_chain_file:PEM lib I looked up google then found out that Nginx can't read either the cert or key file. I opened the cert file and everything looked good. When I opened the key file then I realized it is a binary file. is this normal? I thought a key file is just a plain text file. (HowTos)