The first step is to generate a hash of the message file:
$ openssl dgst -sha256 message.txt SHA256(message.txt)= eb96d1f89812bf4967d9fb4ead128c3b787272b7be21dd2529278db1128d559c
Both hash generation and signing can be done in a single step, as shown here. Note that privatekey.pem is generated in the steps provided previously:
$ openssl dgst -sha256 -sign privatekey.pem -out signature.bin message.txt
Now, let's display the directory showing the relevant files:
$ ls -ltr total 36 -rw-rw-r-- 1 drequinox drequinox 14 Sep 21 05:54 message.txt -rw-rw-r-- 1 drequinox drequinox 32 Sep 21 05:57 message.bin -rw-rw-r-- 1 drequinox drequinox 45 Sep 21 06:00 message.b64 -rw-rw-r-- 1 drequinox drequinox ...
