How do I create a message digest using openssl?

The openssl tool has a dgst command which creates message digests. Here’s an example:

$ echo 'hello world' | openssl dgst -sha512 -hex
db3974a97f2407b7cae1ae637c0030687a11913274d578492558e39c16c017de84eacdc8c62fe34ee4e12b4b1428817f09b6a2760c3f8a664ceae94d2434a593

Various flags change the hash algorithm, e.g. -sha1.

A useful flag is -hmac, which lets you sign the content with a shared password:

$ echo 'hello world' | openssl dgst -sha1 -hex -hmac secret_password_1
61c587ccf0d9feebbe95fa866f003a1ae7651f8f

I wrote this because I'm learning SSL, starting by going through the CLI tool commands This post is my own, and not associated with my employer.