Add Generate A Random Secret Value With OpenSSL as a Unix TIL

unix/generate-a-random-secret-value-with-openssl.md

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+# Generate A Random Secret Value With OpenSSL
+
+The `openssl` command can generate a random hex-based value like so:
+
+```bash
+❯ openssl rand -hex 32
+101142ffaf1c6b14395cec5592f6f3739d5ee282a9db27ec2d7ad879540c16a2
+```
+
+This is useful if I need to generate a secret key value for authentication in a
+feature I'm building. For example, I'm working on a dedicated MCP server that
+can only be accessed by a 3rd-party messaging interface. I need to only allow
+requests to the MCP endpoint that have a valid secret key. I can use the above
+command to generate unique values for both local testing and the actual secret
+that ends up in our production vault.
+
+See `man openssl` for more details.