Here's a short example how to generate a HMAC SHA256 hash (via passphrase). It's good to "sign" messages as a passphrase is used to hash a message,
Taken from: https://techtutorialsx.com/2018/01/25/esp32-arduino-applying-the-hmac-sha-256-mechanism/
Public hmackey(255) As Byte
Wikipedia: Google Authenticator
Most websites where you have to log in offer to protect your account by using a multi-factor authentication. Here you can use an app like Google Authenticator (GA) which shows a 6 or 8 digit number which you have to type in when you log in.
How it works:
Was recently requested to look at this by a friend, for encryption
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