Install hashcash by entering the following commands in the terminal:
sudo apt update sudo apt install hashcash
Description:
postage payment scheme for email based on hash calculations
Hash cash is a payment scheme that uses CPU cycles as the form of payment. This can be used as a counter-measure for junk email (spam) by using the hash cash token as a proof of payment for each email that you sent.
Version: 1.21-2
Section: universe/mail