I’ve been a user of PGP or GnuPG for quite some years, on and off. It’s a way of encrypting email such that it is unreadable by anyone except the person it is sent to. The reason is simple: I want email to be more secure, intended only for its recipient and no-one else. In an age when email can be tampered with too, I want people to be able to tell that the email I have sent them is truly from me and no-one else.
A simple straightforward guide is here, suitable for Windows and Linux users. It helps you set up GnuPG, Thunderbird and Enigmail, probably the best combination for encrypted mail as things stand.
However, the fact that SHA-1 has allegedly been broken does change things somewhat. SHA-1 isn’t encryption per se: it’s a way of verifying data is as it was originally intended and has not been tampered with or forged. It forms an important part of the PGP system.
It now looks like it could be broken, given long enough and sufficient computer power (as opposed to ridiculous amounts of time and unimaginable computer power).
I feel it is important that email can be put in an “envelope” marked: “For recipient’s eyes only”. All power to the people who are trying to make that happen, and ensure that others can’t get into that “envelope” unauthorised.