GnuPG/PGP signature, short explanation

»What is the .asc file?« This explanation is intended to be copied as-is into emails when someone asks about your signature.

The .asc file is a signature which can be used to verify that the email was really sent by me and wasn’t tampered with.[1] It can be verified with standard email security tools like Enigmail[2], Gpg4win[3] or MacGPG[4] - and others tools supporting OpenPGP[5].

Best wishes,
Arne

[1]: For further information on signatures see
    https://www.gnupg.org/gph/en/manual/x135.html

[2]: Enigmail enables secure communication in Thunderbird:
    https://addons.mozilla.org/de/thunderbird/addon/enigmail/

[3]: GPG4win provides secure encryption for Windows:
    http://gpg4win.org/download.html

[4]: MacGPG provides encryption for MacOSX:
    https://gpgtools.org/

[5]: Encryption for other systems is available from the GnuPG website:
    https://www.gnupg.org/download/