encrypt and sign utility
Download from PortableApps.com
GPG Plugin Portable can run from a cloud folder, external drive, or local folder without installing into Windows. It's even better with the PortableApps.com Platform for easy installs and automatic updates.
GnuPG allows to encrypt and sign your data and communication, features a versatile key management system as well as access modules for all kinds of public key directories. Both Thunderbird Portable and SeaMonkey Portable will utilize GPG Plugin Portable automatically from the CommonFiles directory. It can also be installed directly to ThunderbirdPortable\App\gpg and SeaMonkeyPortable\App\gpg