+++ This prototype got merged with and is continued at OpenPGP.js +++

The content of this side is left for reference reasons.

GPG4Browsers is a prototype implementation of the OpenPGP Message Format [RFC 4880]. The implementation is currently written as Chrome Browser Extension with a Googlemail integration for encrypting, decrypting or signing emails.

The OpenPGP implementation supports all asymmetric, symmetric ciphers (except IDEA) and hash functions specified in the standard and implements the following use cases:

The implementation is compatible with the GnuPG implementation standard settings except the standard compression used. To create a compatible message in GnuPG use the option --compress-algo none.

Limitations and Licensing

The code is released under the GNU Lesser Public License.

The implementation currently not supports:


The following code of other projects has been modified or used for this project:

AES libraryHerbert Hanewinkel
CAST5 with modifications from Herbert Hanewinkel
DES libraryPaul Tero with modification from Michael Hayworth
Blowfish librarynklein software (Patrick Fleckenstein)
Twofish libraryAtsushi Oka
SHA libraryBrian Turek
MD5 libraryHenri Torgemane
RIPEMD/160Derek Buitenhuis
Base64 encoding libraryHerbert Hanewinkel
JS BigNum libraryTom Wu
OpenPGP CFBPartially from Herbert Hanewinkel
UI libraryThe jQuery Project

Get the code

The current release is available as ZIP archive here.

The source code is located in the following subversion repository:


To install the extension perform the following steps:


For using the Browser extension you need to import private and public OpenPGP keys. This can be done by using the extensions options page linked at chrome://extensions. The options page allows to search keys on a public key server which exposes the service at port 80.



The source code is documented using JavaDoc annotation. An architectural overview as well as example code can be found in the Developer Documentation (PDF).


For questions, comments or contributions please contact