X-Git-Url: http://git.chise.org/gitweb/?a=blobdiff_plain;f=README;h=e231330cd6b256fdddcf68adf805ad03bd5bc6c7;hb=95ff40c9179c88308fe96e1adb0ef220b67f265c;hp=b3bca3904f6a47d267d93d851bbb57c63992ead3;hpb=06b8e756e7bb432c351d70489f6b0b66b865bb27;p=elisp%2Fepg.git diff --git a/README b/README index b3bca39..e231330 100644 --- a/README +++ b/README @@ -2,7 +2,7 @@ EasyPG is yet another GnuPG interface for Emacs. It consists of three parts: transparent file encryption utility, Gnus/PGG backend, and -easy-to-use elisp library to interact with GnuPG. +elisp library to interact with GnuPG. * Requirements @@ -16,43 +16,51 @@ easy-to-use elisp library to interact with GnuPG. * Quick start -** Transparent file encryption +** Installation -EasyPG provides transparent file encryption similar to crypt++, -alpaca.el, hedgehog. To try this feature, put (require 'epg-file) -in your ~/.emacs.el and C-x C-f ~/test.txt.gpg. +$ ./configure +$ sudo make install -** Using with Gnus/PGG +** Transparent file encryption utility + +EasyPG provides transparent file encryption utility similar to +crypt++, alpaca.el, hedgehog. To try this, add the following line to +your ~/.emacs and C-x C-f ~/test.txt.gpg. + +(require 'epg-file) + +** Gnus/PGG backend EasyPG provides an implementation of the backend interface of Gnus/PGG. To use EasyPG instead of pgg-gpg, install pgg-epg.el and -add the following line to your ~/.gnus +add the following line to your ~/.gnus. (setq pgg-scheme 'epg) * Advantages over other competitors -There are many competitors of EasyPG such as Mailcrypt, PGG, gpg.el, -etc. EasyPG has some advantages over them. +There are many competitors of EasyPG such as Mailcrypt, Gnus/PGG, +gpg.el, etc. EasyPG has some advantages over them. -** EasyPG avoides potential security flaws of Emacs. +** EasyPG avoides potential security flaws of Emacs -*** `call-process-region' writes data in region to temporary files. +*** `call-process-region' writes data in region to temporary files -`call-process-region' writes data in region to temporary files. PGG -and gpg.el use `call-process-region' to communicate with a gpg -subprocess. Your passphrases leak to the filesystem! +`call-process-region' writes data in region to temporary files. +EasyPG do _not_ use `call-process-region' to communicate with a gpg +subprocess. -*** There is no way to clear strings safely. +*** `(fillarray string 0)' is not enough to clear passphrases If Emacs crashed and dumps core, passphrase strings in memory are also dumped within the core file. `read-passwd' function clears passphrase strings by `(fillarray string 0)'. However, Emacs performs compaction in gc_sweep phase. If GC happens before `fillarray', passphrase -strings may be moved elsewhere in memory. It is recommended that as -soon as you are done with passphrase you should clear it manually. -However, PGG and gpg.el can keep passphrase strings in cache for a -while and this behavior is their default! +strings may be moved elsewhere in memory. + +Fortunately, there is gpg-agent to cache passphrases in more secure +way, so EasyPG dares _not_ to cache passphrase. Elisp programs can +set `epg-context-passphrase-callback' to cache user's passphrases. ** GnuPG features are directly accessible from Emacs