X-Git-Url: http://git.chise.org/gitweb/?a=blobdiff_plain;f=README;h=a8fda71e91521b5572f53464a92440dc5492e1bf;hb=c165609a9c48703317640231336ce8fa9e2ee4e9;hp=e8f6d8b86244c60abc748e7c76d8d017895a6ac4;hpb=4b04dd2ba6edcbf209ef6a8c58bedac1b1342cae;p=elisp%2Fepg.git diff --git a/README b/README index e8f6d8b..a8fda71 100644 --- a/README +++ b/README @@ -24,7 +24,7 @@ Add the following line to your ~/.emacs (require 'epa-setup) -Then you can browse your keyring by M-x epa-list-keys. In addition, +Then you can browse your keyring by `M-x epa-list-keys'. In addition, you can do some cryptographic operations on dired. M-x dired @@ -34,21 +34,22 @@ you can do some cryptographic operations on dired. * Security consideration -** `call-process-region' writes data in region to a temporary file +** Passphrase may leak to a temporary file. `call-process-region' writes data in region to a temporary file. -EasyPG does *not* use `call-process-region' to communicate with a gpg +The EasyPG Library does not use `call-process-region' to communicate with a gpg subprocess. -** `(fillarray string 0)' is not enough to clear passphrases +** There is no way to clear passphrase safely. If Emacs crashes and dumps core, Lisp 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. +strings may be moved elsewhere in memory. Therefore, passphrase +caching in elisp is generally a bad idea. -Fortunately, there is gpg-agent to cache passphrases in more secure -way, so the EasyPG Library dares to disable passphrase caching. Elisp +The EasyPG Library dares to disable passphrase caching. Fortunately, +there is more secure way to cache passphrases - use gpg-agent. Elisp programs can set `epg-context-passphrase-callback' to cache user's -passphrases. +passphrases, it is not recommended though.