From e3899ababb9f96fc5e8ce6425ae705ba6f339513 Mon Sep 17 00:00:00 2001 From: "Dr. Stephen Henson" Date: Wed, 16 Apr 2014 12:15:43 +0100 Subject: [PATCH] Document -debug_decrypt option. (cherry picked from commit 0dd5b94aeb77c2982bdf6886962b7a8491c6c9ed) --- doc/apps/cms.pod | 15 +++++++++++++++ 1 file changed, 15 insertions(+) diff --git a/doc/apps/cms.pod b/doc/apps/cms.pod index a09588a18d..dd0fd862b4 100644 --- a/doc/apps/cms.pod +++ b/doc/apps/cms.pod @@ -90,6 +90,11 @@ decrypt mail using the supplied certificate and private key. Expects an encrypted mail message in MIME format for the input file. The decrypted mail is written to the output file. +=item B<-debug_decrypt> + +this option sets the B flag. This option should be used +with caution: see the notes section below. + =item B<-sign> sign mail using the supplied certificate and private key. Input file is @@ -446,6 +451,16 @@ Streaming is always used for the B<-sign> operation with detached data but since the content is no longer part of the CMS structure the encoding remains DER. +If the B<-decrypt> option is used without a recipient certificate then an +attempt is made to locate the recipient by trying each potential recipient +in turn using the supplied private key. To thwart the MMA attack +(Bleichenbacher's attack on PKCS #1 v1.5 RSA padding) all recipients are +tried whether they succeed or not and if no recipients match the message +is "decrypted" using a random key which will typically output garbage. +The B<-debug_decrypt> option can be used to disable the MMA attack protection +and return an error if no recipient can be found: this option should be used +with caution. For a fuller description see L). + =head1 EXIT CODES =over 4 -- 2.25.1