emboss	2012-02-08 09:29:26 +0900 (Wed, 08 Feb 2012)

  New Revision: 34463

  http://svn.ruby-lang.org/cgi-bin/viewvc.cgi?view=rev&revision=34463

  Log:
    * ext/openssl/ossl_cipher.c: Add warning about key as IV.

  Modified files:
    trunk/ChangeLog
    trunk/ext/openssl/ossl_cipher.c

Index: ChangeLog
===================================================================
--- ChangeLog	(revision 34462)
+++ ChangeLog	(revision 34463)
@@ -1,3 +1,7 @@
+Wed Feb 08 09:19:00 2012  Martin Bosslet  <Martin.Bosslet@g...>
+
+	* ext/openssl/ossl_cipher.c: Add warning about key as IV.
+
 Tue Feb  7 20:08:12 2012  Ayumu AIZAWA  <ayumu.aizawa@g...>
 
 	* error.c (exc_inspect): Fix typo. patch from Trent Ogren
Index: ext/openssl/ossl_cipher.c
===================================================================
--- ext/openssl/ossl_cipher.c	(revision 34462)
+++ ext/openssl/ossl_cipher.c	(revision 34463)
@@ -686,6 +686,12 @@
      *  key = cipher.random_key
      *  iv = cipher.random_iv # also sets the generated IV on the Cipher
      *
+     *  Although the key is generally a random value, too, it is a bad choice
+     *  as an IV. There are elaborate ways how an attacker can take advantage
+     *  of such an IV. As a general rule of thumb, exposing the key directly
+     *  or indirectly should be avoided at all cost and exceptions only be
+     *  made with good reason. 
+     *
      * === Calling Cipher#final
      *
      * ECB (which should not be used) and CBC are both block-based modes.

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