From aa3854e33d898885d067b5055d7e0f0db38a9c0d Mon Sep 17 00:00:00 2001 From: emboss Date: Wed, 8 Feb 2012 00:29:26 +0000 Subject: * ext/openssl/ossl_cipher.c: Add warning about key as IV. git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@34463 b2dd03c8-39d4-4d8f-98ff-823fe69b080e --- ext/openssl/ossl_cipher.c | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'ext') diff --git a/ext/openssl/ossl_cipher.c b/ext/openssl/ossl_cipher.c index 101ea052fa..4e758b6a26 100644 --- a/ext/openssl/ossl_cipher.c +++ b/ext/openssl/ossl_cipher.c @@ -686,6 +686,12 @@ Init_ossl_cipher(void) * 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. -- cgit v1.2.3