Fix segfault on bad cmdline -f (sender) argument. Bug 2541

[users/heiko/exim.git] / doc / doc-txt / GnuTLS-FAQ.txt

diff --git a/doc/doc-txt/GnuTLS-FAQ.txt b/doc/doc-txt/GnuTLS-FAQ.txt
index 897087582a8793b1696eb74034334e16d448fa94..ab4e5aaa6a88e549304923d5d75c2a271feef939 100644 (file)
--- a/doc/doc-txt/GnuTLS-FAQ.txt
+++ b/doc/doc-txt/GnuTLS-FAQ.txt
@@ -6,7 +6,7 @@ Using Exim 4.80+ with GnuTLS
 (3) I'm seeing:
     "(gnutls_handshake): A TLS packet with unexpected length was received"
     Why?
 (3) I'm seeing:
     "(gnutls_handshake): A TLS packet with unexpected length was received"
     Why?

-(4) What's the deal with MD5?
+(4) What's the deal with MD5?  (And SHA-1?)

 (5) What happened to gnutls_require_kx / gnutls_require_mac /
     gnutls_require_protocols?
 (6) What's the deal with tls_dh_max_bits?  What's DH?
 (5) What happened to gnutls_require_kx / gnutls_require_mac /
     gnutls_require_protocols?
 (6) What's the deal with tls_dh_max_bits?  What's DH?


@@ -89,8 +89,8 @@ option fixes the problem, this was the cause.  See Q6.
 
 
 
 
 
 

-(4): What's the deal with MD5?
-------------------------------
+(4): What's the deal with MD5?  (And SHA-1?)
+--------------------------------------------

 
 MD5 is a hash algorithm.  Hash algorithms are used to reduce a lot of data
 down to a fairly short value, which is supposed to be extremely hard to
 
 MD5 is a hash algorithm.  Hash algorithms are used to reduce a lot of data
 down to a fairly short value, which is supposed to be extremely hard to


@@ -119,6 +119,10 @@ the ongoing costs of proving a trust relationship, such as providing
 revocation protocols.  This is just another of those ongoing costs you have
 already paid for.
 
 revocation protocols.  This is just another of those ongoing costs you have
 already paid for.
 

+The same has happened to SHA-1: there are real-world collision attacks against
+SHA-1, so SHA-1 is mostly defunct in certificates.  GnuTLS no longer supports
+its use in TLS certificates.
+

 
 
 (5): ... gnutls_require_kx / gnutls_require_mac / gnutls_require_protocols?
 
 
 (5): ... gnutls_require_kx / gnutls_require_mac / gnutls_require_protocols?