Add an internal-representation no-op function.

[u/mdw/catacomb] / hashsum.1

diff --git a/hashsum.1 b/hashsum.1
index 96e19ae..f500d25 100644 (file)
--- a/hashsum.1
+++ b/hashsum.1
@@ -201,6 +201,13 @@ The
 .B hashsum
 program understands several hashing algorithms:
 .TP
+.BR md2
+Designed by Ron Rivest, although I don't know when, and described in
+RFC1319, MD2 is a really old and slow hash function.  Its security is
+suspect too: only its checksum stands between it and collision-finding
+attacks.  Use of MD2 is not recommended, though it's still used in
+various standards.
+.TP
 .BR md4 " and " md5
 Designed by Ron Rivest in 1990 and 1992 respectively and described in
 RFCs 1186, 1320 and 1321, these two early hash functions are efficient
@@ -231,11 +238,16 @@ drop-in replacement for MD4, MD5 and the old RIPEMD.  The 256 and
 .B tiger
 Designed by Ross Anderson and Eli Biham to take advantage of 64-bit
 processors, Tiger seems to be an efficient and strong hash function.
-Its 192-bit output is wider than that of any other algorithm supported
-by
-.BR hashsum .
 It's a relatively new algorithm, however, and should probably be
 approached with an open-minded caution.
+.TP
+.BR sha256 ", " sha384 " and " sha512
+Designed by the US National Security Agency to provide security
+commensurate with the Advanced Encryption Standard, these hash functions
+provide long outputs.  SHA-256 is fairly quick, though the longer
+variants are slower on 32-bit hardware since they require 64-bit
+arithmetic.  They're all very new at the moment, and should be
+approached with an open-minded caution.
 .PP
 The default hashing algorithm is determined by looking at the name by
 which it was invoked passed to it in