Describe recently-added hash functions.

diff --git a/hashsum.1 b/hashsum.1
index 96e19ae..8e8c475 100644 (file)
--- a/hashsum.1
+++ b/hashsum.1
@@ -201,6 +201,13 @@ The
 .B hashsum
 program understands several hashing algorithms:
 .TP
 .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
 .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.
 .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.
 It's a relatively new algorithm, however, and should probably be
 approached with an open-minded caution.

+.TP
+.B 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
 .PP
 The default hashing algorithm is determined by looking at the name by
 which it was invoked passed to it in