Hashing routines
================
-Libucw contains two hash algorithms, MD5 (RFC 1321) and SHA1 (RFC
-3174).
+Libucw contains two cryptographic hash algorithms: MD5 (RFC 1321) and SHA1 (RFC
+3174). A SHA1-HMAC (RFC 2104) message authentication is available.
+
+There are non-cryptographic hashes as well.
+
+<<crypto,Cryptographic ones>>:
- <<md5,MD5>>
- <<sha1,SHA1>>
-- <<usage,Usage>>
+- <<sha1:sha1_hmac(),SHA1_HMAC>>
+- <<usage,Common usage>>
+
+<<checksum,Checksums>>:
+- <<crypto:adler,Adler-32>>
+
+<<nocrypto,Non-cryptographic ones>>:
+
+- <<strhash,String & block hashes>>
+- <<inthash,Integer hashes>>
+
+[[crypto]]
+Cryptographic hashes
+--------------------
[[md5]]
MD5
----
+~~~
!!ucw/md5.h
[[sha1]]
SHA1
-----
+~~~~
!!ucw/sha1.h
[[usage]]
-Usage
------
+Common usage
+~~~~~~~~~~~~
There are two ways you can use the hashing routines.
byte output[MD5_SIZE];
memcpy(output, md5_final(&c), MD5_SIZE);
-SHA1 has the same interface, so both ways work to it as well.
+SHA1 has the same interface, so the same two ways apply.
See also <<string:mem_to_hex()>>.
+
+[[checksum]]
+Checksums
+---------
+
+Their purpose is checking against random data changes, hardware
+failures and alike. They are not to be used against aimed attacks.
+
+The <<compress:adler,Adler-32 checksum>> is documented in the
+<<compression,compression capter>>.
+
+[[nocrypto]]
+Non-cryptographic hashes
+------------------------
+
+They are usually used to identify values in hash tables.
+
+All these functions expect to be moduled by the size of a hash table.
+The size should be a prime number (it gives better distribution).
+
+!!ucw/hashfunc.h