* hmac-md5.c (hmac_md5): Add comments, suggested by Bruno Haible

<bruno@clisp.org>.
* hmac-sha1.c (hmac_sha1): Likewise.

diff --git a/lib/ChangeLog b/lib/ChangeLog
index ae05d1b..5206f03 100644 (file)
--- a/lib/ChangeLog
+++ b/lib/ChangeLog
@@ -1,5 +1,10 @@
 2005-10-21  Simon Josefsson  <jas@extundo.com>
 
+       * hmac-md5.c (hmac_md5): Add comments, suggested by Bruno Haible
+       <bruno@clisp.org>.
+
+       * hmac-sha1.c (hmac_sha1): Likewise.
+
        * crc.c (crc32_update): Actually use crc parameter, suggested by
        Bruno Haible <bruno@clisp.org>.
 

diff --git a/lib/hmac-md5.c b/lib/hmac-md5.c
index ecd0714..816762b 100644 (file)
--- a/lib/hmac-md5.c
+++ b/lib/hmac-md5.c
@@ -41,6 +41,8 @@ hmac_md5 (const void *key, size_t keylen,
   char block[64];
   char innerhash[16];
 
+  /* Reduce the key's size, so that it becomes <= 64 bytes large.  */
+
   if (keylen > 64)
     {
       struct md5_ctx keyhash;
@@ -53,6 +55,8 @@ hmac_md5 (const void *key, size_t keylen,
       keylen = 16;
     }
 
+  /* Compute INNERHASH from KEY and IN.  */
+
   md5_init_ctx (&inner);
 
   memset (block, IPAD, sizeof (block));
@@ -63,6 +67,8 @@ hmac_md5 (const void *key, size_t keylen,
 
   md5_finish_ctx (&inner, innerhash);
 
+  /* Compute result from KEY and INNERHASH.  */
+
   md5_init_ctx (&outer);
 
   memset (block, OPAD, sizeof (block));

diff --git a/lib/hmac-sha1.c b/lib/hmac-sha1.c
index 9c95791..f7a3fda 100644 (file)
--- a/lib/hmac-sha1.c
+++ b/lib/hmac-sha1.c
@@ -41,6 +41,8 @@ hmac_sha1 (const void *key, size_t keylen,
   char block[64];
   char innerhash[20];
 
+  /* Reduce the key's size, so that it becomes <= 64 bytes large.  */
+
   if (keylen > 64)
     {
       struct sha1_ctx keyhash;
@@ -53,6 +55,8 @@ hmac_sha1 (const void *key, size_t keylen,
       keylen = 20;
     }
 
+  /* Compute INNERHASH from KEY and IN.  */
+
   sha1_init_ctx (&inner);
 
   memset (block, IPAD, sizeof (block));
@@ -63,6 +67,8 @@ hmac_sha1 (const void *key, size_t keylen,
 
   sha1_finish_ctx (&inner, innerhash);
 
+  /* Compute result from KEY and INNERHASH.  */
+
   sha1_init_ctx (&outer);
 
   memset (block, OPAD, sizeof (block));