X-Git-Url: http://erislabs.net/gitweb/?a=blobdiff_plain;f=lib%2Fhmac-sha1.c;h=f7a3fda43eae4884cb12da8dc4c2b1ff78022b11;hb=fdba88ca5c48680a219e742f0b3d480daf74703d;hp=9c95791295b50ab26ee9818dd9549f3ab06c0c47;hpb=11ad180881e62f7d8758936af419c2cc88e9cf79;p=gnulib.git

diff --git a/lib/hmac-sha1.c b/lib/hmac-sha1.c
index 9c9579129..f7a3fda43 100644
--- 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));