--- gvpe/src/hkdf.C	2013/07/16 16:44:36	1.1
+++ gvpe/src/hkdf.C	2016/06/30 16:31:00	1.6
@@ -1,6 +1,6 @@
 /*
     hkdf.C -- RFC 5869 HKDF implementation
-    Copyright (C) 2013      Marc Lehmann <gvpe@schmorp.de>
+    Copyright (C) 2013,2016 Marc Lehmann <gvpe@schmorp.de>
  
     This file is part of GVPE.
 
@@ -33,41 +33,31 @@
 
 #include <cstring>
 
+#include <openssl/opensslv.h>
 #include <openssl/rand.h>
 #include <openssl/hmac.h>
 
+#include "crypto.h"
 #include "util.h"
 #include "hkdf.h"
 
-hkdf::hkdf (const void *salt, int len, const EVP_MD *hash)
+hkdf::hkdf (const void *salt, int len, const EVP_MD *xtr_hash)
+: salt (salt), salt_len (len)
 {
-  HMAC_CTX_init (&ctx);
-
-  if (!salt)
-    {
-      memset (prk, 0, sizeof prk);
-      salt = prk;
-      len  = EVP_MD_size (hash);
-    }
-
-  require (HMAC_Init_ex (&ctx, salt, len, hash, 0));
-}
-
-hkdf::~hkdf ()
-{
-  HMAC_CTX_cleanup (&ctx);
+  ctx.init (salt, salt_len, xtr_hash);
 }
 
 void
 hkdf::extract (const void *ikm, int len)
 {
-  require (HMAC_Update (&ctx, (u8 *)ikm, len));
+  ctx.add (ikm, len);
 }
 
 void
-hkdf::extract_done ()
+hkdf::extract_done (const EVP_MD *prf_hash)
 {
-  require (HMAC_Final (&ctx, prk, 0));
+  ctx.digest (prk);
+  ctx.init (salt, salt_len, prf_hash);
 }
 
 void
@@ -75,24 +65,22 @@
 {
   u8 tn[sizeof prk];
   u8 iter = 0;
-  int md_size = HMAC_size (&ctx);
+  int md_size = ctx.size ();
 
   while (len)
     {
-      require (HMAC_Init_ex (&ctx, prk, md_size, 0, 0));
+      ctx.init (prk, md_size);
 
       if (iter)
-        require (HMAC_Update (&ctx, tn, md_size));
-
-      require (HMAC_Update (&ctx, (u8 *)info, infolen));
+        ctx.add (tn, md_size);
 
+      ctx.add (info, infolen);
 
       ++iter;
       require (iter);
 
-      require (HMAC_Update (&ctx, &iter, 1));
-
-      require (HMAC_Final (&ctx, tn, 0));
+      ctx.add (&iter, 1);
+      ctx.digest (tn);
 
       int ol = len > md_size ? md_size : len;
 
@@ -119,13 +107,11 @@
     unhex (const char *hs)
     {
       l = 0;
-      p = 0;
+      p = s;
 
       if (!hs)
         return;
 
-      p = s;
-
       while (*hs)
         {
           int d1 = *hs >= '0' && *hs <= '9' ? *hs - '0' : *hs - 'a' + 10; ++hs;