diff --git a/configure.ac b/configure.ac
index fa066432e..2e134be97 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1334,6 +1334,19 @@ then
 fi
 
 
+# Small Stack
+AC_ARG_ENABLE([smallstack],
+    [  --enable-smallstack     Enable Small Stack Usage (default: enabled)],
+    [ ENABLED_SMALL_STACK=$enableval ],
+    [ ENABLED_SMALL_STACK=yes ]
+    )
+
+if test "$ENABLED_SMALL_STACK" = "no"
+then
+    AM_CFLAGS="$AM_CFLAGS -DNO_SMALL_STACK"
+fi
+
+
 #valgrind
 AC_ARG_ENABLE([valgrind],
     [  --enable-valgrind       Enable valgrind for unit tests (default: disabled)],
@@ -1760,6 +1773,7 @@ echo "   * Supported Elliptic Curves: $ENABLED_SUPPORTED_CURVES"
 echo "   * All TLS Extensions:        $ENABLED_TLSX"
 echo "   * PKCS#7                     $ENABLED_PKCS7"
 echo "   * wolfSCEP                   $ENABLED_WOLFSCEP"
+echo "   * Small Stack:               $ENABLED_SMALL_STACK"
 echo "   * valgrind unit tests:       $ENABLED_VALGRIND"
 echo "   * LIBZ:                      $ENABLED_LIBZ"
 echo "   * Examples:                  $ENABLED_EXAMPLES"
diff --git a/ctaocrypt/benchmark/benchmark.c b/ctaocrypt/benchmark/benchmark.c
index 5dc28e004..2cccd362a 100644
--- a/ctaocrypt/benchmark/benchmark.c
+++ b/ctaocrypt/benchmark/benchmark.c
@@ -623,8 +623,7 @@ void bench_sha256(void)
     Sha256 hash;
     byte   digest[SHA256_DIGEST_SIZE];
     double start, total, persec;
-    int    i;
-    int    ret;
+    int    i, ret;
         
     ret = InitSha256(&hash);
     if (ret != 0) {
@@ -735,15 +734,28 @@ void bench_blake2(void)
     Blake2b b2b;
     byte    digest[64];
     double  start, total, persec;
-    int     i;
+    int     i, ret;
        
-    InitBlake2b(&b2b, 64); 
+    ret = InitBlake2b(&b2b, 64);
+    if (ret != 0) {
+        printf("InitBlake2b failed, ret = %d\n", ret);
+        return;
+    }
     start = current_time(1);
     
-    for(i = 0; i < numBlocks; i++)
-        Blake2bUpdate(&b2b, plain, sizeof(plain));
+    for(i = 0; i < numBlocks; i++) {
+        ret = Blake2bUpdate(&b2b, plain, sizeof(plain));
+        if (ret != 0) {
+            printf("Blake2bUpdate failed, ret = %d\n", ret);
+            return;
+        }
+    }
    
-    Blake2bFinal(&b2b, digest, 64);
+    ret = Blake2bFinal(&b2b, digest, 64);
+    if (ret != 0) {
+        printf("Blake2bFinal failed, ret = %d\n", ret);
+        return;
+    }
 
     total = current_time(0) - start;
     persec = 1 / total * numBlocks;
diff --git a/ctaocrypt/src/blake2b.c b/ctaocrypt/src/blake2b.c
index a3f4224fb..77b736d22 100644
--- a/ctaocrypt/src/blake2b.c
+++ b/ctaocrypt/src/blake2b.c
@@ -163,12 +163,25 @@ int blake2b_init_key( blake2b_state *S, const byte outlen, const void *key,
   if( blake2b_init_param( S, P ) < 0 ) return -1;
 
   {
+#ifndef NO_SMALL_STACK
+    byte* block;
+
+    block = (byte*)XMALLOC(BLAKE2B_BLOCKBYTES, NULL, DYNAMIC_TYPE_TMP_BUFFER);
+
+    if ( block == NULL ) return -1;
+#else
     byte block[BLAKE2B_BLOCKBYTES];
+#endif
+
     XMEMSET( block, 0, BLAKE2B_BLOCKBYTES );
     XMEMCPY( block, key, keylen );
     blake2b_update( S, block, BLAKE2B_BLOCKBYTES );
     secure_zero_memory( block, BLAKE2B_BLOCKBYTES ); /* Burn the key from */
-                                                     /*stack */
+                                                     /* memory */
+
+#ifndef NO_SMALL_STACK
+    XFREE(block, NULL, DYNAMIC_TYPE_TMP_BUFFER);
+#endif
   }
   return 0;
 }
@@ -176,9 +189,27 @@ int blake2b_init_key( blake2b_state *S, const byte outlen, const void *key,
 static int blake2b_compress( blake2b_state *S,
                              const byte block[BLAKE2B_BLOCKBYTES] )
 {
+  int i;
+
+#ifndef NO_SMALL_STACK
+  word64* m;
+  word64* v;
+
+  m = (word64*)XMALLOC(sizeof(word64) * 16, NULL, DYNAMIC_TYPE_TMP_BUFFER);
+
+  if ( m == NULL ) return -1;
+
+  v = (word64*)XMALLOC(sizeof(word64) * 16, NULL, DYNAMIC_TYPE_TMP_BUFFER);
+
+  if ( v == NULL )
+  {
+    XFREE(m, NULL, DYNAMIC_TYPE_TMP_BUFFER);
+    return -1;
+  }
+#else
   word64 m[16];
   word64 v[16];
-  int i;
+#endif
 
   for( i = 0; i < 16; ++i )
     m[i] = load64( block + i * sizeof( m[i] ) );
@@ -234,6 +265,12 @@ static int blake2b_compress( blake2b_state *S,
 
 #undef G
 #undef ROUND
+
+#ifndef NO_SMALL_STACK
+  XFREE(m, NULL, DYNAMIC_TYPE_TMP_BUFFER);
+  XFREE(v, NULL, DYNAMIC_TYPE_TMP_BUFFER);
+#endif
+
   return 0;
 }
 
@@ -250,7 +287,9 @@ int blake2b_update( blake2b_state *S, const byte *in, word64 inlen )
       XMEMCPY( S->buf + left, in, (word)fill ); /* Fill buffer */
       S->buflen += fill;
       blake2b_increment_counter( S, BLAKE2B_BLOCKBYTES );
-      blake2b_compress( S, S->buf ); /* Compress */
+
+      if ( blake2b_compress( S, S->buf ) < 0 ) return -1; /* Compress */
+
       XMEMCPY( S->buf, S->buf + BLAKE2B_BLOCKBYTES, BLAKE2B_BLOCKBYTES );
               /* Shift buffer left */
       S->buflen -= BLAKE2B_BLOCKBYTES;
@@ -278,7 +317,9 @@ int blake2b_final( blake2b_state *S, byte *out, byte outlen )
   if( S->buflen > BLAKE2B_BLOCKBYTES )
   {
     blake2b_increment_counter( S, BLAKE2B_BLOCKBYTES );
-    blake2b_compress( S, S->buf );
+
+    if ( blake2b_compress( S, S->buf ) < 0 ) return -1;
+
     S->buflen -= BLAKE2B_BLOCKBYTES;
     XMEMCPY( S->buf, S->buf + BLAKE2B_BLOCKBYTES, (word)S->buflen );
   }
@@ -287,7 +328,7 @@ int blake2b_final( blake2b_state *S, byte *out, byte outlen )
   blake2b_set_lastblock( S );
   XMEMSET( S->buf + S->buflen, 0, (word)(2 * BLAKE2B_BLOCKBYTES - S->buflen) );
          /* Padding */
-  blake2b_compress( S, S->buf );
+  if ( blake2b_compress( S, S->buf ) < 0 ) return -1;
 
   for( i = 0; i < 8; ++i ) /* Output full hash to temp buffer */
     store64( buffer + sizeof( S->h[i] ) * i, S->h[i] );
@@ -318,9 +359,9 @@ int blake2b( byte *out, const void *in, const void *key, const byte outlen,
     if( blake2b_init( S, outlen ) < 0 ) return -1;
   }
 
-  blake2b_update( S, ( byte * )in, inlen );
-  blake2b_final( S, out, outlen );
-  return 0;
+  if ( blake2b_update( S, ( byte * )in, inlen ) < 0) return -1;
+
+  return blake2b_final( S, out, outlen );
 }
 
 #if defined(BLAKE2B_SELFTEST)
@@ -340,7 +381,11 @@ int main( int argc, char **argv )
   for( word32 i = 0; i < KAT_LENGTH; ++i )
   {
     byte hash[BLAKE2B_OUTBYTES];
-    blake2b( hash, buf, key, BLAKE2B_OUTBYTES, i, BLAKE2B_KEYBYTES );
+    if ( blake2b( hash, buf, key, BLAKE2B_OUTBYTES, i, BLAKE2B_KEYBYTES ) < 0 )
+    {
+      puts( "error" );
+      return -1;
+    }
 
     if( 0 != memcmp( hash, blake2b_keyed_kat[i], BLAKE2B_OUTBYTES ) )
     {
diff --git a/ctaocrypt/src/hmac.c b/ctaocrypt/src/hmac.c
index 9afae366d..c383dc0fb 100644
--- a/ctaocrypt/src/hmac.c
+++ b/ctaocrypt/src/hmac.c
@@ -103,7 +103,7 @@ static int InitHmac(Hmac* hmac, int type)
         
         #ifdef HAVE_BLAKE2 
         case BLAKE2B_ID:
-            InitBlake2b(&hmac->hash.blake2b, BLAKE2B_256);
+            ret = InitBlake2b(&hmac->hash.blake2b, BLAKE2B_256);
         break;
         #endif
         
@@ -238,8 +238,14 @@ int HmacSetKey(Hmac* hmac, int type, const byte* key, word32 length)
                 XMEMCPY(ip, key, length);
             }
             else {
-                Blake2bUpdate(&hmac->hash.blake2b, key, length);
-                Blake2bFinal(&hmac->hash.blake2b, ip, BLAKE2B_256);
+                ret = Blake2bUpdate(&hmac->hash.blake2b, key, length);
+                if (ret != 0)
+                    return ret;
+
+                ret = Blake2bFinal(&hmac->hash.blake2b, ip, BLAKE2B_256);
+                if (ret != 0)
+                    return ret;
+
                 length = BLAKE2B_256;
             }
         }
@@ -306,8 +312,10 @@ static int HmacKeyInnerHash(Hmac* hmac)
 
         #ifdef HAVE_BLAKE2 
         case BLAKE2B_ID:
-            Blake2bUpdate(&hmac->hash.blake2b,
+            ret = Blake2bUpdate(&hmac->hash.blake2b,
                                          (byte*) hmac->ipad,BLAKE2B_BLOCKBYTES);
+            if (ret != 0)
+                return ret;
         break;
         #endif
 
@@ -375,7 +383,9 @@ int HmacUpdate(Hmac* hmac, const byte* msg, word32 length)
 
         #ifdef HAVE_BLAKE2 
         case BLAKE2B_ID:
-            Blake2bUpdate(&hmac->hash.blake2b, msg, length);
+            ret = Blake2bUpdate(&hmac->hash.blake2b, msg, length);
+            if (ret != 0)
+                return ret;
         break;
         #endif
 
@@ -506,13 +516,24 @@ int HmacFinal(Hmac* hmac, byte* hash)
         #ifdef HAVE_BLAKE2 
         case BLAKE2B_ID:
         {
-            Blake2bFinal(&hmac->hash.blake2b, (byte*) hmac->innerHash,
+            ret = Blake2bFinal(&hmac->hash.blake2b, (byte*) hmac->innerHash,
                          BLAKE2B_256);
-            Blake2bUpdate(&hmac->hash.blake2b,
+            if (ret != 0)
+                return ret;
+
+            ret = Blake2bUpdate(&hmac->hash.blake2b,
                                  (byte*) hmac->opad, BLAKE2B_BLOCKBYTES);
-            Blake2bUpdate(&hmac->hash.blake2b,
+            if (ret != 0)
+                return ret;
+
+            ret = Blake2bUpdate(&hmac->hash.blake2b,
                                  (byte*) hmac->innerHash, BLAKE2B_256);
-            Blake2bFinal(&hmac->hash.blake2b, hash, BLAKE2B_256);
+            if (ret != 0)
+                return ret;
+
+            ret = Blake2bFinal(&hmac->hash.blake2b, hash, BLAKE2B_256);
+            if (ret != 0)
+                return ret;
         }
         break;
         #endif
diff --git a/ctaocrypt/test/test.c b/ctaocrypt/test/test.c
index c499d0728..7e315cec4 100644
--- a/ctaocrypt/test/test.c
+++ b/ctaocrypt/test/test.c
@@ -919,15 +919,23 @@ int blake2b_test(void)
     Blake2b b2b;
     byte    digest[64];
     byte    input[64];
-    int     i;
+    int     i, ret;
 
     for (i = 0; i < (int)sizeof(input); i++)
         input[i] = (byte)i;
 
     for (i = 0; i < BLAKE2_TESTS; i++) {
-        InitBlake2b(&b2b, 64);
-        Blake2bUpdate(&b2b, input, i);
-        Blake2bFinal(&b2b, digest, 64);
+        ret = InitBlake2b(&b2b, 64);
+        if (ret != 0)
+            return -4002;
+
+        ret = Blake2bUpdate(&b2b, input, i);
+        if (ret != 0)
+            return -4003;
+
+        ret = Blake2bFinal(&b2b, digest, 64);
+        if (ret != 0)
+            return -4004;
 
         if (memcmp(digest, blake2b_vec[i], 64) != 0) {
             return -300 - i;
@@ -969,15 +977,15 @@ int sha256_test(void)
 
     ret = InitSha256(&sha);
     if (ret != 0)
-        return -4003;
+        return -4005;
 
     for (i = 0; i < times; ++i) {
         ret = Sha256Update(&sha, (byte*)test_sha[i].input,(word32)test_sha[i].inLen);
         if (ret != 0)
-            return -4004;
+            return -4006;
         ret = Sha256Final(&sha, hash);
         if (ret != 0)
-            return -4005;
+            return -4007;
 
         if (memcmp(hash, test_sha[i].output, SHA256_DIGEST_SIZE) != 0)
             return -10 - i;