diff --git a/lib/vtls/darwinssl.c b/lib/vtls/darwinssl.c
index f00a10053..ab3224c50 100644
--- a/lib/vtls/darwinssl.c
+++ b/lib/vtls/darwinssl.c
@@ -2780,7 +2780,7 @@ static void Curl_darwinssl_sha256sum(const unsigned char *tmp, /* input */
                                      unsigned char *sha256sum, /* output */
                                      size_t sha256len)
 {
-  assert(sha256len >= SHA256_DIGEST_LENGTH);
+  assert(sha256len >= CURL_SHA256_DIGEST_LENGTH);
   (void)CC_SHA256(tmp, (CC_LONG)tmplen, sha256sum);
 }
 
diff --git a/lib/vtls/vtls.c b/lib/vtls/vtls.c
index f15760342..a1a301e7f 100644
--- a/lib/vtls/vtls.c
+++ b/lib/vtls/vtls.c
@@ -815,13 +815,14 @@ CURLcode Curl_pin_peer_pubkey(struct Curl_easy *data,
     }
 
     /* compute sha256sum of public key */
-    sha256sumdigest = malloc(SHA256_DIGEST_LENGTH);
+    sha256sumdigest = malloc(CURL_SHA256_DIGEST_LENGTH);
     if(!sha256sumdigest)
       return CURLE_OUT_OF_MEMORY;
     Curl_ssl->sha256sum(pubkey, pubkeylen,
-                        sha256sumdigest, SHA256_DIGEST_LENGTH);
+                        sha256sumdigest, CURL_SHA256_DIGEST_LENGTH);
     encode = Curl_base64_encode(data, (char *)sha256sumdigest,
-                                SHA256_DIGEST_LENGTH, &encoded, &encodedlen);
+                                CURL_SHA256_DIGEST_LENGTH, &encoded,
+                                &encodedlen);
     Curl_safefree(sha256sumdigest);
 
     if(encode)
diff --git a/lib/vtls/vtls.h b/lib/vtls/vtls.h
index 3c8e32104..f1a11ea58 100644
--- a/lib/vtls/vtls.h
+++ b/lib/vtls/vtls.h
@@ -7,7 +7,7 @@
  *                            | (__| |_| |  _ <| |___
  *                             \___|\___/|_| \_\_____|
  *
- * Copyright (C) 1998 - 2016, Daniel Stenberg, <daniel@haxx.se>, et al.
+ * Copyright (C) 1998 - 2017, Daniel Stenberg, <daniel@haxx.se>, et al.
  *
  * This software is licensed as described in the file COPYING, which
  * you should have received as part of this distribution. The terms
@@ -116,8 +116,8 @@ CURLcode Curl_none_md5sum(unsigned char *input, size_t inputlen,
 #define MD5_DIGEST_LENGTH 16 /* fixed size */
 #endif
 
-#ifndef SHA256_DIGEST_LENGTH
-#define SHA256_DIGEST_LENGTH 32 /* fixed size */
+#ifndef CURL_SHA256_DIGEST_LENGTH
+#define CURL_SHA256_DIGEST_LENGTH 32 /* fixed size */
 #endif
 
 /* see https://tools.ietf.org/html/draft-ietf-tls-applayerprotoneg-04 */