diff --git a/configure.ac b/configure.ac
index ab3d2888..951b5ab3 100644
--- a/configure.ac
+++ b/configure.ac
@@ -493,25 +493,20 @@ if test "x$have_appletls" = "xyes"; then
   use_md="apple"
   AC_DEFINE([USE_APPLE_MD], [1], [What message digest implementation to use])
 else
-  if test "x$have_wintls" = "xyes"; then
-    use_md="windows"
-    AC_DEFINE([USE_WINDOWS_MD], [1], [What message digest implementation to use])
+  if test "x$have_libnettle" = "xyes"; then
+    AC_DEFINE([USE_LIBNETTLE_MD], [1], [What message digest implementation to use])
+    use_md="libnettle"
   else
-    if test "x$have_libnettle" = "xyes"; then
-      AC_DEFINE([USE_LIBNETTLE_MD], [1], [What message digest implementation to use])
-      use_md="libnettle"
+    if test "x$have_libgcrypt" = "xyes"; then
+      AC_DEFINE([USE_LIBGCRYPT_MD], [1], [What message digest implementation to use])
+      use_md="libgcrypt"
     else
-      if test "x$have_libgcrypt" = "xyes"; then
-        AC_DEFINE([USE_LIBGCRYPT_MD], [1], [What message digest implementation to use])
-        use_md="libgcrypt"
+      if test "x$have_openssl" = "xyes"; then
+        AC_DEFINE([USE_OPENSSL_MD], [1], [What message digest implementation to use])
+        use_md="openssl"
       else
-        if test "x$have_openssl" = "xyes"; then
-          AC_DEFINE([USE_OPENSSL_MD], [1], [What message digest implementation to use])
-          use_md="openssl"
-        else
-          AC_DEFINE([USE_INTERNAL_MD], [1], [What message digest implementation to use])
-          use_md="internal"
-        fi
+        AC_DEFINE([USE_INTERNAL_MD], [1], [What message digest implementation to use])
+        use_md="internal"
       fi
     fi
   fi
diff --git a/src/Makefile.am b/src/Makefile.am
index aa4abca7..89e442e7 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -348,10 +348,6 @@ SRCS += \
 	AppleTLSSession.cc AppleTLSSession.h
 endif # HAVE_APPLETLS
 
-if USE_WINDOWS_MD
-SRCS += WinMessageDigestImpl.cc
-endif # USE_WINDOWS_MD
-
 if HAVE_WINTLS
 SRCS += \
 	WinTLSContext.cc WinTLSContext.h \
diff --git a/src/WinMessageDigestImpl.cc b/src/WinMessageDigestImpl.cc
deleted file mode 100644
index 28407f4c..00000000
--- a/src/WinMessageDigestImpl.cc
+++ /dev/null
@@ -1,193 +0,0 @@
-/* <!-- copyright */
-/*
- * aria2 - The high speed download utility
- *
- * Copyright (C) 2013 Nils Maier
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
- *
- * In addition, as a special exception, the copyright holders give
- * permission to link the code of portions of this program with the
- * OpenSSL library under certain conditions as described in each
- * individual source file, and distribute linked combinations
- * including the two.
- * You must obey the GNU General Public License in all respects
- * for all of the code used other than OpenSSL.  If you modify
- * file(s) with this exception, you may extend this exception to your
- * version of the file(s), but you are not obligated to do so.  If you
- * do not wish to do so, delete this exception statement from your
- * version.  If you delete this exception statement from all source
- * files in the program, then also delete it here.
- */
-/* copyright --> */
-
-#include "MessageDigestImpl.h"
-
-#include <wincrypt.h>
-
-#include "fmt.h"
-#include "DlAbortEx.h"
-#include "LogFactory.h"
-
-namespace {
-using namespace aria2;
-
-class Context {
-private:
-  HCRYPTPROV provider_;
-public:
-  Context() {
-    if (!::CryptAcquireContext(&provider_, nullptr, nullptr,
-                               PROV_RSA_AES, CRYPT_VERIFYCONTEXT)) {
-      if (!::CryptAcquireContext(&provider_, nullptr, nullptr, PROV_RSA_AES,
-                                CRYPT_VERIFYCONTEXT)) {
-        throw DL_ABORT_EX("Failed to get cryptographic provider");
-      }
-    }
-  }
-  ~Context() {
-    ::CryptReleaseContext(provider_, 0);
-  }
-
-  HCRYPTPROV get() {
-    return provider_;
-  }
-};
-
-// XXX static OK?
-static Context context_;
-
-inline size_t getAlgLength(ALG_ID id)
-{
-  Context context;
-  HCRYPTHASH hash;
-  if (!::CryptCreateHash(context.get(), id, 0, 0, &hash)) {
-    throw DL_ABORT_EX(fmt("Failed to initialize hash %d", id));
-  }
-
-  DWORD rv = 0;
-  DWORD len = sizeof(rv);
-  if (!::CryptGetHashParam(hash, HP_HASHSIZE, reinterpret_cast<BYTE*>(&rv),
-                            &len, 0)) {
-    throw DL_ABORT_EX("Failed to initialize hash(2)");
-  }
-  ::CryptDestroyHash(hash);
-
-  return rv;
-}
-
-} // namespace
-
-namespace aria2 {
-
-
-template<ALG_ID id>
-class MessageDigestBase : public MessageDigestImpl {
-private:
-  HCRYPTHASH hash_;
-  DWORD len_;
-
-  void destroy() {
-    if (hash_) {
-      ::CryptDestroyHash(hash_);
-      hash_ = 0;
-    }
-  }
-
-public:
-  MessageDigestBase() : hash_(0), len_(0) { reset(); }
-  virtual ~MessageDigestBase() { destroy(); }
-
-  static size_t length() {
-    MessageDigestBase<id> rv;
-    return rv.getDigestLength();
-  }
-  virtual size_t getDigestLength() const CXX11_OVERRIDE {
-    return len_;
-  }
-  virtual void reset() CXX11_OVERRIDE {
-    destroy();
-    if (!::CryptCreateHash(context_.get(), id, 0, 0, &hash_)) {
-      throw DL_ABORT_EX("Failed to create hash");
-    }
-    DWORD len = sizeof(len_);
-    if (!::CryptGetHashParam(hash_, HP_HASHSIZE, reinterpret_cast<BYTE*>(&len_),
-                             &len, 0)) {
-      throw DL_ABORT_EX("Failed to initialize hash");
-    }
-  }
-  virtual void update(const void* data, size_t length) CXX11_OVERRIDE {
-    auto bytes = reinterpret_cast<const unsigned char*>(data);
-    while (length) {
-      DWORD l = std::min(length, (size_t)std::numeric_limits<uint32_t>::max());
-      if (!::CryptHashData(hash_, bytes, l, 0)) {
-        throw DL_ABORT_EX("Failed to update hash");
-      }
-      length -= l;
-      bytes += l;
-    }
-  }
-  virtual void digest(unsigned char* md) CXX11_OVERRIDE {
-    DWORD len = len_;
-    if (!::CryptGetHashParam(hash_, HP_HASHVAL, md, &len, 0)) {
-      throw DL_ABORT_EX("Failed to create hash digest");
-    }
-  }
-};
-
-typedef MessageDigestBase<CALG_MD5> MessageDigestMD5;
-typedef MessageDigestBase<CALG_SHA1> MessageDigestSHA1;
-typedef MessageDigestBase<CALG_SHA_256> MessageDigestSHA256;
-typedef MessageDigestBase<CALG_SHA_384> MessageDigestSHA384;
-typedef MessageDigestBase<CALG_SHA_512> MessageDigestSHA512;
-
-std::unique_ptr<MessageDigestImpl> MessageDigestImpl::sha1()
-{
-  return std::unique_ptr<MessageDigestImpl>(new MessageDigestSHA1());
-}
-
-namespace {
-MessageDigestImpl::hashes_t initialize() {
-  MessageDigestImpl::hashes_t rv = {
-    { "sha-1", MessageDigestImpl::make_hi<MessageDigestSHA1>() },
-    { "md5", MessageDigestImpl::make_hi<MessageDigestMD5>() },
-  };
-
-  try {
-    rv.insert({ "sha-256", MessageDigestImpl::make_hi<MessageDigestSHA256>() });
-  }
-  catch (RecoverableException &ex) {
-    printf("SHA-256 is not supported on this machine");
-  }
-  try {
-    rv.insert({ "sha-384", MessageDigestImpl::make_hi<MessageDigestSHA384>() });
-  }
-  catch (RecoverableException &ex) {
-    printf("SHA-384 is not supported on this machine");
-  }
-  try {
-    rv.insert({ "sha-512", MessageDigestImpl::make_hi<MessageDigestSHA512>() });
-  }
-  catch (RecoverableException &ex) {
-    printf("SHA-512 is not supported on this machine");
-  }
-
-  return rv;
-};
-} // namespace
-
-MessageDigestImpl::hashes_t MessageDigestImpl::hashes = initialize();
-
-} // namespace aria2