Remove ENABLE_MESSAGE_DIGEST, since we got the internal md, always

40 files changed, 45 insertions, 292 deletions

diff --git a/src/AbstractCommand.cc b/src/AbstractCommand.cc
index 5dad881a..313155ba 100644
--- a/src/AbstractCommand.cc
+++ b/src/AbstractCommand.cc
@@ -66,13 +66,11 @@
 #include "FileEntry.h"
 #include "error_code.h"
 #include "SocketRecvBuffer.h"
+#include "ChecksumCheckIntegrityEntry.h"
 #ifdef ENABLE_ASYNC_DNS
 #include "AsyncNameResolver.h"
 #include "AsyncNameResolverMan.h"
 #endif // ENABLE_ASYNC_DNS
-#ifdef ENABLE_MESSAGE_DIGEST
-# include "ChecksumCheckIntegrityEntry.h"
-#endif // ENABLE_MESSAGE_DIGEST
 
 namespace aria2 {
 
diff --git a/src/ConsoleStatCalc.cc b/src/ConsoleStatCalc.cc
index f57b1dbb..64ae3e30 100644
--- a/src/ConsoleStatCalc.cc
+++ b/src/ConsoleStatCalc.cc
@@ -359,7 +359,6 @@ ConsoleStatCalc::calculateStat(const DownloadEngine* e)
       }
     }
   }
-#ifdef ENABLE_MESSAGE_DIGEST
   {
     auto& entry = e->getCheckIntegrityMan()->getPickedEntry();
     if(entry) {
@@ -378,7 +377,6 @@ ConsoleStatCalc::calculateStat(const DownloadEngine* e)
       }
     }
   }
-#endif // ENABLE_MESSAGE_DIGEST
   if(isTTY_) {
     if (truncate_) {
       auto str = o.str(color, cols);
diff --git a/src/Context.cc b/src/Context.cc
index 080c0c88..25182c47 100644
--- a/src/Context.cc
+++ b/src/Context.cc
@@ -66,6 +66,7 @@
 #include "fmt.h"
 #include "console.h"
 #include "UriListParser.h"
+#include "message_digest_helper.h"
 #ifdef ENABLE_BITTORRENT
 # include "bittorrent_helper.h"
 #endif // ENABLE_BITTORRENT
@@ -73,9 +74,6 @@
 # include "metalink_helper.h"
 # include "MetalinkEntry.h"
 #endif // ENABLE_METALINK
-#ifdef ENABLE_MESSAGE_DIGEST
-# include "message_digest_helper.h"
-#endif // ENABLE_MESSAGE_DIGEST
 
 extern char* optarg;
 extern int optind, opterr, optopt;
diff --git a/src/DefaultBtProgressInfoFile.cc b/src/DefaultBtProgressInfoFile.cc
index ed5fd8f8..b1e4fd14 100644
--- a/src/DefaultBtProgressInfoFile.cc
+++ b/src/DefaultBtProgressInfoFile.cc
@@ -347,13 +347,8 @@ void DefaultBtProgressInfoFile::load()
         ((size_t)bitfieldLength);
       READ_CHECK(fp, pieceBitfield.get(), bitfieldLength);
       piece->setBitfield(pieceBitfield.get(), bitfieldLength);
-
-#ifdef ENABLE_MESSAGE_DIGEST
-
       piece->setHashType(dctx_->getPieceHashType());
 
-#endif // ENABLE_MESSAGE_DIGEST
-
       inFlightPieces.push_back(piece);
     }
     pieceStorage_->addInFlightPiece(inFlightPieces);
diff --git a/src/DefaultPieceStorage.cc b/src/DefaultPieceStorage.cc
index 68dc63b7..c7fd7aa9 100644
--- a/src/DefaultPieceStorage.cc
+++ b/src/DefaultPieceStorage.cc
@@ -113,12 +113,8 @@ std::shared_ptr<Piece> DefaultPieceStorage::checkOutPiece
   std::shared_ptr<Piece> piece = findUsedPiece(index);
   if(!piece) {
     piece.reset(new Piece(index, bitfieldMan_->getBlockLength(index)));
-#ifdef ENABLE_MESSAGE_DIGEST
-
     piece->setHashType(downloadContext_->getPieceHashType());
 
-#endif // ENABLE_MESSAGE_DIGEST
-
     addUsedPiece(piece);
   }
   piece->addUser(cuid);
@@ -780,12 +776,8 @@ void DefaultPieceStorage::markPiecesDone(int64_t length)
         p->completeBlock(i);
       }
 
-#ifdef ENABLE_MESSAGE_DIGEST
-
       p->setHashType(downloadContext_->getPieceHashType());
 
-#endif // ENABLE_MESSAGE_DIGEST
-
       addUsedPiece(p);
     }
   }
diff --git a/src/DownloadCommand.cc b/src/DownloadCommand.cc
index 0e5104d1..e42339bc 100644
--- a/src/DownloadCommand.cc
+++ b/src/DownloadCommand.cc
@@ -65,10 +65,8 @@
 #include "Piece.h"
 #include "WrDiskCacheEntry.h"
 #include "DownloadFailureException.h"
-#ifdef ENABLE_MESSAGE_DIGEST
-# include "MessageDigest.h"
-# include "message_digest_helper.h"
-#endif // ENABLE_MESSAGE_DIGEST
+#include "MessageDigest.h"
+#include "message_digest_helper.h"
 #ifdef ENABLE_BITTORRENT
 # include "bittorrent_helper.h"
 #endif // ENABLE_BITTORRENT
@@ -86,7 +84,6 @@ DownloadCommand::DownloadCommand(cuid_t cuid,
     lowestDownloadSpeedLimit_(0),
     pieceHashValidationEnabled_(false)
 {
-#ifdef ENABLE_MESSAGE_DIGEST
   {
     if(getOption()->getAsBool(PREF_REALTIME_CHUNK_CHECKSUM)) {
       const std::string& algo = getDownloadContext()->getPieceHashType();
@@ -96,7 +93,6 @@ DownloadCommand::DownloadCommand(cuid_t cuid,
       }
     }
   }
-#endif // ENABLE_MESSAGE_DIGEST
 
   peerStat_ = req->initPeerStat();
   peerStat_->downloadStart();
@@ -236,8 +232,6 @@ bool DownloadCommand::executeInternal() {
       A2_LOG_INFO(fmt(MSG_SEGMENT_DOWNLOAD_COMPLETED,
                       getCuid()));
 
-#ifdef ENABLE_MESSAGE_DIGEST
-
       {
         const std::string& expectedPieceHash =
           getDownloadContext()->getPieceHash(segment->getIndex());
@@ -270,9 +264,6 @@ bool DownloadCommand::executeInternal() {
         }
       }
 
-#else // !ENABLE_MESSAGE_DIGEST
-      completeSegment(getCuid(), segment);
-#endif // !ENABLE_MESSAGE_DIGEST
     } else {
       // If segment is not canceled here, in the next pipelining
       // request, aria2 requests bad range
@@ -319,7 +310,6 @@ bool DownloadCommand::prepareForNextSegment() {
         getFileEntry()->setLength(getPieceStorage()->getCompletedLength());
       }
     }
-#ifdef ENABLE_MESSAGE_DIGEST
     if(getDownloadContext()->getPieceHashType().empty()) {
       auto entry = make_unique<ChecksumCheckIntegrityEntry>(getRequestGroup());
       if(entry->isValidationReady()) {
@@ -329,7 +319,6 @@ bool DownloadCommand::prepareForNextSegment() {
           (std::move(entry));
       }
     }
-#endif // ENABLE_MESSAGE_DIGEST
     // Following 2lines are needed for DownloadEngine to detect
     // completed RequestGroups without 1sec delay.
     getDownloadEngine()->setNoWait(true);
@@ -370,8 +359,6 @@ bool DownloadCommand::prepareForNextSegment() {
   }
 }
 
-#ifdef ENABLE_MESSAGE_DIGEST
-
 void DownloadCommand::validatePieceHash(const std::shared_ptr<Segment>& segment,
                                         const std::string& expectedHash,
                                         const std::string& actualHash)
@@ -393,8 +380,6 @@ void DownloadCommand::validatePieceHash(const std::shared_ptr<Segment>& segment,
   }
 }
 
-#endif // ENABLE_MESSAGE_DIGEST
-
 void DownloadCommand::completeSegment(cuid_t cuid,
                                       const std::shared_ptr<Segment>& segment)
 {
diff --git a/src/DownloadCommand.h b/src/DownloadCommand.h
index ddb87da1..3efaf5a0 100644
--- a/src/DownloadCommand.h
+++ b/src/DownloadCommand.h
@@ -43,9 +43,7 @@ namespace aria2 {
 
 class PeerStat;
 class StreamFilter;
-#ifdef ENABLE_MESSAGE_DIGEST
 class MessageDigest;
-#endif // ENABLE_MESSAGE_DIGEST
 
 class DownloadCommand : public AbstractCommand {
 private:
@@ -53,9 +51,7 @@ private:
 
   std::unique_ptr<StreamFilter> streamFilter_;
 
-#ifdef ENABLE_MESSAGE_DIGEST
   std::unique_ptr<MessageDigest> messageDigest_;
-#endif // ENABLE_MESSAGE_DIGEST
 
   time_t startupIdleTime_;
 
diff --git a/src/DownloadEngineFactory.cc b/src/DownloadEngineFactory.cc
index 39b04f98..fa350589 100644
--- a/src/DownloadEngineFactory.cc
+++ b/src/DownloadEngineFactory.cc
@@ -43,9 +43,7 @@
 #include "FileAllocationMan.h"
 #include "CheckIntegrityMan.h"
 #include "CheckIntegrityEntry.h"
-#ifdef ENABLE_MESSAGE_DIGEST
-# include "CheckIntegrityDispatcherCommand.h"
-#endif // ENABLE_MESSAGE_DIGEST
+#include "CheckIntegrityDispatcherCommand.h"
 #include "prefs.h"
 #include "FillRequestGroupCommand.h"
 #include "FileAllocationDispatcherCommand.h"
@@ -157,19 +155,15 @@ DownloadEngineFactory::newDownloadEngine
     e->setRequestGroupMan(std::move(requestGroupMan));
   }
   e->setFileAllocationMan(make_unique<FileAllocationMan>());
-#ifdef ENABLE_MESSAGE_DIGEST
   e->setCheckIntegrityMan(make_unique<CheckIntegrityMan>());
-#endif // ENABLE_MESSAGE_DIGEST
   e->addRoutineCommand(make_unique<FillRequestGroupCommand>
                        (e->newCUID(), e.get()));
   e->addRoutineCommand(make_unique<FileAllocationDispatcherCommand>
                        (e->newCUID(), e->getFileAllocationMan().get(),
                         e.get()));
-#ifdef ENABLE_MESSAGE_DIGEST
   e->addRoutineCommand(make_unique<CheckIntegrityDispatcherCommand>
                        (e->newCUID(), e->getCheckIntegrityMan().get(),
                         e.get()));
-#endif // ENABLE_MESSAGE_DIGEST
 
   if(op->getAsInt(PREF_AUTO_SAVE_INTERVAL) > 0) {
     e->addRoutineCommand
diff --git a/src/FeatureConfig.cc b/src/FeatureConfig.cc
index d1063a2a..74dafd2b 100644
--- a/src/FeatureConfig.cc
+++ b/src/FeatureConfig.cc
@@ -141,11 +141,7 @@ const char* strSupportedFeature(int feature)
     break;
 
   case(FEATURE_MESSAGE_DIGEST):
-#ifdef ENABLE_MESSAGE_DIGEST
     return "Message Digest";
-#else // !ENABLE_MESSAGE_DIGEST
-    return 0;
-#endif // !ENABLE_MESSAGE_DIGEST
     break;
 
   case(FEATURE_METALINK):
diff --git a/src/FtpNegotiationCommand.cc b/src/FtpNegotiationCommand.cc
index fd369370..16237fe0 100644
--- a/src/FtpNegotiationCommand.cc
+++ b/src/FtpNegotiationCommand.cc
@@ -75,9 +75,7 @@
 #include "error_code.h"
 #include "SocketRecvBuffer.h"
 #include "NullProgressInfoFile.h"
-#ifdef ENABLE_MESSAGE_DIGEST
-# include "ChecksumCheckIntegrityEntry.h"
-#endif // ENABLE_MESSAGE_DIGEST
+#include "ChecksumCheckIntegrityEntry.h"
 
 namespace aria2 {
 
@@ -386,7 +384,6 @@ bool FtpNegotiationCommand::onFileSizeDetermined(int64_t totalLength)
 
     if(getDownloadContext()->knowsTotalLength() &&
        getRequestGroup()->downloadFinishedByFileLength()) {
-#ifdef ENABLE_MESSAGE_DIGEST
       // TODO Known issue: if .aria2 file exists, it will not be
       // deleted on successful verification, because .aria2 file is
       // not loaded.  See also
@@ -401,9 +398,8 @@ bool FtpNegotiationCommand::onFileSizeDetermined(int64_t totalLength)
         getDownloadEngine()->getCheckIntegrityMan()->pushEntry
           (std::move(entry));
         sequence_ = SEQ_EXIT;
-      } else
-#endif // ENABLE_MESSAGE_DIGEST
-        {
+      }
+      else {
           getPieceStorage()->markAllPiecesDone();
           getDownloadContext()->setChecksumVerified(true);
           sequence_ = SEQ_DOWNLOAD_ALREADY_COMPLETED;
@@ -423,7 +419,6 @@ bool FtpNegotiationCommand::onFileSizeDetermined(int64_t totalLength)
 
     if(getDownloadContext()->knowsTotalLength()) {
       A2_LOG_DEBUG("File length becomes zero and it means download completed.");
-#ifdef ENABLE_MESSAGE_DIGEST
       // TODO Known issue: if .aria2 file exists, it will not be
       // deleted on successful verification, because .aria2 file is
       // not loaded.  See also
@@ -437,7 +432,6 @@ bool FtpNegotiationCommand::onFileSizeDetermined(int64_t totalLength)
           (std::move(entry));
         sequence_ = SEQ_EXIT;
       } else
-#endif // ENABLE_MESSAGE_DIGEST
         {
           sequence_ = SEQ_DOWNLOAD_ALREADY_COMPLETED;
           getPieceStorage()->markAllPiecesDone();
diff --git a/src/GrowSegment.cc b/src/GrowSegment.cc
index bb5d1e54..433813df 100644
--- a/src/GrowSegment.cc
+++ b/src/GrowSegment.cc
@@ -50,15 +50,11 @@ void GrowSegment::updateWrittenLength(int32_t bytes)
   piece_->setAllBlock();
 }
 
-#ifdef ENABLE_MESSAGE_DIGEST
-
 std::string GrowSegment::getDigest()
 {
   return A2STR::NIL;
 }
 
-#endif // ENABLE_MESSAGE_DIGEST
-
 void GrowSegment::clear(WrDiskCache* diskCache)
 {
   writtenLength_ = 0;
diff --git a/src/GrowSegment.h b/src/GrowSegment.h
index 8ca96af7..70aed4c0 100644
--- a/src/GrowSegment.h
+++ b/src/GrowSegment.h
@@ -85,8 +85,6 @@ public:
 
   virtual void updateWrittenLength(int32_t bytes) CXX11_OVERRIDE;
 
-#ifdef ENABLE_MESSAGE_DIGEST
-
   virtual bool updateHash
   (int32_t begin,
    const unsigned char* data,
@@ -102,8 +100,6 @@ public:
 
   virtual std::string getDigest() CXX11_OVERRIDE;
 
-#endif // ENABLE_MESSAGE_DIGEST
-
   virtual void clear(WrDiskCache* diskCache) CXX11_OVERRIDE;
 
   virtual std::shared_ptr<Piece> getPiece() const CXX11_OVERRIDE;
diff --git a/src/HttpResponse.cc b/src/HttpResponse.cc
index dae61dc3..c4168b3e 100644
--- a/src/HttpResponse.cc
+++ b/src/HttpResponse.cc
@@ -59,9 +59,7 @@
 #include "MetalinkHttpEntry.h"
 #include "base64.h"
 #include "array_fun.h"
-#ifdef ENABLE_MESSAGE_DIGEST
 #include "MessageDigest.h"
-#endif // ENABLE_MESSAGE_DIGEST
 #ifdef HAVE_ZLIB
 # include "GZipDecodingStreamFilter.h"
 #endif // HAVE_ZLIB
@@ -395,7 +393,6 @@ void HttpResponse::getMetalinKHttpEntries(
   std::sort(result.begin(), result.end());
 }
 
-#ifdef ENABLE_MESSAGE_DIGEST
 // Digest header field is defined by
 // http://tools.ietf.org/html/rfc3230.
 void HttpResponse::getDigest(std::vector<Checksum>& result) const
@@ -445,6 +442,5 @@ void HttpResponse::getDigest(std::vector<Checksum>& result) const
   }
   std::swap(temp, result);
 }
-#endif // ENABLE_MESSAGE_DIGEST
 
 } // namespace aria2
diff --git a/src/HttpResponse.h b/src/HttpResponse.h
index fabb6f7d..2e7b964a 100644
--- a/src/HttpResponse.h
+++ b/src/HttpResponse.h
@@ -125,13 +125,11 @@ public:
   void getMetalinKHttpEntries(std::vector<MetalinkHttpEntry>& result,
                               const std::shared_ptr<Option>& option) const;
 
-#ifdef ENABLE_MESSAGE_DIGEST
   // Returns all digests specified in Digest header field.  Sort
   // strong algorithm first. Strength is defined in MessageDigest. If
   // several same digest algorithms are available, but they have
   // different value, they are all ignored.
   void getDigest(std::vector<Checksum>& result) const;
-#endif // ENABLE_MESSAGE_DIGEST
 
 };
 
diff --git a/src/HttpResponseCommand.cc b/src/HttpResponseCommand.cc
index d6dbd7a9..7c44991a 100644
--- a/src/HttpResponseCommand.cc
+++ b/src/HttpResponseCommand.cc
@@ -75,10 +75,8 @@
 #include "SocketRecvBuffer.h"
 #include "MetalinkHttpEntry.h"
 #include "NullProgressInfoFile.h"
-#ifdef ENABLE_MESSAGE_DIGEST
-# include "Checksum.h"
-# include "ChecksumCheckIntegrityEntry.h"
-#endif // ENABLE_MESSAGE_DIGEST
+#include "Checksum.h"
+#include "ChecksumCheckIntegrityEntry.h"
 #ifdef HAVE_ZLIB
 # include "GZipDecodingStreamFilter.h"
 #endif // HAVE_ZLIB
@@ -210,7 +208,6 @@ bool HttpResponseCommand::executeInternal()
       }
     }
 
-#ifdef ENABLE_MESSAGE_DIGEST
     if (httpHeader->defined(HttpHeader::DIGEST)) {
       std::vector<Checksum> checksums;
       httpResponse->getDigest(checksums);
@@ -228,7 +225,6 @@ bool HttpResponseCommand::executeInternal()
         }
       }
     }
-#endif // ENABLE_MESSAGE_DIGEST
   }
 
   if(statusCode >= 300) {
@@ -280,7 +276,6 @@ bool HttpResponseCommand::executeInternal()
     return handleDefaultEncoding(std::move(httpResponse));
   }
 
-#ifdef ENABLE_MESSAGE_DIGEST
   if (!ctx->getHashType().empty() && httpHeader->defined(HttpHeader::DIGEST)) {
     std::vector<Checksum> checksums;
     httpResponse->getDigest(checksums);
@@ -290,7 +285,6 @@ bool HttpResponseCommand::executeInternal()
       }
     }
   }
-#endif // ENABLE_MESSAGE_DIGEST
 
   // validate totalsize
   grp->validateTotalLength(fe->getLength(), httpResponse->getEntityLength());
@@ -424,7 +418,6 @@ bool HttpResponseCommand::handleOtherEncoding(
       getRequestGroup()->downloadFinishedByFileLength()) {
     getRequestGroup()->initPieceStorage();
 
-#ifdef ENABLE_MESSAGE_DIGEST
     // TODO Known issue: if .aria2 file exists, it will not be deleted
     // on successful verification, because .aria2 file is not loaded.
     // See also FtpNegotiationCommand::onFileSizeDetermined()
@@ -434,9 +427,8 @@ bool HttpResponseCommand::handleOtherEncoding(
       entry->initValidator();
       getPieceStorage()->getDiskAdaptor()->openExistingFile();
       getDownloadEngine()->getCheckIntegrityMan()->pushEntry(std::move(entry));
-    } else
-#endif // ENABLE_MESSAGE_DIGEST
-    {
+    }
+    else {
       getPieceStorage()->markAllPiecesDone();
       getDownloadContext()->setChecksumVerified(true);
       A2_LOG_NOTICE(fmt(MSG_DOWNLOAD_ALREADY_COMPLETED,
@@ -459,14 +451,12 @@ bool HttpResponseCommand::handleOtherEncoding(
     // TODO Known issue: if .aria2 file exists, it will not be deleted
     // on successful verification, because .aria2 file is not loaded.
     // See also FtpNegotiationCommand::onFileSizeDetermined()
-#ifdef ENABLE_MESSAGE_DIGEST
     if (getDownloadContext()->isChecksumVerificationNeeded()) {
       A2_LOG_DEBUG("Verify checksum for zero-length file");
       auto entry = make_unique<ChecksumCheckIntegrityEntry>(getRequestGroup());
       entry->initValidator();
       getDownloadEngine()->getCheckIntegrityMan()->pushEntry(std::move(entry));
     } else
-#endif // ENABLE_MESSAGE_DIGEST
     {
       getRequestGroup()->getPieceStorage()->markAllPiecesDone();
     }
@@ -572,7 +562,6 @@ void HttpResponseCommand::onDryRunFileFound()
   poolConnection();
 }
 
-#ifdef ENABLE_MESSAGE_DIGEST
 bool HttpResponseCommand::checkChecksum(
     const std::shared_ptr<DownloadContext>& dctx, const Checksum& checksum)
 {
@@ -586,6 +575,5 @@ bool HttpResponseCommand::checkChecksum(
 
   return false;
 }
-#endif // ENABLE_MESSAGE_DIGEST
 
 } // namespace aria2
diff --git a/src/HttpResponseCommand.h b/src/HttpResponseCommand.h
index bd66eae1..7cb367e1 100644
--- a/src/HttpResponseCommand.h
+++ b/src/HttpResponseCommand.h
@@ -45,9 +45,7 @@ class HttpDownloadCommand;
 class HttpResponse;
 class SocketCore;
 class StreamFilter;
-#ifdef ENABLE_MESSAGE_DIGEST
 class Checksum;
-#endif // ENABLE_MESSAGE_DIGEST
 
 // HttpResponseCommand receives HTTP response header from remote
 // server.  Because network I/O is non-blocking, execute() returns
@@ -76,13 +74,11 @@ private:
   void poolConnection();
 
   void onDryRunFileFound();
-#ifdef ENABLE_MESSAGE_DIGEST
   // Returns true if dctx and checksum has same hash type and hash
   // value.  If they have same hash type but different hash value,
   // throws exception.  Otherwise returns false.
   bool checkChecksum(const std::shared_ptr<DownloadContext>& dctx,
                      const Checksum& checksum);
-#endif // ENABLE_MESSAGE_DIGEST
 
 protected:
   bool executeInternal() CXX11_OVERRIDE;
diff --git a/src/HttpServerCommand.cc b/src/HttpServerCommand.cc
index 096b3d1f..4a4d6d61 100644
--- a/src/HttpServerCommand.cc
+++ b/src/HttpServerCommand.cc
@@ -51,10 +51,8 @@
 #include "fmt.h"
 #include "SocketRecvBuffer.h"
 #include "base64.h"
-#ifdef ENABLE_MESSAGE_DIGEST
-#  include "MessageDigest.h"
-#  include "message_digest_helper.h"
-#endif // ENABLE_MESSAGE_DIGEST
+#include "MessageDigest.h"
+#include "message_digest_helper.h"
 #ifdef ENABLE_WEBSOCKET
 #  include "WebSocketResponseCommand.h"
 #endif // ENABLE_WEBSOCKET
diff --git a/src/Makefile.am b/src/Makefile.am
index 0daa5c01..4046715a 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -251,7 +251,18 @@ SRCS =  option_processing.cc\
 	HttpProxyRequestConnectChain.h\
 	FtpNegotiationConnectChain.h\
 	FtpTunnelRequestConnectChain.h\
-	Lock.h
+	Lock.h \
+	IteratableChunkChecksumValidator.cc IteratableChunkChecksumValidator.h\
+	IteratableChecksumValidator.cc IteratableChecksumValidator.h\
+	CheckIntegrityDispatcherCommand.cc CheckIntegrityDispatcherCommand.h\
+	CheckIntegrityCommand.cc CheckIntegrityCommand.h\
+	ChecksumCheckIntegrityEntry.cc ChecksumCheckIntegrityEntry.h\
+	message_digest_helper.cc message_digest_helper.h\
+	Checksum.cc Checksum.h\
+	ChunkChecksum.cc ChunkChecksum.h\
+	MessageDigest.cc MessageDigest.h\
+	MessageDigestImpl.h\
+	HashFuncEntry.h
 
 if ANDROID
 SRCS += android/android.c
@@ -403,20 +414,6 @@ SRCS += AsyncNameResolver.cc AsyncNameResolver.h\
 	AsyncNameResolverMan.cc AsyncNameResolverMan.h
 endif # ENABLE_ASYNC_DNS
 
-if ENABLE_MESSAGE_DIGEST
-SRCS += IteratableChunkChecksumValidator.cc IteratableChunkChecksumValidator.h\
-	IteratableChecksumValidator.cc IteratableChecksumValidator.h\
-	CheckIntegrityDispatcherCommand.cc CheckIntegrityDispatcherCommand.h\
-	CheckIntegrityCommand.cc CheckIntegrityCommand.h\
-	ChecksumCheckIntegrityEntry.cc ChecksumCheckIntegrityEntry.h\
-	message_digest_helper.cc message_digest_helper.h\
-	Checksum.cc Checksum.h\
-	ChunkChecksum.cc ChunkChecksum.h\
-	MessageDigest.cc MessageDigest.h\
-	MessageDigestImpl.h\
-	HashFuncEntry.h
-endif # ENABLE_MESSAGE_DIGEST
-
 if ENABLE_BITTORRENT
 SRCS += PeerAbstractCommand.cc PeerAbstractCommand.h\
 	PeerInitiateConnectionCommand.cc PeerInitiateConnectionCommand.h\
diff --git a/src/Metalink2RequestGroup.cc b/src/Metalink2RequestGroup.cc
index 5daa6bdc..6463aae6 100644
--- a/src/Metalink2RequestGroup.cc
+++ b/src/Metalink2RequestGroup.cc
@@ -64,10 +64,8 @@
 # include "BtDependency.h"
 # include "download_helper.h"
 #endif // ENABLE_BITTORRENT
-#ifdef ENABLE_MESSAGE_DIGEST
-# include "Checksum.h"
-# include "ChunkChecksum.h"
-#endif // ENABLE_MESSAGE_DIGEST
+#include "Checksum.h"
+#include "ChunkChecksum.h"
 
 namespace aria2 {
 
@@ -255,15 +253,11 @@ Metalink2RequestGroup::createRequestGroup
       // If piece hash is specified in the metalink,
       // make segment size equal to piece hash size.
       int32_t pieceLength;
-#ifdef ENABLE_MESSAGE_DIGEST
       if(!entry->chunkChecksum) {
         pieceLength = option->getAsInt(PREF_PIECE_LENGTH);
       } else {
         pieceLength = entry->chunkChecksum->getPieceLength();
       }
-#else
-      pieceLength = option->getAsInt(PREF_PIECE_LENGTH);
-#endif // ENABLE_MESSAGE_DIGEST
       dctx = std::make_shared<DownloadContext>
         (pieceLength,
          entry->getLength(),
@@ -274,7 +268,6 @@ Metalink2RequestGroup::createRequestGroup
       if(option->getAsBool(PREF_METALINK_ENABLE_UNIQUE_PROTOCOL)) {
         dctx->getFirstFileEntry()->setUniqueProtocol(true);
       }
-#ifdef ENABLE_MESSAGE_DIGEST
       if(entry->checksum) {
         dctx->setDigest(entry->checksum->getHashType(),
                         entry->checksum->getDigest());
@@ -285,7 +278,6 @@ Metalink2RequestGroup::createRequestGroup
            std::begin(entry->chunkChecksum->getPieceHashes()),
            std::end(entry->chunkChecksum->getPieceHashes()));
       }
-#endif // ENABLE_MESSAGE_DIGEST
       dctx->setSignature(entry->popSignature());
       rg->setNumConcurrentCommand
         (entry->maxConnections < 0 ?
diff --git a/src/MetalinkEntry.cc b/src/MetalinkEntry.cc
index 8decf8c2..6961a910 100644
--- a/src/MetalinkEntry.cc
+++ b/src/MetalinkEntry.cc
@@ -41,10 +41,8 @@
 #include "FileEntry.h"
 #include "util.h"
 #include "a2functional.h"
-#ifdef ENABLE_MESSAGE_DIGEST
-# include "Checksum.h"
-# include "ChunkChecksum.h"
-#endif // ENABLE_MESSAGE_DIGEST
+#include "Checksum.h"
+#include "ChunkChecksum.h"
 #include "Signature.h"
 #include "SimpleRandomizer.h"
 
diff --git a/src/MetalinkEntry.h b/src/MetalinkEntry.h
index 8884ee7f..699dda88 100644
--- a/src/MetalinkEntry.h
+++ b/src/MetalinkEntry.h
@@ -46,10 +46,8 @@ namespace aria2 {
 class MetalinkResource;
 class MetalinkMetaurl;
 class FileEntry;
-#ifdef ENABLE_MESSAGE_DIGEST
 class Checksum;
 class ChunkChecksum;
-#endif // ENABLE_MESSAGE_DIGEST
 class Signature;
 
 class MetalinkEntry {
@@ -63,10 +61,9 @@ public:
   std::vector<std::unique_ptr<MetalinkResource>> resources;
   std::vector<std::unique_ptr<MetalinkMetaurl>> metaurls;
   int maxConnections; // Metalink3Spec
-#ifdef ENABLE_MESSAGE_DIGEST
   std::unique_ptr<Checksum> checksum;
   std::unique_ptr<ChunkChecksum> chunkChecksum;
-#endif // ENABLE_MESSAGE_DIGEST
+
 private:
   std::unique_ptr<Signature> signature_;
 public:
diff --git a/src/MetalinkParserController.cc b/src/MetalinkParserController.cc
index e3fbd598..91ce7053 100644
--- a/src/MetalinkParserController.cc
+++ b/src/MetalinkParserController.cc
@@ -46,11 +46,9 @@
 #include "uri.h"
 #include "Signature.h"
 #include "util.h"
-#ifdef ENABLE_MESSAGE_DIGEST
-# include "Checksum.h"
-# include "ChunkChecksum.h"
-# include "MessageDigest.h"
-#endif // ENABLE_MESSAGE_DIGEST
+#include "Checksum.h"
+#include "ChunkChecksum.h"
+#include "MessageDigest.h"
 #ifdef ENABLE_BITTORRENT
 # include "magnet.h"
 #endif // ENABLE_BITTORRENT
@@ -78,11 +76,9 @@ void MetalinkParserController::newEntryTransaction()
   tEntry_ = make_unique<MetalinkEntry>();
   tResource_.reset();
   tMetaurl_.reset();
-#ifdef ENABLE_MESSAGE_DIGEST
   tChecksum_.reset();
   tChunkChecksumV4_.reset();
   tChunkChecksum_.reset();
-#endif // ENABLE_MESSAGE_DIGEST
 }
 
 void MetalinkParserController::setFileNameOfEntry(std::string filename)
@@ -263,17 +259,14 @@ void MetalinkParserController::cancelResourceTransaction()
 
 void MetalinkParserController::newChecksumTransaction()
 {
-#ifdef ENABLE_MESSAGE_DIGEST
   if(!tEntry_) {
     return;
   }
   tChecksum_ = make_unique<Checksum>();
-#endif // ENABLE_MESSAGE_DIGEST
 }
 
 void MetalinkParserController::setTypeOfChecksum(std::string type)
 {
-#ifdef ENABLE_MESSAGE_DIGEST
   if(!tChecksum_) {
     return;
   }
@@ -283,12 +276,10 @@ void MetalinkParserController::setTypeOfChecksum(std::string type)
   } else {
     cancelChecksumTransaction();
   }
-#endif // ENABLE_MESSAGE_DIGEST
 }
 
 void MetalinkParserController::setHashOfChecksum(std::string md)
 {
-#ifdef ENABLE_MESSAGE_DIGEST
   if(!tChecksum_) {
     return;
   }
@@ -297,12 +288,10 @@ void MetalinkParserController::setHashOfChecksum(std::string md)
   } else {
     cancelChecksumTransaction();
   }
-#endif // ENABLE_MESSAGE_DIGEST
 }
 
 void MetalinkParserController::commitChecksumTransaction()
 {
-#ifdef ENABLE_MESSAGE_DIGEST
   if(!tChecksum_) {
     return;
   }
@@ -312,30 +301,24 @@ void MetalinkParserController::commitChecksumTransaction()
     tEntry_->checksum = std::move(tChecksum_);
   }
   tChecksum_.reset();
-#endif // ENABLE_MESSAGE_DIGEST
 }
 
 void MetalinkParserController::cancelChecksumTransaction()
 {
-#ifdef ENABLE_MESSAGE_DIGEST
   tChecksum_.reset();
-#endif // ENABLE_MESSAGE_DIGEST
 }
 
 void MetalinkParserController::newChunkChecksumTransactionV4()
 {
-#ifdef ENABLE_MESSAGE_DIGEST
   if(!tEntry_) {
     return;
   }
   tChunkChecksumV4_ = make_unique<ChunkChecksum>();
   tempChunkChecksumsV4_.clear();
-#endif // ENABLE_MESSAGE_DIGEST
 }
 
 void MetalinkParserController::setTypeOfChunkChecksumV4(std::string type)
 {
-#ifdef ENABLE_MESSAGE_DIGEST
   if(!tChunkChecksumV4_) {
     return;
   }
@@ -345,12 +328,10 @@ void MetalinkParserController::setTypeOfChunkChecksumV4(std::string type)
   } else {
     cancelChunkChecksumTransactionV4();
   }
-#endif // ENABLE_MESSAGE_DIGEST
 }
 
 void MetalinkParserController::setLengthOfChunkChecksumV4(size_t length)
 {
-#ifdef ENABLE_MESSAGE_DIGEST
   if(!tChunkChecksumV4_) {
     return;
   }
@@ -359,12 +340,10 @@ void MetalinkParserController::setLengthOfChunkChecksumV4(size_t length)
   } else {
     cancelChunkChecksumTransactionV4();
   }
-#endif // ENABLE_MESSAGE_DIGEST
 }
 
 void MetalinkParserController::addHashOfChunkChecksumV4(std::string md)
 {
-#ifdef ENABLE_MESSAGE_DIGEST
   if(!tChunkChecksumV4_) {
     return;
   }
@@ -373,12 +352,10 @@ void MetalinkParserController::addHashOfChunkChecksumV4(std::string md)
   } else {
     cancelChunkChecksumTransactionV4();
   }
-#endif // ENABLE_MESSAGE_DIGEST
 }
 
 void MetalinkParserController::commitChunkChecksumTransactionV4()
 {
-#ifdef ENABLE_MESSAGE_DIGEST
   if(!tChunkChecksumV4_) {
     return;
   }
@@ -389,30 +366,24 @@ void MetalinkParserController::commitChunkChecksumTransactionV4()
     tEntry_->chunkChecksum = std::move(tChunkChecksumV4_);
   }
   tChunkChecksumV4_.reset();
-#endif // ENABLE_MESSAGE_DIGEST
 }
 
 void MetalinkParserController::cancelChunkChecksumTransactionV4()
 {
-#ifdef ENABLE_MESSAGE_DIGEST
   tChunkChecksumV4_.reset();
-#endif // ENABLE_MESSAGE_DIGEST
 }
 
 void MetalinkParserController::newChunkChecksumTransaction()
 {
-#ifdef ENABLE_MESSAGE_DIGEST
   if(!tEntry_) {
     return;
   }
   tChunkChecksum_ = make_unique<ChunkChecksum>();
   tempChunkChecksums_.clear();
-#endif // ENABLE_MESSAGE_DIGEST
 }
 
 void MetalinkParserController::setTypeOfChunkChecksum(std::string type)
 {
-#ifdef ENABLE_MESSAGE_DIGEST
   if(!tChunkChecksum_) {
     return;
   }
@@ -422,12 +393,10 @@ void MetalinkParserController::setTypeOfChunkChecksum(std::string type)
   } else {
     cancelChunkChecksumTransaction();
   }
-#endif // ENABLE_MESSAGE_DIGEST
 }
 
 void MetalinkParserController::setLengthOfChunkChecksum(size_t length)
 {
-#ifdef ENABLE_MESSAGE_DIGEST
   if(!tChunkChecksum_) {
     return;
   }
@@ -436,13 +405,11 @@ void MetalinkParserController::setLengthOfChunkChecksum(size_t length)
   } else {
     cancelChunkChecksumTransaction();
   }
-#endif // ENABLE_MESSAGE_DIGEST
 }
 
 void MetalinkParserController::addHashOfChunkChecksum(size_t order,
                                                       std::string md)
 {
-#ifdef ENABLE_MESSAGE_DIGEST
   if(!tChunkChecksum_) {
     return;
   }
@@ -451,22 +418,18 @@ void MetalinkParserController::addHashOfChunkChecksum(size_t order,
   } else {
     cancelChunkChecksumTransaction();
   }
-#endif // ENABLE_MESSAGE_DIGEST
 }
 
 void MetalinkParserController::createNewHashOfChunkChecksum(size_t order)
 {
-#ifdef ENABLE_MESSAGE_DIGEST
   if(!tChunkChecksum_) {
     return;
   }
   tempHashPair_.first = order;
-#endif // ENABLE_MESSAGE_DIGEST
 }
 
 void MetalinkParserController::setMessageDigestOfChunkChecksum(std::string md)
 {
-#ifdef ENABLE_MESSAGE_DIGEST
   if(!tChunkChecksum_) {
     return;
   }
@@ -475,22 +438,18 @@ void MetalinkParserController::setMessageDigestOfChunkChecksum(std::string md)
   } else {
     cancelChunkChecksumTransaction();
   }
-#endif // ENABLE_MESSAGE_DIGEST
 }
 
 void MetalinkParserController::addHashOfChunkChecksum()
 {
-#ifdef ENABLE_MESSAGE_DIGEST
   if(!tChunkChecksum_) {
     return;
   }
   tempChunkChecksums_.push_back(tempHashPair_);
-#endif // ENABLE_MESSAGE_DIGEST
 }
 
 void MetalinkParserController::commitChunkChecksumTransaction()
 {
-#ifdef ENABLE_MESSAGE_DIGEST
   if(!tChunkChecksum_) {
     return;
   }
@@ -508,14 +467,11 @@ void MetalinkParserController::commitChunkChecksumTransaction()
     tEntry_->chunkChecksum = std::move(tChunkChecksum_);
   }
   tChunkChecksum_.reset();
-#endif // ENABLE_MESSAGE_DIGEST
 }
 
 void MetalinkParserController::cancelChunkChecksumTransaction()
 {
-#ifdef ENABLE_MESSAGE_DIGEST
   tChunkChecksum_.reset();
-#endif // ENABLE_MESSAGE_DIGEST
 }
 
 void MetalinkParserController::newSignatureTransaction()
diff --git a/src/MetalinkParserController.h b/src/MetalinkParserController.h
index 4ff11fff..61e204b4 100644
--- a/src/MetalinkParserController.h
+++ b/src/MetalinkParserController.h
@@ -50,10 +50,8 @@ class MetalinkResource;
 class MetalinkMetaurl;
 class Signature;
 
-#ifdef ENABLE_MESSAGE_DIGEST
 class Checksum;
 class ChunkChecksum;
-#endif // ENABLE_MESSAGE_DIGEST
 
 class MetalinkParserController {
 private:
@@ -64,7 +62,7 @@ private:
   std::unique_ptr<MetalinkResource> tResource_;
 
   std::unique_ptr<MetalinkMetaurl> tMetaurl_;
-#ifdef ENABLE_MESSAGE_DIGEST
+
   std::unique_ptr<Checksum> tChecksum_;
 
   std::unique_ptr<ChunkChecksum> tChunkChecksumV4_; // Metalink4Spec
@@ -77,8 +75,6 @@ private:
 
   std::pair<size_t, std::string> tempHashPair_; // Metalink3Spec
 
-#endif // ENABLE_MESSAGE_DIGEST
-
   std::unique_ptr<Signature> tSignature_;
   std::string baseUri_;
 public:
diff --git a/src/MetalinkParserStateV3Impl.cc b/src/MetalinkParserStateV3Impl.cc
index 5b658999..056fe579 100644
--- a/src/MetalinkParserStateV3Impl.cc
+++ b/src/MetalinkParserStateV3Impl.cc
@@ -194,7 +194,6 @@ void VerificationMetalinkParserState::beginElement
   if(!checkNsUri(nsUri)) {
     psm->setSkipTagState();
   } else
-#ifdef ENABLE_MESSAGE_DIGEST
     if(strcmp(localname, "hash") == 0) {
       psm->setHashState();
       auto itr = findAttr(attrs, "type", METALINK3_NAMESPACE_URI);
@@ -231,7 +230,6 @@ void VerificationMetalinkParserState::beginElement
       psm->setLengthOfChunkChecksum(length);
       psm->setTypeOfChunkChecksum(type);
     } else
-#endif // ENABLE_MESSAGE_DIGEST
       if(strcmp(localname, "signature") == 0) {
         psm->setSignatureState();
         auto itr = findAttr(attrs, "type", METALINK3_NAMESPACE_URI);
diff --git a/src/MetalinkParserStateV4Impl.cc b/src/MetalinkParserStateV4Impl.cc
index a10e5d88..ee9edf88 100644
--- a/src/MetalinkParserStateV4Impl.cc
+++ b/src/MetalinkParserStateV4Impl.cc
@@ -166,7 +166,6 @@ void FileMetalinkParserStateV4::beginElement
     psm->setLocationOfResource(location);
     psm->setPriorityOfResource(priority);
   }
-#ifdef ENABLE_MESSAGE_DIGEST
   else if(strcmp(localname, "hash") == 0) {
     psm->setHashStateV4();
     auto itr = findAttr(attrs, "type", METALINK4_NAMESPACE_URI);
@@ -203,7 +202,6 @@ void FileMetalinkParserStateV4::beginElement
     psm->setLengthOfChunkChecksumV4(length);
     psm->setTypeOfChunkChecksumV4(type);
   }
-#endif // ENABLE_MESSAGE_DIGEST
   else if(strcmp(localname, "signature") == 0) {
     psm->setSignatureStateV4();
     auto itr = findAttr(attrs, "mediatype", METALINK4_NAMESPACE_URI);
diff --git a/src/OptionHandlerFactory.cc b/src/OptionHandlerFactory.cc
index 9d24a243..7ef8a325 100644
--- a/src/OptionHandlerFactory.cc
+++ b/src/OptionHandlerFactory.cc
@@ -140,7 +140,6 @@ std::vector<OptionHandler*> OptionHandlerFactory::createOptionHandlers()
     op->addTag(TAG_ADVANCED);
     handlers.push_back(op);
   }
-#ifdef ENABLE_MESSAGE_DIGEST
   {
     OptionHandler* op(new BooleanOptionHandler
                       (PREF_CHECK_INTEGRITY,
@@ -158,7 +157,6 @@ std::vector<OptionHandler*> OptionHandlerFactory::createOptionHandlers()
     op->setChangeOptionForReserved(true);
     handlers.push_back(op);
   }
-#endif // ENABLE_MESSAGE_DIGEST
   {
     OptionHandler* op(new BooleanOptionHandler
                       (PREF_CONDITIONAL_GET,
@@ -426,7 +424,6 @@ std::vector<OptionHandler*> OptionHandlerFactory::createOptionHandlers()
     op->setInitialOption(true);
     handlers.push_back(op);
   }
-#ifdef ENABLE_MESSAGE_DIGEST
   {
     OptionHandler* op(new BooleanOptionHandler
                       (PREF_HASH_CHECK_ONLY,
@@ -443,7 +440,6 @@ std::vector<OptionHandler*> OptionHandlerFactory::createOptionHandlers()
     op->setChangeOptionForReserved(true);
     handlers.push_back(op);
   }
-#endif // ENABLE_MESSAGE_DIGEST
   {
     OptionHandler* op(new BooleanOptionHandler
                       (PREF_HUMAN_READABLE,
@@ -693,7 +689,6 @@ std::vector<OptionHandler*> OptionHandlerFactory::createOptionHandlers()
     op->addTag(TAG_ADVANCED);
     handlers.push_back(op);
   }
-#ifdef ENABLE_MESSAGE_DIGEST
   {
     OptionHandler* op(new BooleanOptionHandler
                       (PREF_REALTIME_CHUNK_CHECKSUM,
@@ -707,7 +702,6 @@ std::vector<OptionHandler*> OptionHandlerFactory::createOptionHandlers()
     op->setChangeOptionForReserved(true);
     handlers.push_back(op);
   }
-#endif // ENABLE_MESSAGE_DIGEST
   {
     OptionHandler* op(new BooleanOptionHandler
                       (PREF_REMOVE_CONTROL_FILE,
@@ -914,7 +908,6 @@ std::vector<OptionHandler*> OptionHandlerFactory::createOptionHandlers()
     handlers.push_back(op);
   }
   // HTTP/FTP options
-#ifdef ENABLE_MESSAGE_DIGEST
   {
     OptionHandler* op(new ChecksumOptionHandler
                       (PREF_CHECKSUM,
@@ -926,7 +919,6 @@ std::vector<OptionHandler*> OptionHandlerFactory::createOptionHandlers()
     op->setChangeOptionForReserved(true);
     handlers.push_back(op);
   }
-#endif // ENABLE_MESSAGE_DIGEST
   {
     OptionHandler* op(new NumberOptionHandler
                       (PREF_CONNECT_TIMEOUT,
diff --git a/src/OptionHandlerImpl.cc b/src/OptionHandlerImpl.cc
index 970ebfe4..0fb39758 100644
--- a/src/OptionHandlerImpl.cc
+++ b/src/OptionHandlerImpl.cc
@@ -61,9 +61,7 @@
 #include "SegList.h"
 #include "array_fun.h"
 #include "help_tags.h"
-#ifdef ENABLE_MESSAGE_DIGEST
-# include "MessageDigest.h"
-#endif // ENABLE_MESSAGE_DIGEST
+#include "MessageDigest.h"
 
 namespace aria2 {
 
@@ -368,7 +366,6 @@ std::string IndexOutOptionHandler::createPossibleValuesString() const
   return "INDEX=PATH";
 }
 
-#ifdef ENABLE_MESSAGE_DIGEST
 ChecksumOptionHandler::ChecksumOptionHandler
 (PrefPtr pref,
  const char* description,
@@ -397,7 +394,6 @@ std::string ChecksumOptionHandler::createPossibleValuesString() const
 {
   return "HASH_TYPE=HEX_DIGEST";
 }
-#endif // ENABLE_MESSAGE_DIGEST
 
 ParameterOptionHandler::ParameterOptionHandler
 (PrefPtr pref,
diff --git a/src/OptionHandlerImpl.h b/src/OptionHandlerImpl.h
index a4ef2a71..7753a96b 100644
--- a/src/OptionHandlerImpl.h
+++ b/src/OptionHandlerImpl.h
@@ -172,7 +172,6 @@ public:
   virtual std::string createPossibleValuesString() const CXX11_OVERRIDE;
 };
 
-#ifdef ENABLE_MESSAGE_DIGEST
 class ChecksumOptionHandler : public AbstractOptionHandler {
 public:
   ChecksumOptionHandler(PrefPtr pref,
@@ -183,7 +182,6 @@ public:
     CXX11_OVERRIDE;
   virtual std::string createPossibleValuesString() const CXX11_OVERRIDE;
 };
-#endif // ENABLE_MESSAGE_DIGEST
 
 class ParameterOptionHandler : public AbstractOptionHandler {
 private:
diff --git a/src/Piece.cc b/src/Piece.cc
index 668e2131..55b5a64b 100644
--- a/src/Piece.cc
+++ b/src/Piece.cc
@@ -46,9 +46,7 @@
 #include "LogFactory.h"
 #include "fmt.h"
 #include "DiskAdaptor.h"
-#ifdef ENABLE_MESSAGE_DIGEST
-# include "MessageDigest.h"
-#endif // ENABLE_MESSAGE_DIGEST
+#include "MessageDigest.h"
 
 namespace aria2 {
 
@@ -58,9 +56,7 @@ Piece::Piece()
     index_(0),
     length_(0),
     blockLength_(BLOCK_LENGTH),
-#ifdef ENABLE_MESSAGE_DIGEST
     nextBegin_(0),
-#endif // ENABLE_MESSAGE_DIGEST
     usedBySegment_(false)
 {}
 
@@ -70,9 +66,7 @@ Piece::Piece(size_t index, int32_t length, int32_t blockLength)
    index_(index),
    length_(length),
    blockLength_(blockLength),
-#ifdef ENABLE_MESSAGE_DIGEST
-    nextBegin_(0),
-#endif // ENABLE_MESSAGE_DIGEST
+   nextBegin_(0),
    usedBySegment_(false)
 {}
 
@@ -208,8 +202,6 @@ int32_t Piece::getCompletedLength()
   return bitfield_->getCompletedLength();
 }
 
-#ifdef ENABLE_MESSAGE_DIGEST
-
 void Piece::setHashType(const std::string& hashType)
 {
   hashType_ = hashType;
@@ -304,8 +296,6 @@ void Piece::destroyHashContext()
   nextBegin_ = 0;
 }
 
-#endif // ENABLE_MESSAGE_DIGEST
-
 bool Piece::usedBy(cuid_t cuid) const
 {
   return std::find(users_.begin(), users_.end(), cuid) != users_.end();
diff --git a/src/Piece.h b/src/Piece.h
index 40c62693..2389c3ac 100644
--- a/src/Piece.h
+++ b/src/Piece.h
@@ -50,32 +50,21 @@ class BitfieldMan;
 class WrDiskCache;
 class WrDiskCacheEntry;
 class DiskAdaptor;
-
-#ifdef ENABLE_MESSAGE_DIGEST
-
 class MessageDigest;
 
-#endif // ENABLE_MESSAGE_DIGEST
-
 class Piece {
 private:
   BitfieldMan* bitfield_;
   WrDiskCacheEntry* wrCache_;
-#ifdef ENABLE_MESSAGE_DIGEST
   std::unique_ptr<MessageDigest> mdctx_;
-#endif // ENABLE_MESSAGE_DIGEST
   std::vector<cuid_t> users_;
-#ifdef ENABLE_MESSAGE_DIGEST
   std::string hashType_;
-#endif // ENABLE_MESSAGE_DIGEST
 
   size_t index_;
 
   int32_t length_;
   int32_t blockLength_;
-#ifdef ENABLE_MESSAGE_DIGEST
   int32_t nextBegin_;
-#endif // ENABLE_MESSAGE_DIGEST
 
   bool usedBySegment_;
 
@@ -158,8 +147,6 @@ public:
   // Calculates completed length
   int32_t getCompletedLength();
 
-#ifdef ENABLE_MESSAGE_DIGEST
-
   void setHashType(const std::string& hashType);
 
   // Updates hash value. This function compares begin and private variable
@@ -181,8 +168,6 @@ public:
   // cached data and data on disk.
   std::string getDigestWithWrCache(size_t pieceLength,
                                    const std::shared_ptr<DiskAdaptor>& adaptor);
-#endif // ENABLE_MESSAGE_DIGEST
-
   /**
    * Loses current bitfield state.
    */
diff --git a/src/PieceHashCheckIntegrityEntry.cc b/src/PieceHashCheckIntegrityEntry.cc
index 1356fc11..2935876e 100644
--- a/src/PieceHashCheckIntegrityEntry.cc
+++ b/src/PieceHashCheckIntegrityEntry.cc
@@ -58,13 +58,11 @@ bool PieceHashCheckIntegrityEntry::isValidationReady()
 
 void PieceHashCheckIntegrityEntry::initValidator()
 {
-#ifdef ENABLE_MESSAGE_DIGEST
   auto validator = make_unique<IteratableChunkChecksumValidator>
     (getRequestGroup()->getDownloadContext(),
      getRequestGroup()->getPieceStorage());
   validator->init();
   setValidator(std::move(validator));
-#endif // ENABLE_MESSAGE_DIGEST
 }
 
 } // namespace aria2
diff --git a/src/PiecedSegment.cc b/src/PiecedSegment.cc
index e1ebcdde..819e8d70 100644
--- a/src/PiecedSegment.cc
+++ b/src/PiecedSegment.cc
@@ -90,8 +90,6 @@ void PiecedSegment::updateWrittenLength(int32_t bytes)
   writtenLength_ = newWrittenLength;
 }
 
-#ifdef ENABLE_MESSAGE_DIGEST
-
 bool PiecedSegment::updateHash
 (int32_t begin,
  const unsigned char* data,
@@ -110,18 +108,12 @@ std::string PiecedSegment::getDigest()
   return piece_->getDigest();
 }
 
-#endif // ENABLE_MESSAGE_DIGEST
-
 void PiecedSegment::clear(WrDiskCache* diskCache)
 {
   writtenLength_ = 0;
   piece_->clearAllBlock(diskCache);
 
-#ifdef ENABLE_MESSAGE_DIGEST
-
   piece_->destroyHashContext();
-
-#endif // ENABLE_MESSAGE_DIGEST
 }
 
 std::shared_ptr<Piece> PiecedSegment::getPiece() const
diff --git a/src/PiecedSegment.h b/src/PiecedSegment.h
index 375ef3a0..30270f7b 100644
--- a/src/PiecedSegment.h
+++ b/src/PiecedSegment.h
@@ -76,8 +76,6 @@ public:
 
   virtual void updateWrittenLength(int32_t bytes) CXX11_OVERRIDE;
 
-#ifdef ENABLE_MESSAGE_DIGEST
-
   // `begin' is a offset inside this segment.
   virtual bool updateHash
   (int32_t begin,
@@ -88,8 +86,6 @@ public:
 
   virtual std::string getDigest() CXX11_OVERRIDE;
 
-#endif // ENABLE_MESSAGE_DIGEST
-
   virtual void clear(WrDiskCache* diskCache) CXX11_OVERRIDE;
 
   virtual std::shared_ptr<Piece> getPiece() const CXX11_OVERRIDE;
diff --git a/src/RequestGroup.cc b/src/RequestGroup.cc
index 2b3e1410..d0035212 100644
--- a/src/RequestGroup.cc
+++ b/src/RequestGroup.cc
@@ -79,10 +79,8 @@
 #include "Segment.h"
 #include "SocketRecvBuffer.h"
 #include "RequestGroupCriteria.h"
-#ifdef ENABLE_MESSAGE_DIGEST
-# include "CheckIntegrityCommand.h"
-# include "ChecksumCheckIntegrityEntry.h"
-#endif // ENABLE_MESSAGE_DIGEST
+#include "CheckIntegrityCommand.h"
+#include "ChecksumCheckIntegrityEntry.h"
 #ifdef ENABLE_BITTORRENT
 # include "bittorrent_helper.h"
 # include "BtRegistry.h"
@@ -240,14 +238,12 @@ std::unique_ptr<CheckIntegrityEntry> RequestGroup::createCheckIntegrityEntry()
     // issue checksum verification and download fails without it.
     loadAndOpenFile(infoFile);
     if(downloadFinished()) {
-#ifdef ENABLE_MESSAGE_DIGEST
       if(downloadContext_->isChecksumVerificationNeeded()) {
         A2_LOG_INFO(MSG_HASH_CHECK_NOT_DONE);
         auto tempEntry = make_unique<ChecksumCheckIntegrityEntry>(this);
         tempEntry->setRedownload(true);
         return std::move(tempEntry);
       }
-#endif // ENABLE_MESSAGE_DIGEST
       downloadContext_->setChecksumVerified(true);
       A2_LOG_NOTICE(fmt(MSG_DOWNLOAD_ALREADY_COMPLETED,
                         gid_->toHex().c_str(),
@@ -257,7 +253,6 @@ std::unique_ptr<CheckIntegrityEntry> RequestGroup::createCheckIntegrityEntry()
     return make_unique<StreamCheckIntegrityEntry>(this);
   }
 
-#ifdef ENABLE_MESSAGE_DIGEST
   if (downloadFinishedByFileLength() &&
       downloadContext_->isChecksumVerificationAvailable()) {
     pieceStorage_->markAllPiecesDone();
@@ -266,7 +261,6 @@ std::unique_ptr<CheckIntegrityEntry> RequestGroup::createCheckIntegrityEntry()
     tempEntry->setRedownload(true);
     return std::move(tempEntry);
   } 
-#endif // ENABLE_MESSAGE_DIGEST
 
   loadAndOpenFile(infoFile);
   return make_unique<StreamCheckIntegrityEntry>(this);
@@ -520,7 +514,6 @@ void RequestGroup::processCheckIntegrityEntry(
   if(actualFileSize > downloadContext_->getTotalLength()) {
     entry->cutTrailingGarbage();
   }
-#ifdef ENABLE_MESSAGE_DIGEST
   if((option_->getAsBool(PREF_CHECK_INTEGRITY) ||
       downloadContext_->isChecksumVerificationNeeded()) &&
      entry->isValidationReady()) {
@@ -535,7 +528,6 @@ void RequestGroup::processCheckIntegrityEntry(
     e->getCheckIntegrityMan()->pushEntry(std::move(entry));
     return;
   }
-#endif // ENABLE_MESSAGE_DIGEST
 
   entry->onDownloadIncomplete(commands, e);
 }
@@ -664,16 +656,12 @@ void RequestGroup::adjustFilename(
       outfile.size() <= downloadContext_->getTotalLength()) {
     // File exists but user decided to resume it.
   }
-#ifdef ENABLE_MESSAGE_DIGEST
   else if(outfile.exists() && isCheckIntegrityReady()) {
       // check-integrity existing file
   }
-#endif // ENABLE_MESSAGE_DIGEST
   else {
     shouldCancelDownloadForSafety();
-#ifdef ENABLE_MESSAGE_DIGEST
   }
-#endif // ENABLE_MESSAGE_DIGEST
 }
 
 void RequestGroup::removeDefunctControlFile(
@@ -709,11 +697,9 @@ void RequestGroup::loadAndOpenFile(
         pieceStorage_->getDiskAdaptor()->openExistingFile();
         pieceStorage_->markPiecesDone(outfile.size());
       }
-#ifdef ENABLE_MESSAGE_DIGEST
       else if (outfile.exists() && isCheckIntegrityReady()) {
         pieceStorage_->getDiskAdaptor()->openExistingFile();
       }
-#endif // ENABLE_MESSAGE_DIGEST
       else {
         pieceStorage_->getDiskAdaptor()->initAndOpenFile();
       }
diff --git a/src/RpcMethodImpl.cc b/src/RpcMethodImpl.cc
index c920a4aa..0ecf9f3e 100644
--- a/src/RpcMethodImpl.cc
+++ b/src/RpcMethodImpl.cc
@@ -66,10 +66,8 @@
 #include "base64.h"
 #include "BitfieldMan.h"
 #include "SessionSerializer.h"
-#ifdef ENABLE_MESSAGE_DIGEST
-# include "MessageDigest.h"
-# include "message_digest_helper.h"
-#endif // ENABLE_MESSAGE_DIGEST
+#include "MessageDigest.h"
+#include "message_digest_helper.h"
 #ifdef ENABLE_BITTORRENT
 # include "bittorrent_helper.h"
 # include "BtRegistry.h"
@@ -254,7 +252,6 @@ std::unique_ptr<ValueBase> AddUriRpcMethod::process
   }
 }
 
-#ifdef ENABLE_MESSAGE_DIGEST
 namespace {
 std::string getHexSha1(const std::string& s)
 {
@@ -264,7 +261,6 @@ std::string getHexSha1(const std::string& s)
   return util::toHex(hash, sizeof(hash));
 }
 } // namespace
-#endif // ENABLE_MESSAGE_DIGEST
 
 #ifdef ENABLE_BITTORRENT
 std::unique_ptr<ValueBase> AddTorrentRpcMethod::process
@@ -341,7 +337,6 @@ std::unique_ptr<ValueBase> AddMetalinkRpcMethod::process
   size_t pos = posGiven ? posParam->i() : 0;
 
   std::vector<std::shared_ptr<RequestGroup>> result;
-#ifdef ENABLE_MESSAGE_DIGEST
   std::string filename;
   if(requestOption->getAsBool(PREF_RPC_SAVE_UPLOAD_METADATA)) {
     // TODO RFC5854 Metalink has the extension .meta4 and Metalink
@@ -365,9 +360,6 @@ std::unique_ptr<ValueBase> AddMetalinkRpcMethod::process
   } else {
     createRequestGroupForMetalink(result, requestOption, metalinkParam->s());
   }
-#else // !ENABLE_MESSAGE_DIGEST
-  createRequestGroupForMetalink(result, requestOption, metalinkParam->s());
-#endif // !ENABLE_MESSAGE_DIGEST
   auto gids = List::g();
   if(!result.empty()) {
     if(posGiven) {
diff --git a/src/Segment.h b/src/Segment.h
index dd17826c..ad9355ea 100644
--- a/src/Segment.h
+++ b/src/Segment.h
@@ -66,8 +66,6 @@ public:
 
   virtual void updateWrittenLength(int32_t bytes) = 0;
 
-#ifdef ENABLE_MESSAGE_DIGEST
-
   // `begin' is a offset inside this segment.
   virtual bool updateHash
   (int32_t begin,
@@ -78,8 +76,6 @@ public:
 
   virtual std::string getDigest() = 0;
 
-#endif // ENABLE_MESSAGE_DIGEST
-
   virtual void clear(WrDiskCache* diskCache) = 0;
 
   virtual std::shared_ptr<Piece> getPiece() const = 0;
diff --git a/src/SinkStreamFilter.cc b/src/SinkStreamFilter.cc
index 88420cfc..28ea7fe0 100644
--- a/src/SinkStreamFilter.cc
+++ b/src/SinkStreamFilter.cc
@@ -88,11 +88,9 @@ ssize_t SinkStreamFilter::transform
     } else {
       out->writeData(inbuf, wlen, segment->getPositionToWrite());
     }
-#ifdef ENABLE_MESSAGE_DIGEST
     if(hashUpdate_) {
       segment->updateHash(segment->getWrittenLength(), inbuf, wlen);
     }
-#endif // ENABLE_MESSAGE_DIGEST
     segment->updateWrittenLength(wlen);
   } else {
     wlen = 0;
diff --git a/src/download_helper.cc b/src/download_helper.cc
index fc23682f..931ab505 100644
--- a/src/download_helper.cc
+++ b/src/download_helper.cc
@@ -143,7 +143,6 @@ std::shared_ptr<RequestGroup> createRequestGroup
   dctx->getFirstFileEntry()->setUris(uris);
   dctx->getFirstFileEntry()->setMaxConnectionPerServer
     (option->getAsInt(PREF_MAX_CONNECTION_PER_SERVER));
-#ifdef ENABLE_MESSAGE_DIGEST
   const std::string& checksum = option->get(PREF_CHECKSUM);
   if(!checksum.empty()) {
     auto p = util::divide(std::begin(checksum), std::end(checksum), '=');
@@ -153,7 +152,6 @@ std::shared_ptr<RequestGroup> createRequestGroup
     dctx->setDigest(hashType,
                     util::fromHex(std::begin(hexDigest), std::end(hexDigest)));
   }
-#endif // ENABLE_MESSAGE_DIGEST
   rg->setDownloadContext(dctx);
   rg->setPauseRequested(option->getAsBool(PREF_PAUSE));
   removeOneshotOption(option);
diff --git a/src/util.cc b/src/util.cc
index 3d9e8548..7e7932ab 100644
--- a/src/util.cc
+++ b/src/util.cc
@@ -85,10 +85,8 @@
 #include "SocketCore.h"
 #include "Lock.h"
 
-#ifdef ENABLE_MESSAGE_DIGEST
-# include "MessageDigest.h"
-# include "message_digest_helper.h"
-#endif // ENABLE_MESSAGE_DIGEST
+#include "MessageDigest.h"
+#include "message_digest_helper.h"
 
 // For libc6 which doesn't define ULLONG_MAX properly because of broken limits.h
 #ifndef ULLONG_MAX
@@ -1641,14 +1639,10 @@ std::string fixTaintedBasename(const std::string& src)
 
 void generateRandomKey(unsigned char* key)
 {
-#ifdef ENABLE_MESSAGE_DIGEST
   unsigned char bytes[40];
   generateRandomData(bytes, sizeof(bytes));
   message_digest::digest(key, 20, MessageDigest::sha1().get(), bytes,
                          sizeof(bytes));
-#else // !ENABLE_MESSAGE_DIGEST
-  generateRandomData(key, 20);
-#endif // !ENABLE_MESSAGE_DIGEST
 }
 
 // Returns true is given numeric ipv4addr is in Private Address Space.
diff --git a/src/version_usage.cc b/src/version_usage.cc
index 49f55658..6d9fc3f7 100644
--- a/src/version_usage.cc
+++ b/src/version_usage.cc
@@ -40,9 +40,7 @@
 
 #include "a2io.h"
 #include "FeatureConfig.h"
-#ifdef ENABLE_MESSAGE_DIGEST
-# include "MessageDigest.h"
-#endif // ENABLE_MESSAGE_DIGEST
+#include "MessageDigest.h"
 #include "help_tags.h"
 #include "prefs.h"
 #include "fmt.h"
@@ -70,10 +68,8 @@ void showVersion() {
             << _("** Configuration **") << "\n"
             << _("Enabled Features") << ": "
             << featureSummary() << "\n"
-#ifdef ENABLE_MESSAGE_DIGEST
             << _("Hash Algorithms") << ": "
             << MessageDigest::getSupportedHashTypeString() << "\n"
-#endif // ENABLE_MESSAGE_DIGEST
             << _("Libraries") << ": "
             << usedLibs() << "\n"
             << "\n"