diff --git a/src/3rdparty/md5/md5.cpp b/src/3rdparty/md5/md5.cpp
--- a/src/3rdparty/md5/md5.cpp
+++ b/src/3rdparty/md5/md5.cpp
@@ -297,7 +297,7 @@ void Md5::Append(const void *data, const
 	if (left) memcpy(this->buf, p, left);
 }
 
-void Md5::Finish(uint8 digest[16])
+void Md5::Finish(MD5Hash &digest)
 {
 	static const uint8 pad[64] = {
 		0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
diff --git a/src/3rdparty/md5/md5.h b/src/3rdparty/md5/md5.h
--- a/src/3rdparty/md5/md5.h
+++ b/src/3rdparty/md5/md5.h
@@ -53,6 +53,25 @@
 #ifndef MD5_INCLUDED
 #define MD5_INCLUDED
 
+/** The number of bytes in a MD5 hash. */
+static const size_t MD5_HASH_BYTES = 16;
+
+/** Container for storing a MD5 hash/checksum/digest. */
+using MD5Hash = std::array<byte, MD5_HASH_BYTES>;
+
+/**
+ * Exclusively-or one hash into another hash.
+ * @param lhs The hash to exclusively-or into.
+ * @param rhs The hash to exclusively-or with.
+ * @return Reference to \c lhs hash.
+ */
+inline MD5Hash &operator^=(MD5Hash &lhs, const MD5Hash &rhs)
+{
+	for (size_t i = 0; i < lhs.size(); i++) lhs[i] ^= rhs[i];
+	return lhs;
+}
+
+
 struct Md5 {
 private:
 	uint32 count[2]; ///< message length in bits, lsw first
@@ -64,7 +83,7 @@ private:
 public:
 	Md5();
 	void Append(const void *data, const size_t nbytes);
-	void Finish(uint8 digest[16]);
+	void Finish(MD5Hash &digest);
 };
 
 #endif /* MD5_INCLUDED */
diff --git a/src/base_media_base.h b/src/base_media_base.h
--- a/src/base_media_base.h
+++ b/src/base_media_base.h
@@ -14,6 +14,7 @@
 #include "gfx_type.h"
 #include "textfile_type.h"
 #include "textfile_gui.h"
+#include "3rdparty/md5/md5.h"
 #include <unordered_map>
 
 /* Forward declare these; can't do 'struct X' in functions as older GCCs barf on that */
@@ -31,7 +32,7 @@ struct MD5File {
 	};
 
 	std::string filename;        ///< filename
-	uint8 hash[16];              ///< md5 sum of the file
+	MD5Hash hash;                ///< md5 sum of the file
 	std::string missing_warning; ///< warning when this file is missing
 	ChecksumResult check_result; ///< cached result of md5 check
 
diff --git a/src/base_media_func.h b/src/base_media_func.h
--- a/src/base_media_func.h
+++ b/src/base_media_func.h
@@ -99,7 +99,7 @@ bool BaseSet<T, Tnum_files, Tsearch_in_t
 			return false;
 		}
 		const char *c = item->value->c_str();
-		for (uint i = 0; i < sizeof(file->hash) * 2; i++, c++) {
+		for (size_t i = 0; i < file->hash.size() * 2; i++, c++) {
 			uint j;
 			if ('0' <= *c && *c <= '9') {
 				j = *c - '0';
@@ -285,14 +285,11 @@ template <class Tbase_set> const char *T
 		if (s->shortname != ci->unique_id) continue;
 		if (!md5sum) return s->files[0].filename.c_str();
 
-		byte md5[16];
-		memset(md5, 0, sizeof(md5));
+		MD5Hash md5;
 		for (uint i = 0; i < Tbase_set::NUM_FILES; i++) {
-			for (uint j = 0; j < sizeof(md5); j++) {
-				md5[j] ^= s->files[i].hash[j];
-			}
+			md5 ^= s->files[i].hash;
 		}
-		if (memcmp(md5, ci->md5sum, sizeof(md5)) == 0) return s->files[0].filename.c_str();
+		if (md5 == ci->md5sum) return s->files[0].filename.c_str();
 	}
 	return nullptr;
 }
diff --git a/src/fios.cpp b/src/fios.cpp
--- a/src/fios.cpp
+++ b/src/fios.cpp
@@ -629,13 +629,12 @@ const char *FiosGetScreenshotDir()
 /** Basic data to distinguish a scenario. Used in the server list window */
 struct ScenarioIdentifier {
 	uint32 scenid;           ///< ID for the scenario (generated by content).
-	uint8 md5sum[16];        ///< MD5 checksum of file.
+	MD5Hash md5sum;          ///< MD5 checksum of file.
 	std::string filename;    ///< filename of the file.
 
 	bool operator == (const ScenarioIdentifier &other) const
 	{
-		return this->scenid == other.scenid &&
-				memcmp(this->md5sum, other.md5sum, sizeof(this->md5sum)) == 0;
+		return this->scenid == other.scenid && this->md5sum == other.md5sum;
 	}
 
 	bool operator != (const ScenarioIdentifier &other) const
@@ -714,7 +713,7 @@ const char *FindScenario(const ContentIn
 	_scanner.Scan(false);
 
 	for (ScenarioIdentifier &id : _scanner) {
-		if (md5sum ? (memcmp(id.md5sum, ci->md5sum, sizeof(id.md5sum)) == 0)
+		if (md5sum ? (id.md5sum == ci->md5sum)
 		           : (id.scenid == ci->unique_id)) {
 			return id.filename.c_str();
 		}
diff --git a/src/gamelog.cpp b/src/gamelog.cpp
--- a/src/gamelog.cpp
+++ b/src/gamelog.cpp
@@ -106,10 +106,10 @@ void Gamelog::Reset()
  * @param md5sum array of md5sum to print, if known
  * @param gc GrfConfig, if known
  */
-static void AddGrfInfo(std::back_insert_iterator<std::string> &output_iterator, uint32_t grfid, const uint8_t *md5sum, const GRFConfig *gc)
+static void AddGrfInfo(std::back_insert_iterator<std::string> &output_iterator, uint32_t grfid, const MD5Hash *md5sum, const GRFConfig *gc)
 {
 	if (md5sum != nullptr) {
-		fmt::format_to(output_iterator, "GRF ID {:08X}, checksum {}", BSWAP32(grfid), MD5SumToString(md5sum));
+		fmt::format_to(output_iterator, "GRF ID {:08X}, checksum {}", BSWAP32(grfid), MD5SumToString(*md5sum));
 	} else {
 		fmt::format_to(output_iterator, "GRF ID {:08X}", BSWAP32(grfid));
 	}
@@ -230,9 +230,9 @@ void Gamelog::Print(std::function<void(c
 /* virtual */ void LoggedChangeGRFAdd::FormatTo(std::back_insert_iterator<std::string> &output_iterator, GrfIDMapping &grf_names, GamelogActionType action_type)
 {
 	/* A NewGRF got added to the game, either at the start of the game (never an issue), or later on when it could be an issue. */
-	const GRFConfig *gc = FindGRFConfig(this->grfid, FGCM_EXACT, this->md5sum);
+	const GRFConfig *gc = FindGRFConfig(this->grfid, FGCM_EXACT, &this->md5sum);
 	fmt::format_to(output_iterator, "Added NewGRF: ");
-	AddGrfInfo(output_iterator, this->grfid, this->md5sum, gc);
+	AddGrfInfo(output_iterator, this->grfid, &this->md5sum, gc);
 	auto gm = grf_names.find(this->grfid);
 	if (gm != grf_names.end() && !gm->second.was_missing) fmt::format_to(output_iterator, ". Gamelog inconsistency: GrfID was already added!");
 	grf_names[this->grfid] = gc;
@@ -259,9 +259,9 @@ void Gamelog::Print(std::function<void(c
 /* virtual */ void LoggedChangeGRFChanged::FormatTo(std::back_insert_iterator<std::string> &output_iterator, GrfIDMapping &grf_names, GamelogActionType action_type)
 {
 	/* Another version of the same NewGRF got loaded. */
-	const GRFConfig *gc = FindGRFConfig(this->grfid, FGCM_EXACT, this->md5sum);
+	const GRFConfig *gc = FindGRFConfig(this->grfid, FGCM_EXACT, &this->md5sum);
 	fmt::format_to(output_iterator, "Compatible NewGRF loaded: ");
-	AddGrfInfo(output_iterator, this->grfid, this->md5sum, gc);
+	AddGrfInfo(output_iterator, this->grfid, &this->md5sum, gc);
 	if (grf_names.count(this->grfid) == 0) fmt::format_to(output_iterator, ". Gamelog inconsistency: GrfID was never added!");
 	grf_names[this->grfid] = gc;
 }
@@ -654,7 +654,7 @@ void Gamelog::GRFUpdate(const GRFConfig 
 				this->GRFMove(nl[n++]->ident.grfid, -(int)oi);
 			}
 		} else {
-			if (memcmp(og->ident.md5sum, ng->ident.md5sum, sizeof(og->ident.md5sum)) != 0) {
+			if (og->ident.md5sum != ng->ident.md5sum) {
 				/* md5sum changed, probably loading 'compatible' GRF */
 				this->GRFCompatible(&nl[n]->ident);
 			}
diff --git a/src/gfxinit.cpp b/src/gfxinit.cpp
--- a/src/gfxinit.cpp
+++ b/src/gfxinit.cpp
@@ -415,7 +415,7 @@ MD5File::ChecksumResult MD5File::CheckMD
 
 	Md5 checksum;
 	uint8 buffer[1024];
-	uint8 digest[16];
+	MD5Hash digest;
 	size_t len;
 
 	while ((len = fread(buffer, 1, (size > sizeof(buffer)) ? sizeof(buffer) : size, f)) != 0 && size != 0) {
@@ -426,7 +426,7 @@ MD5File::ChecksumResult MD5File::CheckMD
 	FioFCloseFile(f);
 
 	checksum.Finish(digest);
-	return memcmp(this->hash, digest, sizeof(this->hash)) == 0 ? CR_MATCH : CR_MISMATCH;
+	return this->hash == digest ? CR_MATCH : CR_MISMATCH;
 }
 
 /** Names corresponding to the GraphicsFileType */
diff --git a/src/misc.cpp b/src/misc.cpp
--- a/src/misc.cpp
+++ b/src/misc.cpp
@@ -77,7 +77,7 @@ std::string GenerateUid(std::string_view
 	std::string coding_string = fmt::format("{}{}{}", InteractiveRandom(), current_time, subject);
 
 	Md5 checksum;
-	uint8 digest[16];
+	MD5Hash digest;
 	checksum.Append(coding_string.c_str(), coding_string.length());
 	checksum.Finish(digest);
 
diff --git a/src/network/core/game_info.cpp b/src/network/core/game_info.cpp
--- a/src/network/core/game_info.cpp
+++ b/src/network/core/game_info.cpp
@@ -164,7 +164,7 @@ const NetworkServerGameInfo *GetCurrentN
 static void HandleIncomingNetworkGameInfoGRFConfig(GRFConfig *config, std::string name)
 {
 	/* Find the matching GRF file */
-	const GRFConfig *f = FindGRFConfig(config->ident.grfid, FGCM_EXACT, config->ident.md5sum);
+	const GRFConfig *f = FindGRFConfig(config->ident.grfid, FGCM_EXACT, &config->ident.md5sum);
 	if (f == nullptr) {
 		AddGRFTextToList(config->name, name.empty() ? GetString(STR_CONFIG_ERROR_INVALID_GRF_UNKNOWN) : name);
 		config->status = GCS_NOT_FOUND;
@@ -362,9 +362,8 @@ void DeserializeNetworkGameInfo(Packet *
  */
 void SerializeGRFIdentifier(Packet *p, const GRFIdentifier *grf)
 {
-	uint j;
 	p->Send_uint32(grf->grfid);
-	for (j = 0; j < sizeof(grf->md5sum); j++) {
+	for (size_t j = 0; j < grf->md5sum.size(); j++) {
 		p->Send_uint8(grf->md5sum[j]);
 	}
 }
@@ -376,9 +375,8 @@ void SerializeGRFIdentifier(Packet *p, c
  */
 void DeserializeGRFIdentifier(Packet *p, GRFIdentifier *grf)
 {
-	uint j;
 	grf->grfid = p->Recv_uint32();
-	for (j = 0; j < sizeof(grf->md5sum); j++) {
+	for (size_t j = 0; j < grf->md5sum.size(); j++) {
 		grf->md5sum[j] = p->Recv_uint8();
 	}
 }
diff --git a/src/network/core/tcp_content.cpp b/src/network/core/tcp_content.cpp
--- a/src/network/core/tcp_content.cpp
+++ b/src/network/core/tcp_content.cpp
@@ -70,7 +70,7 @@ std::optional<std::string> ContentInfo::
 			tmp = Game::GetScannerLibrary()->FindMainScript(this, true);
 			break;
 		case CONTENT_TYPE_NEWGRF: {
-			const GRFConfig *gc = FindGRFConfig(BSWAP32(this->unique_id), FGCM_EXACT, this->md5sum);
+			const GRFConfig *gc = FindGRFConfig(BSWAP32(this->unique_id), FGCM_EXACT, &this->md5sum);
 			tmp = gc != nullptr ? gc->filename.c_str() : nullptr;
 			break;
 		}
diff --git a/src/network/core/tcp_content_type.h b/src/network/core/tcp_content_type.h
--- a/src/network/core/tcp_content_type.h
+++ b/src/network/core/tcp_content_type.h
@@ -12,6 +12,8 @@
 #ifndef NETWORK_CORE_TCP_CONTENT_TYPE_H
 #define NETWORK_CORE_TCP_CONTENT_TYPE_H
 
+#include "../../3rdparty/md5/md5.h"
+
 /** The values in the enum are important; they are used as database 'keys' */
 enum ContentType {
 	CONTENT_TYPE_BEGIN         = 1, ///< Helper to mark the begin of the types
@@ -67,7 +69,7 @@ struct ContentInfo {
 	std::string url;                         ///< URL related to the content
 	std::string description;                 ///< Description of the content
 	uint32 unique_id = 0;                    ///< Unique ID; either GRF ID or shortname
-	byte md5sum[16] = {0};                   ///< The MD5 checksum
+	MD5Hash md5sum;                          ///< The MD5 checksum
 	std::vector<ContentID> dependencies;     ///< The dependencies (unique server side ids)
 	StringList tags;                         ///< Tags associated with the content
 	State state = State::UNSELECTED;         ///< Whether the content info is selected (for download)
diff --git a/src/network/network.cpp b/src/network/network.cpp
--- a/src/network/network.cpp
+++ b/src/network/network.cpp
@@ -190,18 +190,14 @@ std::string GenerateCompanyPasswordHash(
 	}
 
 	Md5 checksum;
-	uint8 digest[16];
+	MD5Hash digest;
 
 	/* Generate the MD5 hash */
 	std::string salted_password_string = salted_password.str();
 	checksum.Append(salted_password_string.data(), salted_password_string.size());
 	checksum.Finish(digest);
 
-	std::ostringstream hashed_password;
-	hashed_password << std::hex << std::setfill('0');
-	for (int di = 0; di < 16; di++) hashed_password << std::setw(2) << (int)digest[di]; // Cast needed, otherwise interpreted as character to add
-
-	return hashed_password.str();
+	return MD5SumToString(digest);
 }
 
 /**
diff --git a/src/network/network_client.cpp b/src/network/network_client.cpp
--- a/src/network/network_client.cpp
+++ b/src/network/network_client.cpp
@@ -322,7 +322,7 @@ std::string _network_server_name;
 NetworkJoinInfo _network_join;
 
 /** Make sure the server ID length is the same as a md5 hash. */
-static_assert(NETWORK_SERVER_ID_LENGTH == 16 * 2 + 1);
+static_assert(NETWORK_SERVER_ID_LENGTH == MD5_HASH_BYTES * 2 + 1);
 
 /***********
  * Sending functions
@@ -663,7 +663,7 @@ NetworkRecvStatus ClientNetworkGameSocke
 		DeserializeGRFIdentifier(p, &c);
 
 		/* Check whether we know this GRF */
-		const GRFConfig *f = FindGRFConfig(c.grfid, FGCM_EXACT, c.md5sum);
+		const GRFConfig *f = FindGRFConfig(c.grfid, FGCM_EXACT, &c.md5sum);
 		if (f == nullptr) {
 			/* We do not know this GRF, bail out of initialization */
 			Debug(grf, 0, "NewGRF {:08X} not found; checksum {}", BSWAP32(c.grfid), MD5SumToString(c.md5sum));
diff --git a/src/network/network_content.cpp b/src/network/network_content.cpp
--- a/src/network/network_content.cpp
+++ b/src/network/network_content.cpp
@@ -37,7 +37,7 @@ ClientNetworkContentSocketHandler _netwo
 /** Wrapper function for the HasProc */
 static bool HasGRFConfig(const ContentInfo *ci, bool md5sum)
 {
-	return FindGRFConfig(BSWAP32(ci->unique_id), md5sum ? FGCM_EXACT : FGCM_ANY, md5sum ? ci->md5sum : nullptr) != nullptr;
+	return FindGRFConfig(BSWAP32(ci->unique_id), md5sum ? FGCM_EXACT : FGCM_ANY, md5sum ? &ci->md5sum : nullptr) != nullptr;
 }
 
 /**
@@ -62,7 +62,7 @@ bool ClientNetworkContentSocketHandler::
 	ci->description = p->Recv_string(NETWORK_CONTENT_DESC_LENGTH, SVS_REPLACE_WITH_QUESTION_MARK | SVS_ALLOW_NEWLINE);
 
 	ci->unique_id = p->Recv_uint32();
-	for (uint j = 0; j < sizeof(ci->md5sum); j++) {
+	for (size_t j = 0; j < ci->md5sum.size(); j++) {
 		ci->md5sum[j] = p->Recv_uint8();
 	}
 
@@ -144,8 +144,7 @@ bool ClientNetworkContentSocketHandler::
 
 	/* Do we already have a stub for this? */
 	for (ContentInfo *ici : this->infos) {
-		if (ici->type == ci->type && ici->unique_id == ci->unique_id &&
-				memcmp(ci->md5sum, ici->md5sum, sizeof(ci->md5sum)) == 0) {
+		if (ici->type == ci->type && ici->unique_id == ci->unique_id && ci->md5sum == ici->md5sum) {
 			/* Preserve the name if possible */
 			if (ci->name.empty()) ci->name = ici->name;
 			if (ici->IsSelected()) ci->state = ici->state;
@@ -267,7 +266,7 @@ void ClientNetworkContentSocketHandler::
 
 	assert(cv->size() < 255);
 	assert(cv->size() < (TCP_MTU - sizeof(PacketSize) - sizeof(byte) - sizeof(uint8)) /
-			(sizeof(uint8) + sizeof(uint32) + (send_md5sum ? /*sizeof(ContentInfo::md5sum)*/16 : 0)));
+			(sizeof(uint8) + sizeof(uint32) + (send_md5sum ? MD5_HASH_BYTES : 0)));
 
 	Packet *p = new Packet(send_md5sum ? PACKET_CONTENT_CLIENT_INFO_EXTID_MD5 : PACKET_CONTENT_CLIENT_INFO_EXTID, TCP_MTU);
 	p->Send_uint8((uint8)cv->size());
@@ -277,7 +276,7 @@ void ClientNetworkContentSocketHandler::
 		p->Send_uint32(ci->unique_id);
 		if (!send_md5sum) continue;
 
-		for (uint j = 0; j < sizeof(ci->md5sum); j++) {
+		for (size_t j = 0; j < ci->md5sum.size(); j++) {
 			p->Send_uint8(ci->md5sum[j]);
 		}
 	}
@@ -288,7 +287,7 @@ void ClientNetworkContentSocketHandler::
 		bool found = false;
 		for (ContentInfo *ci2 : this->infos) {
 			if (ci->type == ci2->type && ci->unique_id == ci2->unique_id &&
-					(!send_md5sum || memcmp(ci->md5sum, ci2->md5sum, sizeof(ci->md5sum)) == 0)) {
+					(!send_md5sum || ci->md5sum == ci2->md5sum)) {
 				found = true;
 				break;
 			}
diff --git a/src/network/network_gamelist.cpp b/src/network/network_gamelist.cpp
--- a/src/network/network_gamelist.cpp
+++ b/src/network/network_gamelist.cpp
@@ -124,7 +124,7 @@ void NetworkAfterNewGRFScan()
 		for (GRFConfig *c = item->info.grfconfig; c != nullptr; c = c->next) {
 			assert(HasBit(c->flags, GCF_COPY));
 
-			const GRFConfig *f = FindGRFConfig(c->ident.grfid, FGCM_EXACT, c->ident.md5sum);
+			const GRFConfig *f = FindGRFConfig(c->ident.grfid, FGCM_EXACT, &c->ident.md5sum);
 			if (f == nullptr) {
 				/* Don't know the GRF (anymore), so mark game incompatible. */
 				c->status = GCS_NOT_FOUND;
diff --git a/src/newgrf_config.cpp b/src/newgrf_config.cpp
--- a/src/newgrf_config.cpp
+++ b/src/newgrf_config.cpp
@@ -46,6 +46,7 @@ GRFConfig::GRFConfig(const std::string &
 GRFConfig::GRFConfig(const GRFConfig &config) :
 	ZeroedMemoryAllocator(),
 	ident(config.ident),
+	original_md5sum(config.original_md5sum),
 	filename(config.filename),
 	name(config.name),
 	info(config.info),
@@ -61,7 +62,6 @@ GRFConfig::GRFConfig(const GRFConfig &co
 	param_info(config.param_info),
 	has_param_defaults(config.has_param_defaults)
 {
-	MemCpyT<uint8>(this->original_md5sum, config.original_md5sum, lengthof(this->original_md5sum));
 	MemCpyT<uint32>(this->param, config.param, lengthof(this->param));
 	if (config.error != nullptr) this->error = std::make_unique<GRFError>(*config.error);
 }
@@ -475,7 +475,7 @@ GRFListCompatibility IsGoodGRFConfigList
 	GRFListCompatibility res = GLC_ALL_GOOD;
 
 	for (GRFConfig *c = grfconfig; c != nullptr; c = c->next) {
-		const GRFConfig *f = FindGRFConfig(c->ident.grfid, FGCM_EXACT, c->ident.md5sum);
+		const GRFConfig *f = FindGRFConfig(c->ident.grfid, FGCM_EXACT, &c->ident.md5sum);
 		if (f == nullptr || HasBit(f->flags, GCF_INVALID)) {
 			/* If we have not found the exactly matching GRF try to find one with the
 			 * same grfid, as it most likely is compatible */
@@ -485,7 +485,7 @@ GRFListCompatibility IsGoodGRFConfigList
 				if (!HasBit(c->flags, GCF_COMPATIBLE)) {
 					/* Preserve original_md5sum after it has been assigned */
 					SetBit(c->flags, GCF_COMPATIBLE);
-					memcpy(c->original_md5sum, c->ident.md5sum, sizeof(c->original_md5sum));
+					c->original_md5sum = c->ident.md5sum;
 				}
 
 				/* Non-found has precedence over compatibility load */
@@ -508,7 +508,7 @@ compatible_grf:
 			 * already a local one, so there is no need to replace it. */
 			if (!HasBit(c->flags, GCF_COPY)) {
 				c->filename = f->filename;
-				memcpy(c->ident.md5sum, f->ident.md5sum, sizeof(c->ident.md5sum));
+				c->ident.md5sum = f->ident.md5sum;
 				c->name = f->name;
 				c->info = f->name;
 				c->error = nullptr;
@@ -575,7 +575,7 @@ bool GRFFileScanner::AddFile(const std::
 			GRFConfig **pd, *d;
 			bool stop = false;
 			for (pd = &_all_grfs; (d = *pd) != nullptr; pd = &d->next) {
-				if (c->ident.grfid == d->ident.grfid && memcmp(c->ident.md5sum, d->ident.md5sum, sizeof(c->ident.md5sum)) == 0) added = false;
+				if (c->ident.grfid == d->ident.grfid && c->ident.md5sum == d->ident.md5sum) added = false;
 				/* Because there can be multiple grfs with the same name, make sure we checked all grfs with the same name,
 				 *  before inserting the entry. So insert a new grf at the end of all grfs with the same name, instead of
 				 *  just after the first with the same name. Avoids doubles in the list. */
@@ -691,7 +691,7 @@ void ScanNewGRFFiles(NewGRFScanCallback 
  * @param desired_version Requested version
  * @return The matching grf, if it exists in #_all_grfs, else \c nullptr.
  */
-const GRFConfig *FindGRFConfig(uint32 grfid, FindGRFConfigMode mode, const uint8 *md5sum, uint32 desired_version)
+const GRFConfig *FindGRFConfig(uint32 grfid, FindGRFConfigMode mode, const MD5Hash *md5sum, uint32 desired_version)
 {
 	assert((mode == FGCM_EXACT) != (md5sum == nullptr));
 	const GRFConfig *best = nullptr;
diff --git a/src/newgrf_config.h b/src/newgrf_config.h
--- a/src/newgrf_config.h
+++ b/src/newgrf_config.h
@@ -16,6 +16,7 @@
 #include "fileio_type.h"
 #include "textfile_type.h"
 #include "newgrf_text.h"
+#include "3rdparty/md5/md5.h"
 
 /** GRF config bit flags */
 enum GCF_Flags {
@@ -81,15 +82,12 @@ enum GRFPalette {
 /** Basic data to distinguish a GRF. Used in the server list window */
 struct GRFIdentifier {
 	uint32 grfid;     ///< GRF ID (defined by Action 0x08)
-	uint8 md5sum[16]; ///< MD5 checksum of file to distinguish files with the same GRF ID (eg. newer version of GRF)
+	MD5Hash md5sum;   ///< MD5 checksum of file to distinguish files with the same GRF ID (eg. newer version of GRF)
 
 	GRFIdentifier() = default;
 	GRFIdentifier(const GRFIdentifier &other) = default;
 	GRFIdentifier(GRFIdentifier &&other) = default;
-	GRFIdentifier(uint32 grfid, const uint8 *md5sum) : grfid(grfid)
-	{
-		MemCpyT(this->md5sum, md5sum, lengthof(this->md5sum));
-	}
+	GRFIdentifier(uint32 grfid, const MD5Hash &md5sum) : grfid(grfid), md5sum(md5sum) {}
 
 	GRFIdentifier& operator =(const GRFIdentifier &other) = default;
 
@@ -99,11 +97,11 @@ struct GRFIdentifier {
 	 * @param md5sum Expected md5sum, may be \c nullptr (in which case, do not check it).
 	 * @return the object has the provided grfid and md5sum.
 	 */
-	inline bool HasGrfIdentifier(uint32 grfid, const uint8 *md5sum) const
+	inline bool HasGrfIdentifier(uint32 grfid, const MD5Hash *md5sum) const
 	{
 		if (this->grfid != grfid) return false;
 		if (md5sum == nullptr) return true;
-		return memcmp(md5sum, this->md5sum, sizeof(this->md5sum)) == 0;
+		return *md5sum == this->md5sum;
 	}
 };
 
@@ -158,7 +156,7 @@ struct GRFConfig : ZeroedMemoryAllocator
 	GRFConfig &operator=(GRFConfig &rhs) = delete;
 
 	GRFIdentifier ident; ///< grfid and md5sum to uniquely identify newgrfs
-	uint8 original_md5sum[16]; ///< MD5 checksum of original file if only a 'compatible' file was loaded
+	MD5Hash original_md5sum; ///< MD5 checksum of original file if only a 'compatible' file was loaded
 	std::string filename; ///< Filename - either with or without full path
 	GRFTextWrapper name; ///< NOSAVE: GRF name (Action 0x08)
 	GRFTextWrapper info; ///< NOSAVE: GRF info (author, copyright, ...) (Action 0x08)
@@ -217,7 +215,7 @@ struct NewGRFScanCallback {
 size_t GRFGetSizeOfDataSection(FILE *f);
 
 void ScanNewGRFFiles(NewGRFScanCallback *callback);
-const GRFConfig *FindGRFConfig(uint32 grfid, FindGRFConfigMode mode, const uint8 *md5sum = nullptr, uint32 desired_version = 0);
+const GRFConfig *FindGRFConfig(uint32 grfid, FindGRFConfigMode mode, const MD5Hash *md5sum = nullptr, uint32 desired_version = 0);
 GRFConfig *GetGRFConfig(uint32 grfid, uint32 mask = 0xFFFFFFFF);
 GRFConfig **CopyGRFConfigList(GRFConfig **dst, const GRFConfig *src, bool init_only);
 void AppendStaticGRFConfigs(GRFConfig **dst);
diff --git a/src/newgrf_gui.cpp b/src/newgrf_gui.cpp
--- a/src/newgrf_gui.cpp
+++ b/src/newgrf_gui.cpp
@@ -1245,7 +1245,7 @@ struct NewGRFWindow : public Window, New
 					bool compatible = HasBit(c->flags, GCF_COMPATIBLE);
 					if (c->status != GCS_NOT_FOUND && !compatible) continue;
 
-					const GRFConfig *f = FindGRFConfig(c->ident.grfid, FGCM_EXACT, compatible ? c->original_md5sum : c->ident.md5sum);
+					const GRFConfig *f = FindGRFConfig(c->ident.grfid, FGCM_EXACT, compatible ? &c->original_md5sum : &c->ident.md5sum);
 					if (f == nullptr || HasBit(f->flags, GCF_INVALID)) continue;
 
 					*l = new GRFConfig(*f);
@@ -1452,7 +1452,7 @@ private:
 		i = a->version - b->version;
 		if (i != 0) return i < 0;
 
-		return memcmp(a->ident.md5sum, b->ident.md5sum, lengthof(b->ident.md5sum)) < 0;
+		return a->ident.md5sum < b->ident.md5sum;
 	}
 
 	/** Filter grfs by tags/name */
@@ -1473,7 +1473,7 @@ private:
 
 		for (const GRFConfig *c = _all_grfs; c != nullptr; c = c->next) {
 			bool found = false;
-			for (const GRFConfig *grf = this->actives; grf != nullptr && !found; grf = grf->next) found = grf->ident.HasGrfIdentifier(c->ident.grfid, c->ident.md5sum);
+			for (const GRFConfig *grf = this->actives; grf != nullptr && !found; grf = grf->next) found = grf->ident.HasGrfIdentifier(c->ident.grfid, &c->ident.md5sum);
 			if (found) continue;
 
 			if (_settings_client.gui.newgrf_show_old_versions) {
@@ -1490,7 +1490,7 @@ private:
 				 * If we are the best version, then we definitely want to
 				 * show that NewGRF!.
 				 */
-				if (best->version == 0 || best->ident.HasGrfIdentifier(c->ident.grfid, c->ident.md5sum)) {
+				if (best->version == 0 || best->ident.HasGrfIdentifier(c->ident.grfid, &c->ident.md5sum)) {
 					this->avails.push_back(c);
 				}
 			}
@@ -1575,7 +1575,7 @@ void ShowMissingContentWindow(const GRFC
 		ci->state = ContentInfo::DOES_NOT_EXIST;
 		ci->name = c->GetName();
 		ci->unique_id = BSWAP32(c->ident.grfid);
-		memcpy(ci->md5sum, HasBit(c->flags, GCF_COMPATIBLE) ? c->original_md5sum : c->ident.md5sum, sizeof(ci->md5sum));
+		ci->md5sum = HasBit(c->flags, GCF_COMPATIBLE) ? c->original_md5sum : c->ident.md5sum;
 		cv.push_back(ci);
 	}
 	ShowNetworkContentListWindow(cv.size() == 0 ? nullptr : &cv, CONTENT_TYPE_NEWGRF);
diff --git a/src/script/script_scanner.cpp b/src/script/script_scanner.cpp
--- a/src/script/script_scanner.cpp
+++ b/src/script/script_scanner.cpp
@@ -154,18 +154,14 @@ std::string ScriptScanner::GetConsoleLis
 
 /** Helper for creating a MD5sum of all files within of a script. */
 struct ScriptFileChecksumCreator : FileScanner {
-	byte md5sum[16];  ///< The final md5sum.
+	MD5Hash md5sum; ///< The final md5sum.
 	Subdirectory dir; ///< The directory to look in.
 
 	/**
 	 * Initialise the md5sum to be all zeroes,
 	 * so we can easily xor the data.
 	 */
-	ScriptFileChecksumCreator(Subdirectory dir)
-	{
-		this->dir = dir;
-		memset(this->md5sum, 0, sizeof(this->md5sum));
-	}
+	ScriptFileChecksumCreator(Subdirectory dir) : dir(dir) {}
 
 	/* Add the file and calculate the md5 sum. */
 	virtual bool AddFile(const std::string &filename, size_t basepath_length, const std::string &tar_filename)
@@ -173,7 +169,6 @@ struct ScriptFileChecksumCreator : FileS
 		Md5 checksum;
 		uint8 buffer[1024];
 		size_t len, size;
-		byte tmp_md5sum[16];
 
 		/* Open the file ... */
 		FILE *f = FioFOpenFile(filename, "rb", this->dir, &size);
@@ -184,12 +179,14 @@ struct ScriptFileChecksumCreator : FileS
 			size -= len;
 			checksum.Append(buffer, len);
 		}
+
+		MD5Hash tmp_md5sum;
 		checksum.Finish(tmp_md5sum);
 
 		FioFCloseFile(f);
 
 		/* ... and xor it to the overall md5sum. */
-		for (uint i = 0; i < sizeof(md5sum); i++) this->md5sum[i] ^= tmp_md5sum[i];
+		this->md5sum ^= tmp_md5sum;
 
 		return true;
 	}
@@ -237,7 +234,7 @@ static bool IsSameScript(const ContentIn
 		checksum.Scan(".nut", path);
 	}
 
-	return memcmp(ci->md5sum, checksum.md5sum, sizeof(ci->md5sum)) == 0;
+	return ci->md5sum == checksum.md5sum;
 }
 
 bool ScriptScanner::HasScript(const ContentInfo *ci, bool md5sum)
diff --git a/src/settings.cpp b/src/settings.cpp
--- a/src/settings.cpp
+++ b/src/settings.cpp
@@ -969,7 +969,8 @@ static GRFConfig *GRFLoadConfig(IniFile 
 	for (item = group->item; item != nullptr; item = item->next) {
 		GRFConfig *c = nullptr;
 
-		uint8 grfid_buf[4], md5sum[16];
+		uint8 grfid_buf[4];
+		MD5Hash md5sum;
 		const char *filename = item->name.c_str();
 		bool has_grfid = false;
 		bool has_md5sum = false;
@@ -978,12 +979,12 @@ static GRFConfig *GRFLoadConfig(IniFile 
 		has_grfid = DecodeHexText(filename, grfid_buf, lengthof(grfid_buf));
 		if (has_grfid) {
 			filename += 1 + 2 * lengthof(grfid_buf);
-			has_md5sum = DecodeHexText(filename, md5sum, lengthof(md5sum));
-			if (has_md5sum) filename += 1 + 2 * lengthof(md5sum);
+			has_md5sum = DecodeHexText(filename, md5sum.data(), md5sum.size());
+			if (has_md5sum) filename += 1 + 2 * md5sum.size();
 
 			uint32 grfid = grfid_buf[0] | (grfid_buf[1] << 8) | (grfid_buf[2] << 16) | (grfid_buf[3] << 24);
 			if (has_md5sum) {
-				const GRFConfig *s = FindGRFConfig(grfid, FGCM_EXACT, md5sum);
+				const GRFConfig *s = FindGRFConfig(grfid, FGCM_EXACT, &md5sum);
 				if (s != nullptr) c = new GRFConfig(*s);
 			}
 			if (c == nullptr && !FioCheckFileExists(filename, NEWGRF_DIR)) {
diff --git a/src/string.cpp b/src/string.cpp
--- a/src/string.cpp
+++ b/src/string.cpp
@@ -618,9 +618,9 @@ int CDECL seprintf(char *str, const char
  * @param md5sum the md5sum itself
  * @return the string representation of the md5sum.
  */
-std::string MD5SumToString(const uint8 md5sum[16])
+std::string MD5SumToString(const MD5Hash &md5sum)
 {
-	return FormatArrayAsHex({md5sum, 16});
+	return FormatArrayAsHex(md5sum);
 }
 
 
diff --git a/src/string_func.h b/src/string_func.h
--- a/src/string_func.h
+++ b/src/string_func.h
@@ -29,6 +29,7 @@
 #include "core/bitmath_func.hpp"
 #include "core/span_type.hpp"
 #include "string_type.h"
+#include "3rdparty/md5/md5.h"
 
 char *strecat(char *dst, const char *src, const char *last) NOACCESS(3);
 char *strecpy(char *dst, const char *src, const char *last) NOACCESS(3);
@@ -90,7 +91,7 @@ static inline size_t ttd_strnlen(const c
 	return t - str;
 }
 
-std::string MD5SumToString(const uint8 md5sum[16]);
+std::string MD5SumToString(const MD5Hash &md5sum);
 
 bool IsValidChar(WChar key, CharSetFilter afilter);