diff --git a/src/bench/base58.cpp b/src/bench/base58.cpp
index 3319c179bf5..70850fe74fb 100644
--- a/src/bench/base58.cpp
+++ b/src/bench/base58.cpp
@@ -7,20 +7,22 @@
 #include "validation.h"
 #include "base58.h"
 
+#include <array>
 #include <vector>
 #include <string>
 
 
 static void Base58Encode(benchmark::State& state)
 {
-    unsigned char buff[32] = {
-        17, 79, 8, 99, 150, 189, 208, 162, 22, 23, 203, 163, 36, 58, 147,
-        227, 139, 2, 215, 100, 91, 38, 11, 141, 253, 40, 117, 21, 16, 90,
-        200, 24
+    static const std::array<unsigned char, 32> buff = {
+        {
+            17, 79, 8, 99, 150, 189, 208, 162, 22, 23, 203, 163, 36, 58, 147,
+            227, 139, 2, 215, 100, 91, 38, 11, 141, 253, 40, 117, 21, 16, 90,
+            200, 24
+        }
     };
-    unsigned char* b = buff;
     while (state.KeepRunning()) {
-        EncodeBase58(b, b + 32);
+        EncodeBase58(buff.data(), buff.data() + buff.size());
     }
 }
 
diff --git a/src/bench/checkqueue.cpp b/src/bench/checkqueue.cpp
index 88a2a570f93..79082290e25 100644
--- a/src/bench/checkqueue.cpp
+++ b/src/bench/checkqueue.cpp
@@ -19,7 +19,7 @@ static const int MIN_CORES = 2;
 static const size_t BATCHES = 101;
 static const size_t BATCH_SIZE = 30;
 static const int PREVECTOR_SIZE = 28;
-static const int QUEUE_BATCH_SIZE = 128;
+static const unsigned int QUEUE_BATCH_SIZE = 128;
 static void CCheckQueueSpeed(benchmark::State& state)
 {
     struct FakeJobNoWork {
diff --git a/src/chainparams.cpp b/src/chainparams.cpp
index 5f8ebaa7af1..3991e245e6f 100644
--- a/src/chainparams.cpp
+++ b/src/chainparams.cpp
@@ -459,8 +459,9 @@ class CRegTestParams : public CChainParams {
         fMineBlocksOnDemand = true;
 
         checkpointData = (CCheckpointData){
-            boost::assign::map_list_of
-            ( 0, uint256S("0x3d2160a3b5dc4a9d62e7e66a295f70313ac808440ef7400d6c0772171ce973a5"))
+            {
+                {0, uint256S("0x3d2160a3b5dc4a9d62e7e66a295f70313ac808440ef7400d6c0772171ce973a5")},
+            }
         };
 
         chainTxData = ChainTxData{
diff --git a/src/compat.h b/src/compat.h
index d4dc3ba9923..6a2cbc5dcb1 100644
--- a/src/compat.h
+++ b/src/compat.h
@@ -32,6 +32,7 @@
 #include <mswsock.h>
 #include <windows.h>
 #include <ws2tcpip.h>
+#include <stdint.h>
 #else
 #include <sys/fcntl.h>
 #include <sys/mman.h>
@@ -74,6 +75,15 @@ typedef u_int SOCKET;
 #else
 #define MAX_PATH            1024
 #endif
+#ifdef _MSC_VER
+#if !defined(ssize_t)
+#ifdef _WIN64
+typedef int64_t ssize_t;
+#else
+typedef int32_t ssize_t;
+#endif
+#endif
+#endif
 
 // As Solaris does not have the MSG_NOSIGNAL flag for send(2) syscall, it is defined as 0
 #if !defined(HAVE_MSG_NOSIGNAL) && !defined(MSG_NOSIGNAL)
diff --git a/src/random.h b/src/random.h
index b35cf51a166..6503d8359f0 100644
--- a/src/random.h
+++ b/src/random.h
@@ -121,7 +121,7 @@ class FastRandomContext {
  * sure that the underlying OS APIs for all platforms support the number.
  * (many cap out at 256 bytes).
  */
-static const ssize_t NUM_OS_RANDOM_BYTES = 32;
+static const int NUM_OS_RANDOM_BYTES = 32;
 
 /** Get 32 bytes of system entropy. Do not use this in application code: use
  * GetStrongRandBytes instead.
diff --git a/src/support/cleanse.cpp b/src/support/cleanse.cpp
index a2141b24498..eb6e0a73a20 100644
--- a/src/support/cleanse.cpp
+++ b/src/support/cleanse.cpp
@@ -5,9 +5,39 @@
 
 #include "cleanse.h"
 
-#include <openssl/crypto.h>
+#include <cstring>
 
+#if defined(_MSC_VER)
+#include <Windows.h> // For SecureZeroMemory.
+#endif
+
+/* Compilers have a bad habit of removing "superfluous" memset calls that
+ * are trying to zero memory. For example, when memset()ing a buffer and
+ * then free()ing it, the compiler might decide that the memset is
+ * unobservable and thus can be removed.
+ *
+ * Previously we used OpenSSL which tried to stop this by a) implementing
+ * memset in assembly on x86 and b) putting the function in its own file
+ * for other platforms.
+ *
+ * This change removes those tricks in favour of using asm directives to
+ * scare the compiler away. As best as our compiler folks can tell, this is
+ * sufficient and will continue to be so.
+ *
+ * Adam Langley <agl@google.com>
+ * Commit: ad1907fe73334d6c696c8539646c21b11178f20f
+ * BoringSSL (LICENSE: ISC)
+ */
 void memory_cleanse(void *ptr, size_t len)
 {
-    OPENSSL_cleanse(ptr, len);
+    std::memset(ptr, 0, len);
+
+    /* As best as we can tell, this is sufficient to break any optimisations that
+       might try to eliminate "superfluous" memsets. If there's an easy way to
+       detect memset_s, it would be better to use that. */
+#if defined(_MSC_VER)
+    SecureZeroMemory(ptr, len);
+#else
+    __asm__ __volatile__("" : : "r"(ptr) : "memory");
+#endif
 }
diff --git a/src/test/checkqueue_tests.cpp b/src/test/checkqueue_tests.cpp
index 36b8768cd36..34d9bdb6348 100644
--- a/src/test/checkqueue_tests.cpp
+++ b/src/test/checkqueue_tests.cpp
@@ -24,7 +24,7 @@
 // otherwise.
 BOOST_FIXTURE_TEST_SUITE(checkqueue_tests, TestingSetup)
 
-static const int QUEUE_BATCH_SIZE = 128;
+static const unsigned int QUEUE_BATCH_SIZE = 128;
 
 struct FakeCheck {
     bool operator()()