diff --git a/configure b/configure
index 3d0e701c745..3c19e7e60ec 100755
--- a/configure
+++ b/configure
@@ -15927,6 +15927,16 @@ fi
 cat >>confdefs.h <<_ACEOF
 #define HAVE_DECL_STRSEP $ac_have_decl
 _ACEOF
+ac_fn_c_check_decl "$LINENO" "timingsafe_bcmp" "ac_cv_have_decl_timingsafe_bcmp" "$ac_includes_default"
+if test "x$ac_cv_have_decl_timingsafe_bcmp" = xyes; then :
+  ac_have_decl=1
+else
+  ac_have_decl=0
+fi
+
+cat >>confdefs.h <<_ACEOF
+#define HAVE_DECL_TIMINGSAFE_BCMP $ac_have_decl
+_ACEOF
 
 
 # We can't use AC_CHECK_FUNCS to detect these functions, because it
@@ -16099,6 +16109,19 @@ esac
 
 fi
 
+ac_fn_c_check_func "$LINENO" "timingsafe_bcmp" "ac_cv_func_timingsafe_bcmp"
+if test "x$ac_cv_func_timingsafe_bcmp" = xyes; then :
+  $as_echo "#define HAVE_TIMINGSAFE_BCMP 1" >>confdefs.h
+
+else
+  case " $LIBOBJS " in
+  *" timingsafe_bcmp.$ac_objext "* ) ;;
+  *) LIBOBJS="$LIBOBJS timingsafe_bcmp.$ac_objext"
+ ;;
+esac
+
+fi
+
 
 
 ac_fn_c_check_func "$LINENO" "pthread_barrier_wait" "ac_cv_func_pthread_barrier_wait"
diff --git a/configure.ac b/configure.ac
index 47a287926bc..65db0673f8a 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1805,7 +1805,7 @@ AC_CHECK_DECLS(posix_fadvise, [], [], [#include <fcntl.h>])
 ]) # fi
 
 AC_CHECK_DECLS(fdatasync, [], [], [#include <unistd.h>])
-AC_CHECK_DECLS([strlcat, strlcpy, strnlen, strsep])
+AC_CHECK_DECLS([strlcat, strlcpy, strnlen, strsep, timingsafe_bcmp])
 
 # We can't use AC_CHECK_FUNCS to detect these functions, because it
 # won't handle deployment target restrictions on macOS
@@ -1826,6 +1826,7 @@ AC_REPLACE_FUNCS(m4_normalize([
 	strlcpy
 	strnlen
 	strsep
+	timingsafe_bcmp
 ]))
 
 AC_REPLACE_FUNCS(pthread_barrier_wait)
diff --git a/meson.build b/meson.build
index ba7916d1493..e8b872d29ad 100644
--- a/meson.build
+++ b/meson.build
@@ -2569,6 +2569,7 @@ decl_checks = [
   ['strlcpy', 'string.h'],
   ['strnlen', 'string.h'],
   ['strsep',  'string.h'],
+  ['timingsafe_bcmp',  'string.h'],
 ]
 
 # Need to check for function declarations for these functions, because
@@ -2826,6 +2827,7 @@ func_checks = [
   ['strsignal'],
   ['sync_file_range'],
   ['syncfs'],
+  ['timingsafe_bcmp'],
   ['uselocale'],
   ['wcstombs_l'],
 ]
diff --git a/src/include/port.h b/src/include/port.h
index 3faae03d246..3964d3b1293 100644
--- a/src/include/port.h
+++ b/src/include/port.h
@@ -464,6 +464,10 @@ extern size_t strnlen(const char *str, size_t maxlen);
 extern char *strsep(char **stringp, const char *delim);
 #endif
 
+#if !HAVE_DECL_TIMINGSAFE_BCMP
+extern int	timingsafe_bcmp(const void *b1, const void *b2, size_t len);
+#endif
+
 /*
  * Callers should use the qsort() macro defined below instead of calling
  * pg_qsort() directly.
diff --git a/src/port/meson.build b/src/port/meson.build
index cf7f07644b9..51041e75609 100644
--- a/src/port/meson.build
+++ b/src/port/meson.build
@@ -73,6 +73,7 @@ replace_funcs_neg = [
   ['strlcpy'],
   ['strnlen'],
   ['strsep'],
+  ['timingsafe_bcmp'],
 ]
 
 if host_system != 'windows'
diff --git a/src/port/timingsafe_bcmp.c b/src/port/timingsafe_bcmp.c
new file mode 100644
index 00000000000..288865f50d1
--- /dev/null
+++ b/src/port/timingsafe_bcmp.c
@@ -0,0 +1,43 @@
+/*
+ * src/port/timingsafe_bcmp.c
+ *
+ *	$OpenBSD: timingsafe_bcmp.c,v 1.3 2015/08/31 02:53:57 guenther Exp $
+ */
+
+/*
+ * Copyright (c) 2010 Damien Miller.  All rights reserved.
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include "c.h"
+
+#ifdef USE_SSL
+#include <openssl/crypto.h>
+#endif
+
+int
+timingsafe_bcmp(const void *b1, const void *b2, size_t n)
+{
+#ifdef USE_SSL
+	return CRYPTO_memcmp(b1, b2, n);
+#else
+	const unsigned char *p1 = b1,
+			   *p2 = b2;
+	int			ret = 0;
+
+	for (; n > 0; n--)
+		ret |= *p1++ ^ *p2++;
+	return (ret != 0);
+#endif
+}