diff --git a/CHANGES b/CHANGES
index 28f32d6397..3a6575fb28 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1,3 +1,10 @@
+5264.	[func]		New DNS Cookie algorithm - siphash24 - has been added to
+			BIND 9. [GL #605]
+
+5236.	[func]		Add SipHash 2-4 implementation in lib/isc/siphash.c
+			and switch isc_hash_function() to use SipHash 2-4.
+			[GL #605]
+
 	--- 9.14.4 released ---
 
 5260.	[bug]		dnstap-read was producing malformed output for large
diff --git a/bin/named/named.conf.docbook b/bin/named/named.conf.docbook
index 3683f3ee18..5f7dd754a5 100644
--- a/bin/named/named.conf.docbook
+++ b/bin/named/named.conf.docbook
@@ -221,7 +221,7 @@ options {
 	check-wildcard <replaceable>boolean</replaceable>;
 	cleaning-interval <replaceable>integer</replaceable>;
 	clients-per-query <replaceable>integer</replaceable>;
-	cookie-algorithm ( aes | sha1 | sha256 );
+	cookie-algorithm ( aes | sha1 | sha256 | siphash24 );
 	cookie-secret <replaceable>string</replaceable>;
 	coresize ( default | unlimited | <replaceable>sizeval</replaceable> );
 	datasize ( default | unlimited | <replaceable>sizeval</replaceable> );
diff --git a/bin/named/server.c b/bin/named/server.c
index b3adb4d314..a572f7a0da 100644
--- a/bin/named/server.c
+++ b/bin/named/server.c
@@ -41,6 +41,7 @@
 #include <isc/print.h>
 #include <isc/refcount.h>
 #include <isc/resource.h>
+#include <isc/siphash.h>
 #include <isc/socket.h>
 #include <isc/stat.h>
 #include <isc/stats.h>
@@ -9150,7 +9151,9 @@ load_configuration(const char *filename, named_server_t *server,
 	obj = NULL;
 	result = named_config_get(maps, "cookie-algorithm", &obj);
 	INSIST(result == ISC_R_SUCCESS);
-	if (strcasecmp(cfg_obj_asstring(obj), "aes") == 0) {
+	if (strcasecmp(cfg_obj_asstring(obj), "siphash24") == 0) {
+		server->sctx->cookiealg = ns_cookiealg_siphash24;
+	} else if (strcasecmp(cfg_obj_asstring(obj), "aes") == 0) {
 		server->sctx->cookiealg = ns_cookiealg_aes;
 	} else if (strcasecmp(cfg_obj_asstring(obj), "sha1") == 0) {
 		server->sctx->cookiealg = ns_cookiealg_sha1;
@@ -9213,12 +9216,18 @@ load_configuration(const char *filename, named_server_t *server,
 
 			usedlength = isc_buffer_usedlength(&b);
 			switch (server->sctx->cookiealg) {
+			case ns_cookiealg_siphash24:
+				expectedlength = ISC_SIPHASH24_KEY_LENGTH;
+				if (usedlength != expectedlength) {
+					CHECKM(ISC_R_RANGE,
+					       "SipHash-2-4 cookie-secret must be 128 bits");
+				}
+				break;
 			case ns_cookiealg_aes:
 				expectedlength = ISC_AES128_KEYLENGTH;
 				if (usedlength != expectedlength) {
 					CHECKM(ISC_R_RANGE,
-					       "AES cookie-secret must be "
-					       "128 bits");
+					       "AES cookie-secret must be 128 bits");
 				}
 				break;
 			case ns_cookiealg_sha1:
diff --git a/bin/tests/system/cookie/bad-cookie-badaes.conf b/bin/tests/system/cookie/bad-cookie-badaes.conf
new file mode 100644
index 0000000000..6c8e42cabd
--- /dev/null
+++ b/bin/tests/system/cookie/bad-cookie-badaes.conf
@@ -0,0 +1,15 @@
+/*
+ * Copyright (C) Internet Systems Consortium, Inc. ("ISC")
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * See the COPYRIGHT file distributed with this work for additional
+ * information regarding copyright ownership.
+ */
+
+options {
+	cookie-algorithm aes;
+	cookie-secret "ebc7701beabb4a40c57d140eeb6733faaa";  // 136 bits
+};
diff --git a/bin/tests/system/cookie/bad-cookie-badsiphash24.conf b/bin/tests/system/cookie/bad-cookie-badsiphash24.conf
new file mode 100644
index 0000000000..392cb04473
--- /dev/null
+++ b/bin/tests/system/cookie/bad-cookie-badsiphash24.conf
@@ -0,0 +1,15 @@
+/*
+ * Copyright (C) Internet Systems Consortium, Inc. ("ISC")
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * See the COPYRIGHT file distributed with this work for additional
+ * information regarding copyright ownership.
+ */
+
+options {
+	cookie-algorithm siphash24;
+	cookie-secret "ebc7701beabb4a40c57d140eeb6733faaabbccdd";  // 160 bits
+};
diff --git a/bin/tests/system/cookie/good-cookie-aes.conf b/bin/tests/system/cookie/good-cookie-aes.conf
new file mode 100644
index 0000000000..efb56a67a4
--- /dev/null
+++ b/bin/tests/system/cookie/good-cookie-aes.conf
@@ -0,0 +1,15 @@
+/*
+ * Copyright (C) Internet Systems Consortium, Inc. ("ISC")
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * See the COPYRIGHT file distributed with this work for additional
+ * information regarding copyright ownership.
+ */
+
+options {
+	cookie-algorithm aes;
+	cookie-secret "ebc7701beabb4a40c57d140eeb6733fa";  // 128 bits
+};
diff --git a/bin/tests/system/cookie/good-cookie-siphash24.conf b/bin/tests/system/cookie/good-cookie-siphash24.conf
new file mode 100644
index 0000000000..2e2f628543
--- /dev/null
+++ b/bin/tests/system/cookie/good-cookie-siphash24.conf
@@ -0,0 +1,15 @@
+/*
+ * Copyright (C) Internet Systems Consortium, Inc. ("ISC")
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * See the COPYRIGHT file distributed with this work for additional
+ * information regarding copyright ownership.
+ */
+
+options {
+	cookie-algorithm siphash24;
+	cookie-secret "ebc7701beabb4a40c57d140eeb6733fa";  // 128 bits
+};
diff --git a/bin/tests/system/cookie/ns4/named.conf.in b/bin/tests/system/cookie/ns4/named.conf.in
index 79d1cda568..7ed0760f17 100644
--- a/bin/tests/system/cookie/ns4/named.conf.in
+++ b/bin/tests/system/cookie/ns4/named.conf.in
@@ -28,8 +28,8 @@ options {
 	listen-on-v6 { none; };
 	recursion yes;
 	dnssec-validation yes;
-	cookie-algorithm sha1;
-	cookie-secret "569d36a6cc27d6bf55502183302ba352745255a2";
+	cookie-algorithm siphash24;
+	cookie-secret "569d36a6cc27d6bf55502183302ba352";
 	require-server-cookie yes;
 };
 
diff --git a/bin/tests/system/cookie/ns5/named.conf.in b/bin/tests/system/cookie/ns5/named.conf.in
index ae51a9071d..7dd681b7f3 100644
--- a/bin/tests/system/cookie/ns5/named.conf.in
+++ b/bin/tests/system/cookie/ns5/named.conf.in
@@ -28,9 +28,9 @@ options {
 	listen-on-v6 { none; };
 	recursion yes;
 	dnssec-validation yes;
-	cookie-algorithm sha1;
-	cookie-secret "569d36a6cc27d6bf55502183302ba352745255a2";
-	cookie-secret "6b300e27a0db46d4b046e4189790fa7db3c1ffb3";
+	cookie-algorithm siphash24;
+	cookie-secret "569d36a6cc27d6bf55502183302ba352";
+	cookie-secret "6b300e27a0db46d4b046e4189790fa7d";
 	require-server-cookie yes;
 };
 
diff --git a/bin/tests/system/cookie/ns6/named.conf.in b/bin/tests/system/cookie/ns6/named.conf.in
index 368d9a3192..2cfd462d22 100644
--- a/bin/tests/system/cookie/ns6/named.conf.in
+++ b/bin/tests/system/cookie/ns6/named.conf.in
@@ -28,8 +28,8 @@ options {
 	listen-on-v6 { none; };
 	recursion yes;
 	dnssec-validation yes;
-	cookie-algorithm sha1;
-	cookie-secret "6b300e27a0db46d4b046e4189790fa7db3c1ffb3";
+	cookie-algorithm siphash24;
+	cookie-secret "6b300e27a0db46d4b046e4189790fa7d";
 	require-server-cookie yes;
 };
 
diff --git a/bin/tests/system/cookie/tests.sh b/bin/tests/system/cookie/tests.sh
index 0c4d25a77a..f82bb00546 100755
--- a/bin/tests/system/cookie/tests.sh
+++ b/bin/tests/system/cookie/tests.sh
@@ -211,12 +211,12 @@ status=`expr $status + $ret`
 #
 # Test shared cookie-secret support.
 #
-# NS4 has cookie-secret "569d36a6cc27d6bf55502183302ba352745255a2";
+# NS4 has cookie-secret "569d36a6cc27d6bf55502183302ba352";
 #
-# NS5 has cookie-secret "569d36a6cc27d6bf55502183302ba352745255a2";
-# NS5 has cookie-secret "6b300e27a0db46d4b046e4189790fa7db3c1ffb3"; (alternate)
+# NS5 has cookie-secret "569d36a6cc27d6bf55502183302ba352";
+# NS5 has cookie-secret "6b300e27a0db46d4b046e4189790fa7d"; (alternate)
 #
-# NS6 has cookie-secret "6b300e27a0db46d4b046e4189790fa7db3c1ffb3";
+# NS6 has cookie-secret "6b300e27a0db46d4b046e4189790fa7d";
 #
 # Server cookies from NS4 are accepted by NS5 and not NS6
 # Server cookies from NS5 are accepted by NS4 and not NS6
diff --git a/bin/tests/system/dyndb/driver/driver.c b/bin/tests/system/dyndb/driver/driver.c
index 26005de0e1..4d00dc2c7f 100644
--- a/bin/tests/system/dyndb/driver/driver.c
+++ b/bin/tests/system/dyndb/driver/driver.c
@@ -80,10 +80,9 @@ dyndb_init(isc_mem_t *mctx, const char *name, const char *parameters,
 		isc_lib_register();
 		isc_log_setcontext(dctx->lctx);
 		dns_log_setcontext(dctx->lctx);
+		isc_hash_set_initializer(dctx->hashinit);
 	}
 
-	isc_hash_set_initializer(dctx->hashinit);
-
 	s = isc_mem_strdup(mctx, parameters);
 	if (s == NULL) {
 		result = ISC_R_NOMEMORY;
diff --git a/bin/tests/system/ifconfig.sh b/bin/tests/system/ifconfig.sh
index aedb35fd0c..41b0182f80 100755
--- a/bin/tests/system/ifconfig.sh
+++ b/bin/tests/system/ifconfig.sh
@@ -105,13 +105,7 @@ case "$1" in
 				[ "$ipv6" ] && ifconfig lo0 inet6 \
 					fd92:7065:b8e:${ipv6}ff::$ns alias
 				;;
-			    *-unknown-netbsd*)
-				ifconfig lo0 10.53.$i.$ns alias \
-					netmask 255.255.255.0
-				[ "$ipv6" ] && ifconfig lo0 inet6 \
-					fd92:7065:b8e:${ipv6}ff::$ns alias
-				;;
-			    *-unknown-openbsd*)
+			    *-unknown-dragonfly*|*-unknown-netbsd*|*-unknown-openbsd*)
 				ifconfig lo0 10.53.$i.$ns alias \
 					netmask 255.255.255.0
 				[ "$ipv6" ] && ifconfig lo0 inet6 \
diff --git a/config.h.in b/config.h.in
index ae89d7f9c9..00a1d747b4 100644
--- a/config.h.in
+++ b/config.h.in
@@ -3,9 +3,6 @@
 /* Define if building universal (internal helper macro) */
 #undef AC_APPLE_UNIVERSAL_BUILD
 
-/* Use AES for Client Cookie generation */
-#undef AES_CC
-
 /* Define if you cannot bind() before connect() for TCP sockets. */
 #undef BROKEN_TCP_BIND_BEFORE_CONNECT
 
@@ -477,12 +474,6 @@
 /* Define if __thread keyword is available */
 #undef HAVE___THREAD
 
-/* Use HMAC-SHA1 for Client Cookie generation */
-#undef HMAC_SHA1_CC
-
-/* Use HMAC-SHA256 for Client Cookie generation */
-#undef HMAC_SHA256_CC
-
 /* Define if you want to use inline buffers */
 #undef ISC_BUFFER_USEINLINE
 
diff --git a/config.h.win32 b/config.h.win32
index fdbe44a07a..1930a2171f 100644
--- a/config.h.win32
+++ b/config.h.win32
@@ -298,15 +298,6 @@ typedef __int64 off_t;
 /* HMAC_*() return ints */
 @HMAC_RETURN_INT@
 
-/* Use AES for Client Cookie generation */
-@AES_CC@
-
-/* Use HMAC-SHA1 for Client Cookie generation */
-@HMAC_SHA1_CC@
-
-/* Use HMAC-SHA256 for Client Cookie generation */
-@HMAC_SHA256_CC@
-
 /* Define to 1 if you have the `readline' function. */
 @HAVE_READLINE@
 
diff --git a/configure b/configure
index 286f589167..4709dee5ac 100755
--- a/configure
+++ b/configure
@@ -1644,8 +1644,7 @@ Optional Packages:
   --with-locktype=ARG     Specify mutex lock type (adaptive or standard)
   --with-libtool          use GNU libtool
   --with-openssl=DIR      root of the OpenSSL directory
-  --with-cc-alg=ALG       choose the algorithm for Client Cookie
-                          [aes|sha1|sha256] (default is aes)
+  --with-cc-alg=ALG       deprecated
   --with-pkcs11=PATH      Build with PKCS11 support [no|path] (PATH is for the
                           PKCS11 provider)
   --with-gssapi=PATH|/path/krb5-config
@@ -16348,36 +16347,18 @@ LDFLAGS="$save_LDFLAGS"
 if test "${with_cc_alg+set}" = set; then :
   withval=$with_cc_alg; :
 else
-  with_cc_alg="aes"
+  with_cc_alg="siphash24"
 fi
 
 
-{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for the algorithm for Client Cookie" >&5
-$as_echo_n "checking for the algorithm for Client Cookie... " >&6; }
 case $with_cc_alg in #(
-  sha1|SHA1) :
-    { $as_echo "$as_me:${as_lineno-$LINENO}: result: sha1" >&5
-$as_echo "sha1" >&6; }
-
-$as_echo "#define HMAC_SHA1_CC 1" >>confdefs.h
- ;; #(
-  sha256|SHA256) :
-    { $as_echo "$as_me:${as_lineno-$LINENO}: result: sha256" >&5
-$as_echo "sha256" >&6; }
-
-$as_echo "#define HMAC_SHA256_CC 1" >>confdefs.h
- ;; #(
-  aes|AES|auto) :
-    { $as_echo "$as_me:${as_lineno-$LINENO}: result: aes" >&5
-$as_echo "aes" >&6; }
-
-$as_echo "#define AES_CC 1" >>confdefs.h
- ;; #(
+  siphash24) :
+    : ;; #(
   *) :
-    as_fn_error $? "Invalid $with_cc_alg algorithm for Client Cookie" "$LINENO" 5 ;;
+    { $as_echo "$as_me:${as_lineno-$LINENO}: WARNING: The Client Cookie is always SipHash 2-4 based" >&5
+$as_echo "$as_me: WARNING: The Client Cookie is always SipHash 2-4 based" >&2;} ;;
 esac
 
-
 PKCS11_TOOLS=
 PKCS11_TEST=
 #
diff --git a/configure.ac b/configure.ac
index dc5f8001dd..e8d2827c7c 100644
--- a/configure.ac
+++ b/configure.ac
@@ -917,21 +917,12 @@ AC_SUBST([OPENSSL_LDFLAGS])
 # Client Cookie algorithm choice
 #
 AC_ARG_WITH([cc-alg],
-	    [AS_HELP_STRING([--with-cc-alg=ALG],
-			   [choose the algorithm for Client Cookie
-			    [aes|sha1|sha256] (default is aes)])],
-	    [:], [with_cc_alg="aes"])
+	    [AS_HELP_STRING([--with-cc-alg=ALG], [deprecated])],
+	    [:], [with_cc_alg="siphash24"])
 
-AC_MSG_CHECKING([for the algorithm for Client Cookie])
 AS_CASE([$with_cc_alg],
-	[sha1|SHA1],[AC_MSG_RESULT([sha1])
-		     AC_DEFINE([HMAC_SHA1_CC], [1], [Use HMAC-SHA1 for Client Cookie generation])],
-	[sha256|SHA256],[AC_MSG_RESULT([sha256])
-			 AC_DEFINE([HMAC_SHA256_CC], [1], [Use HMAC-SHA256 for Client Cookie generation])],
-	[aes|AES|auto],[AC_MSG_RESULT([aes])
-		       AC_DEFINE([AES_CC], [1], [Use AES for Client Cookie generation])],
-	[AC_MSG_ERROR([Invalid $with_cc_alg algorithm for Client Cookie])])
-
+	[siphash24],[:],
+	[AC_MSG_WARN([The Client Cookie is always SipHash 2-4 based])])
 
 PKCS11_TOOLS=
 PKCS11_TEST=
diff --git a/doc/arm/notes.xml b/doc/arm/notes.xml
index 03653ec363..9f5ba91667 100644
--- a/doc/arm/notes.xml
+++ b/doc/arm/notes.xml
@@ -142,6 +142,18 @@
 	  as a result of a zone update.  [GL #513]
 	</para>
       </listitem>
+      <listitem>
+	<para>
+	  A SipHash 2-4 based DNS Cookie (RFC 7873) algorithm has been added.
+	</para>
+	<para>
+	  If you are running multiple DNS Servers (different versions of BIND 9
+	  or DNS server from multiple vendors) responding from the same IP
+	  address (anycast or load-balancing scenarios), you'll have to make
+	  sure that all the servers are configured with the same DNS Cookie
+	  algorithm and same Server Secret for the best performance.
+	</para>
+      </listitem>
     </itemizedlist>
   </section>
 
diff --git a/doc/misc/options b/doc/misc/options
index c692ed2ec9..7d9ca31cf2 100644
--- a/doc/misc/options
+++ b/doc/misc/options
@@ -107,7 +107,7 @@ options {
         check-wildcard <boolean>;
         cleaning-interval <integer>;
         clients-per-query <integer>;
-        cookie-algorithm ( aes | sha1 | sha256 );
+        cookie-algorithm ( aes | sha1 | sha256 | siphash24 );
         cookie-secret <string>; // may occur multiple times
         coresize ( default | unlimited | <sizeval> );
         datasize ( default | unlimited | <sizeval> );
diff --git a/lib/bind9/check.c b/lib/bind9/check.c
index 5ac9a81837..df3cbf1c02 100644
--- a/lib/bind9/check.c
+++ b/lib/bind9/check.c
@@ -31,6 +31,7 @@
 #include <isc/print.h>
 #include <isc/region.h>
 #include <isc/result.h>
+#include <isc/siphash.h>
 #include <isc/sockaddr.h>
 #include <isc/string.h>
 #include <isc/symtab.h>
@@ -859,7 +860,7 @@ check_options(const cfg_obj_t *options, isc_log_t *logctx, isc_mem_t *mctx,
 	dns_name_t *name;
 	isc_buffer_t b;
 	uint32_t lifetime = 3600;
-	const char *ccalg = "aes";
+	const char *ccalg = "siphash24";
 
 	/*
 	 * { "name", scale, value }
@@ -1353,8 +1354,14 @@ check_options(const cfg_obj_t *options, isc_log_t *logctx, isc_mem_t *mctx,
 			if (strcasecmp(ccalg, "aes") == 0 &&
 			    usedlength != ISC_AES128_KEYLENGTH) {
 				cfg_obj_log(obj, logctx, ISC_LOG_ERROR,
-					    "AES cookie-secret must be "
-					    "128 bits");
+					    "AES cookie-secret must be 128 bits");
+				if (result == ISC_R_SUCCESS)
+					result = ISC_R_RANGE;
+			}
+			if (strcasecmp(ccalg, "siphash24") == 0 &&
+			    usedlength != ISC_SIPHASH24_KEY_LENGTH) {
+				cfg_obj_log(obj, logctx, ISC_LOG_ERROR,
+					    "SipHash-2-4 cookie-secret must be 128 bits");
 				if (result == ISC_R_SUCCESS)
 					result = ISC_R_RANGE;
 			}
diff --git a/lib/dns/name.c b/lib/dns/name.c
index 9b704c75b5..afc81d07a4 100644
--- a/lib/dns/name.c
+++ b/lib/dns/name.c
@@ -458,15 +458,16 @@ dns_name_hash(const dns_name_t *name, bool case_sensitive) {
 	 */
 	REQUIRE(VALID_NAME(name));
 
-	if (name->labels == 0)
+	if (name->labels == 0) {
 		return (0);
+	}
 
 	length = name->length;
-	if (length > 16)
+	if (length > 16) {
 		length = 16;
+	}
 
-	return (isc_hash_function_reverse(name->ndata, length,
-					  case_sensitive, NULL));
+	return (isc_hash_function(name->ndata, length, case_sensitive));
 }
 
 unsigned int
@@ -476,11 +477,11 @@ dns_name_fullhash(const dns_name_t *name, bool case_sensitive) {
 	 */
 	REQUIRE(VALID_NAME(name));
 
-	if (name->labels == 0)
+	if (name->labels == 0) {
 		return (0);
+	}
 
-	return (isc_hash_function_reverse(name->ndata, name->length,
-					  case_sensitive, NULL));
+	return (isc_hash_function(name->ndata, name->length, case_sensitive));
 }
 
 dns_namereln_t
diff --git a/lib/dns/rbtdb.c b/lib/dns/rbtdb.c
index e32acd363b..e7b50e81c2 100644
--- a/lib/dns/rbtdb.c
+++ b/lib/dns/rbtdb.c
@@ -9655,7 +9655,7 @@ rehash_gluetable(rbtdb_version_t *version) {
 		{
 			hash = isc_hash_function(&gluenode->node,
 						 sizeof(gluenode->node),
-						 true, NULL) %
+						 true) %
 				version->glue_table_size;
 			nextgluenode = gluenode->next;
 			gluenode->next = version->glue_table[hash];
@@ -9823,7 +9823,7 @@ rdataset_addglue(dns_rdataset_t *rdataset, dns_dbversion_t *version,
 	 * the node pointer is a fixed value that won't change for a DB
 	 * version and can be compared directly.
 	 */
-	idx = isc_hash_function(&node, sizeof(node), true, NULL) %
+	idx = isc_hash_function(&node, sizeof(node), true) %
 		rbtversion->glue_table_size;
 
 restart:
@@ -9999,8 +9999,7 @@ no_glue:
 	RWLOCK(&rbtversion->glue_rwlock, isc_rwlocktype_write);
 
 	if (ISC_UNLIKELY(rehash_gluetable(rbtversion))) {
-		idx = isc_hash_function(&node, sizeof(node),
-					true, NULL) %
+		idx = isc_hash_function(&node, sizeof(node), true) %
 			rbtversion->glue_table_size;
 	}
 
diff --git a/lib/dns/resolver.c b/lib/dns/resolver.c
index b76b32c0a6..532ecfa590 100644
--- a/lib/dns/resolver.c
+++ b/lib/dns/resolver.c
@@ -23,18 +23,13 @@
 #include <isc/print.h>
 #include <isc/string.h>
 #include <isc/random.h>
+#include <isc/siphash.h>
 #include <isc/socket.h>
 #include <isc/stats.h>
 #include <isc/task.h>
 #include <isc/timer.h>
 #include <isc/util.h>
 
-#ifdef AES_CC
-#include <isc/aes.h>
-#else
-#include <isc/hmac.h>
-#endif
-
 #include <dns/acl.h>
 #include <dns/adb.h>
 #include <dns/badcache.h>
@@ -207,7 +202,7 @@ typedef struct query {
 	isc_mem_t *			mctx;
 	dns_dispatchmgr_t *		dispatchmgr;
 	dns_dispatch_t *		dispatch;
-	bool			exclusivesocket;
+	bool				exclusivesocket;
 	dns_adbaddrinfo_t *		addrinfo;
 	isc_socket_t *			tcpsocket;
 	isc_time_t			start;
@@ -219,7 +214,7 @@ typedef struct query {
 	dns_tsigkey_t			*tsigkey;
 	isc_socketevent_t		sendevent;
 	isc_dscp_t			dscp;
-	int 				ednsversion;
+	int				ednsversion;
 	unsigned int			options;
 	isc_sockeventattr_t		attributes;
 	unsigned int			sends;
@@ -2271,64 +2266,56 @@ add_triededns512(fetchctx_t *fctx, isc_sockaddr_t *address) {
 	ISC_LIST_INITANDAPPEND(fctx->edns512, tried, link);
 }
 
+static inline size_t
+addr2buf(void *buf, const size_t bufsize, const isc_sockaddr_t *sockaddr) {
+	isc_netaddr_t netaddr;
+	isc_netaddr_fromsockaddr(&netaddr, sockaddr);
+	switch (netaddr.family) {
+	case AF_INET:
+		INSIST(bufsize >= 4);
+		memmove(buf, &netaddr.type.in, 4);
+		return (4);
+	case AF_INET6:
+		INSIST(bufsize >= 16);
+		memmove(buf, &netaddr.type.in6, 16);
+		return (16);
+	default:
+		INSIST(0);
+		ISC_UNREACHABLE();
+	}
+	return (0);
+}
+
+static inline isc_socket_t *
+query2sock(const resquery_t *query) {
+	if (query->exclusivesocket) {
+		return (dns_dispatch_getentrysocket(query->dispentry));
+	} else {
+		return (dns_dispatch_getsocket(query->dispatch));
+	}
+}
+
+static inline size_t
+add_serveraddr(uint8_t *buf, const size_t bufsize, const resquery_t *query)
+{
+	return (addr2buf(buf, bufsize, &query->addrinfo->sockaddr));
+}
+
+#define CLIENT_COOKIE_SIZE 8U
+
 static void
-compute_cc(resquery_t *query, unsigned char *cookie, size_t len) {
-#ifdef AES_CC
-	unsigned char digest[ISC_AES_BLOCK_LENGTH];
-	unsigned char input[16];
-	isc_netaddr_t netaddr;
-	unsigned int i;
+compute_cc(const resquery_t *query, uint8_t *cookie, const size_t len) {
+	INSIST(len >= CLIENT_COOKIE_SIZE);
+	STATIC_ASSERT(sizeof(query->fctx->res->view->secret)
+		      >= ISC_SIPHASH24_KEY_LENGTH,
+		      "The view->secret size can't fit SipHash 2-4 key length");
 
-	INSIST(len >= 8U);
+	uint8_t buf[16] ISC_NONSTRING = { 0 };
+	size_t buflen = add_serveraddr(buf, sizeof(buf), query);
 
-	isc_netaddr_fromsockaddr(&netaddr, &query->addrinfo->sockaddr);
-	switch (netaddr.family) {
-	case AF_INET:
-		memmove(input, (unsigned char *)&netaddr.type.in, 4);
-		memset(input + 4, 0, 12);
-		break;
-	case AF_INET6:
-		memmove(input, (unsigned char *)&netaddr.type.in6, 16);
-		break;
-	}
-	isc_aes128_crypt(query->fctx->res->view->secret, input, digest);
-	for (i = 0; i < 8; i++)
-		digest[i] ^= digest[i + 8];
-	memmove(cookie, digest, 8);
-#endif
-#if defined(HMAC_SHA1_CC) || defined(HMAC_SHA256_CC)
-	unsigned char digest[ISC_MAX_MD_SIZE];
-	unsigned char *input = NULL;
-	unsigned int length = 0;
-	isc_netaddr_t netaddr;
-#if defined(HMAC_SHA1_CC)
-	isc_md_type_t type = ISC_MD_SHA1;
-	unsigned int secret_len = ISC_SHA1_DIGESTLENGTH;
-#elif defined(HMAC_SHA256_CC)
-	isc_md_type_t type = ISC_MD_SHA256;
-	unsigned int secret_len = ISC_SHA256_DIGESTLENGTH;
-#endif
-
-	INSIST(len >= 8U);
-
-	isc_netaddr_fromsockaddr(&netaddr, &query->addrinfo->sockaddr);
-	switch (netaddr.family) {
-	case AF_INET:
-		input = (unsigned char *)&netaddr.type.in;
-		length = 4;
-		break;
-	case AF_INET6:
-		input = (unsigned char *)&netaddr.type.in6;
-		length = 16;
-		break;
-	}
-
-	RUNTIME_CHECK(isc_hmac(type,
-			       query->fctx->res->view->secret, secret_len,
-			       input, length,
-			       digest, NULL) == ISC_R_SUCCESS);
-	memmove(cookie, digest, 8);
-#endif
+	uint8_t digest[ISC_SIPHASH24_TAG_LENGTH] ISC_NONSTRING = { 0 };
+	isc_siphash24(query->fctx->res->view->secret, buf, buflen, digest);
+	memmove(cookie, digest, CLIENT_COOKIE_SIZE);
 }
 
 static isc_result_t
@@ -2788,10 +2775,8 @@ resquery_send(resquery_t *query) {
 	 */
 	dns_message_reset(fctx->qmessage, DNS_MESSAGE_INTENTRENDER);
 
-	if (query->exclusivesocket)
-		sock = dns_dispatch_getentrysocket(query->dispentry);
-	else
-		sock = dns_dispatch_getsocket(query->dispatch);
+	sock = query2sock(query);
+
 	/*
 	 * Send the query!
 	 */
@@ -5360,9 +5345,9 @@ validated(isc_task_t *task, isc_event_t *event) {
 	REQUIRE(event->ev_type == DNS_EVENT_VALIDATORDONE);
 	valarg = event->ev_arg;
 	fctx = valarg->fctx;
+	REQUIRE(VALID_FCTX(fctx));
 	res = fctx->res;
 	addrinfo = valarg->addrinfo;
-	REQUIRE(VALID_FCTX(fctx));
 	REQUIRE(!ISC_LIST_EMPTY(fctx->validators));
 
 	vevent = (dns_validatorevent_t *)event;
@@ -9587,11 +9572,7 @@ rctx_logpacket(respctx_t *rctx) {
 		dtmsgtype = DNS_DTTYPE_RR;
 	}
 
-	if (rctx->query->exclusivesocket) {
-		sock = dns_dispatch_getentrysocket(rctx->query->dispentry);
-	} else {
-		sock = dns_dispatch_getsocket(rctx->query->dispatch);
-	}
+	sock = query2sock(rctx->query);
 
 	if (sock != NULL) {
 		result = isc_socket_getsockname(sock, &localaddr);
diff --git a/lib/isc/Makefile.in b/lib/isc/Makefile.in
index ed87279e7f..971503c448 100644
--- a/lib/isc/Makefile.in
+++ b/lib/isc/Makefile.in
@@ -53,7 +53,7 @@ OBJS =		pk11.@O@ pk11_result.@O@ \
 		parseint.@O@ portset.@O@ quota.@O@ radix.@O@ random.@O@ \
 		ratelimiter.@O@ region.@O@ regex.@O@ result.@O@ \
 		rwlock.@O@ \
-		serial.@O@ sockaddr.@O@ stats.@O@ \
+		serial.@O@ siphash.@O@ sockaddr.@O@ stats.@O@ \
 		string.@O@ symtab.@O@ task.@O@ taskpool.@O@ \
 		tm.@O@ timer.@O@ version.@O@ \
 		${UNIXOBJS} ${THREADOBJS}
@@ -70,7 +70,7 @@ SRCS =		pk11.c pk11_result.c \
 		netaddr.c netscope.c nonce.c openssl_shim.c pool.c \
 		parseint.c portset.c quota.c radix.c random.c \
 		ratelimiter.c region.c regex.c result.c rwlock.c \
-		serial.c sockaddr.c stats.c string.c \
+		serial.c siphash.c sockaddr.c stats.c string.c \
 		symtab.c task.c taskpool.c timer.c \
 		tm.c version.c
 
diff --git a/lib/isc/hash.c b/lib/isc/hash.c
index 456e94588a..4aa90beb23 100644
--- a/lib/isc/hash.c
+++ b/lib/isc/hash.c
@@ -18,6 +18,9 @@
 #include <stdbool.h>
 #include <stddef.h>
 #include <inttypes.h>
+#if defined(WIN32) || defined(WIN64)
+#include <malloc.h>
+#endif
 
 #include "isc/hash.h" // IWYU pragma: keep
 #include "isc/likely.h"
@@ -26,12 +29,31 @@
 #include "isc/result.h"
 #include "isc/types.h"
 #include "isc/util.h"
+#include "isc/siphash.h"
+#include "isc/string.h"
 
-static uint32_t fnv_offset_basis;
-static isc_once_t fnv_once = ISC_ONCE_INIT;
-static bool fnv_initialized = false;
+#include "entropy_private.h"
 
-static unsigned char maptolower[] = {
+static uint8_t isc_hash_key[16];
+static bool hash_initialized = false;
+static isc_once_t isc_hash_once = ISC_ONCE_INIT;
+
+static void
+isc_hash_initialize(void) {
+	uint64_t key[2] = { 0, 1 };
+#if FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
+	/*
+	 * Set a constant key to help in problem reproduction should
+	 * fuzzing find a crash or a hang.
+	 */
+#else
+	isc_entropy_get(key, sizeof(key));
+#endif
+	memmove(isc_hash_key, key, sizeof(isc_hash_key));
+	hash_initialized = true;
+}
+
+static uint8_t maptolower[] = {
 	0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
 	0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
 	0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17,
@@ -66,27 +88,15 @@ static unsigned char maptolower[] = {
 	0xf8, 0xf9, 0xfa, 0xfb, 0xfc, 0xfd, 0xfe, 0xff
 };
 
-static void
-fnv_initialize(void) {
-	/*
-	 * This function should not leave fnv_offset_basis set to
-	 * 0. Also, after this function has been called, if it is called
-	 * again, it should not change fnv_offset_basis.
-	 */
-	while (fnv_offset_basis == 0) {
-		fnv_offset_basis = isc_random32();
-	}
-
-	fnv_initialized = true;
-}
-
 const void *
 isc_hash_get_initializer(void) {
-	if (ISC_UNLIKELY(!fnv_initialized))
-		RUNTIME_CHECK(isc_once_do(&fnv_once, fnv_initialize) ==
-			      ISC_R_SUCCESS);
+	if (ISC_UNLIKELY(!hash_initialized)) {
+		RUNTIME_CHECK(isc_once_do(&isc_hash_once,
+					  isc_hash_initialize)
+			      == ISC_R_SUCCESS);
+	}
 
-	return (&fnv_offset_basis);
+	return (isc_hash_key);
 }
 
 void
@@ -94,111 +104,39 @@ isc_hash_set_initializer(const void *initializer) {
 	REQUIRE(initializer != NULL);
 
 	/*
-	 * Ensure that fnv_initialize() is not called after
+	 * Ensure that isc_hash_initialize() is not called after
 	 * isc_hash_set_initializer() is called.
 	 */
-	if (ISC_UNLIKELY(!fnv_initialized))
-		RUNTIME_CHECK(isc_once_do(&fnv_once, fnv_initialize) ==
-			      ISC_R_SUCCESS);
+	if (ISC_UNLIKELY(!hash_initialized)) {
+		RUNTIME_CHECK(isc_once_do(&isc_hash_once,
+					  isc_hash_initialize)
+			      == ISC_R_SUCCESS);
+	}
 
-	fnv_offset_basis = *((const unsigned int *)initializer);
+	memmove(isc_hash_key, initializer, sizeof(isc_hash_key));
 }
 
-#define FNV_32_PRIME ((uint32_t)0x01000193)
-
-uint32_t
-isc_hash_function(const void *data, size_t length, bool case_sensitive,
-		  const uint32_t *previous_hashp)
+uint64_t
+isc_hash_function(const void *data,
+		  const size_t length,
+		  const bool case_sensitive)
 {
-	uint32_t hval;
-	const unsigned char *bp;
-	const unsigned char *be;
+	uint64_t hval;
 
 	REQUIRE(length == 0 || data != NULL);
 
-	if (ISC_UNLIKELY(!fnv_initialized)) {
-		RUNTIME_CHECK(isc_once_do(&fnv_once, fnv_initialize) ==
-			      ISC_R_SUCCESS);
-	}
-
-	hval = ISC_UNLIKELY(previous_hashp != NULL) ? *previous_hashp
-						    : fnv_offset_basis;
-
-	if (length == 0) {
-		return (hval);
-	}
-
-	bp = (const unsigned char *)data;
-	be = bp + length;
-
-	/*
-	 * Fowler-Noll-Vo FNV-1a hash function.
-	 *
-	 * NOTE: A random FNV offset basis is used by default to avoid
-	 * collision attacks as the hash function is reversible. This
-	 * makes the mapping non-deterministic, but the distribution in
-	 * the domain is still uniform.
-	 */
+	RUNTIME_CHECK(isc_once_do(&isc_hash_once,
+				  isc_hash_initialize) == ISC_R_SUCCESS);
 
 	if (case_sensitive) {
-		while (bp < be) {
-			hval ^= *bp++;
-			hval *= FNV_32_PRIME;
-		}
+		isc_siphash24(isc_hash_key, data, length, (uint8_t *)&hval);
 	} else {
-		while (bp < be) {
-			hval ^= maptolower[*bp++];
-			hval *= FNV_32_PRIME;
-		}
-	}
-
-	return (hval);
-}
-
-uint32_t
-isc_hash_function_reverse(const void *data, size_t length, bool case_sensitive,
-			  const uint32_t *previous_hashp)
-{
-	uint32_t hval;
-	const unsigned char *bp;
-	const unsigned char *be;
-
-	REQUIRE(length == 0 || data != NULL);
-
-	if (ISC_UNLIKELY(!fnv_initialized)) {
-		RUNTIME_CHECK(isc_once_do(&fnv_once, fnv_initialize) ==
-			      ISC_R_SUCCESS);
-	}
-
-	hval = ISC_UNLIKELY(previous_hashp != NULL) ? *previous_hashp
-						    : fnv_offset_basis;
-
-	if (length == 0) {
-		return (hval);
-	}
-
-	bp = (const unsigned char *)data;
-	be = bp + length;
-
-	/*
-	 * Fowler-Noll-Vo FNV-1a hash function.
-	 *
-	 * NOTE: A random FNV offset basis is used by default to avoid
-	 * collision attacks as the hash function is reversible. This
-	 * makes the mapping non-deterministic, but the distribution in
-	 * the domain is still uniform.
-	 */
-
-	if (case_sensitive) {
-		while (--be >= bp) {
-			hval ^= *be;
-			hval *= FNV_32_PRIME;
-		}
-	} else {
-		while (--be >= bp) {
-			hval ^= maptolower[*be];
-			hval *= FNV_32_PRIME;
+		uint8_t input[1024];
+		REQUIRE(length <= 1024);
+		for (unsigned int i = 0; i < length; i++) {
+			input[i] = maptolower[((const uint8_t *)data)[i]];
 		}
+		isc_siphash24(isc_hash_key, input, length, (uint8_t *)&hval);
 	}
 
 	return (hval);
diff --git a/lib/isc/ht.c b/lib/isc/ht.c
index fde728a4f6..40da5e4f41 100644
--- a/lib/isc/ht.c
+++ b/lib/isc/ht.c
@@ -130,7 +130,7 @@ isc_ht_add(isc_ht_t *ht, const unsigned char *key,
 	REQUIRE(ISC_HT_VALID(ht));
 	REQUIRE(key != NULL && keysize > 0);
 
-	hash = isc_hash_function(key, keysize, true, NULL);
+	hash = isc_hash_function(key, keysize, true);
 	node = ht->table[hash & ht->mask];
 	while (node != NULL) {
 		if (keysize == node->keysize &&
@@ -165,7 +165,7 @@ isc_ht_find(const isc_ht_t *ht, const unsigned char *key,
 	REQUIRE(key != NULL && keysize > 0);
 	REQUIRE(valuep == NULL || *valuep == NULL);
 
-	hash = isc_hash_function(key, keysize, true, NULL);
+	hash = isc_hash_function(key, keysize, true);
 	node = ht->table[hash & ht->mask];
 	while (node != NULL) {
 		if (keysize == node->keysize &&
@@ -190,7 +190,7 @@ isc_ht_delete(isc_ht_t *ht, const unsigned char *key, uint32_t keysize) {
 	REQUIRE(key != NULL && keysize > 0);
 
 	prev = NULL;
-	hash = isc_hash_function(key, keysize, true, NULL);
+	hash = isc_hash_function(key, keysize, true);
 	node = ht->table[hash & ht->mask];
 	while (node != NULL) {
 		if (keysize == node->keysize &&
@@ -305,8 +305,7 @@ isc_ht_iter_delcurrent_next(isc_ht_iter_t *it) {
 			it->cur = ht->table[it->i];
 	}
 
-	hash = isc_hash_function(to_delete->key, to_delete->keysize, true,
-				 NULL);
+	hash = isc_hash_function(to_delete->key, to_delete->keysize, true);
 	node = ht->table[hash & ht->mask];
 	while (node != to_delete) {
 		prev = node;
diff --git a/lib/isc/include/isc/Makefile.in b/lib/isc/include/isc/Makefile.in
index 9577e4bd9e..2e1cb4ab22 100644
--- a/lib/isc/include/isc/Makefile.in
+++ b/lib/isc/include/isc/Makefile.in
@@ -21,7 +21,7 @@ VERSION=@BIND9_VERSION@
 HEADERS =	aes.h app.h assertions.h atomic.h backtrace.h \
 		base32.h base64.h bind9.h buffer.h bufferlist.h \
 		commandline.h counter.h crc64.h deprecated.h \
-		errno.h error.h event.h eventclass.h \
+		endian.h errno.h error.h event.h eventclass.h \
 		file.h formatcheck.h fsaccess.h fuzz.h \
 		hash.h heap.h hex.h hmac.h ht.h httpd.h \
 		interfaceiter.h iterated_hash.h \
@@ -31,7 +31,7 @@ HEADERS =	aes.h app.h assertions.h atomic.h backtrace.h \
 		pool.h portset.h print.h queue.h quota.h \
 		radix.h random.h ratelimiter.h refcount.h regex.h \
 		region.h resource.h result.h resultclass.h rwlock.h \
-		safe.h serial.h sockaddr.h socket.h \
+		safe.h serial.h siphash.h sockaddr.h socket.h \
 		stats.h stdio.h strerr.h string.h symtab.h \
 	        task.h taskpool.h timer.h tm.h types.h util.h version.h \
 		xml.h
diff --git a/lib/isc/include/isc/endian.h b/lib/isc/include/isc/endian.h
new file mode 100644
index 0000000000..54421d55d4
--- /dev/null
+++ b/lib/isc/include/isc/endian.h
@@ -0,0 +1,187 @@
+/*
+ * Copyright (C) Internet Systems Consortium, Inc. ("ISC")
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * See the COPYRIGHT file distributed with this work for additional
+ * information regarding copyright ownership.
+ */
+
+#pragma once
+
+#if defined(__DragonFly__) || defined(__FreeBSD__) || \
+    defined(__NetBSD__) || defined (__OpenBSD__) || defined(__bsdi__)
+
+# include <sys/endian.h>
+
+/*
+ * Recent BSDs should have [bl]e{16,32,64}toh() defined in <sys/endian.h>.
+ * Older ones might not, but these should have the alternatively named
+ * [bl]etoh{16,32,64}() functions defined.
+ */
+# ifndef be16toh
+#  define be16toh(x) betoh16(x)
+#  define le16toh(x) letoh16(x)
+#  define be32toh(x) betoh32(x)
+#  define le32toh(x) letoh32(x)
+#  define be64toh(x) betoh64(x)
+#  define le64toh(x) letoh64(x)
+# endif /* !be16toh */
+
+#elif defined(_WIN32)
+
+/*
+ * Windows is always little-endian and has its own byte-swapping routines, so
+ * use these.
+ */
+
+# include <stdlib.h>
+
+# define htobe16(x) _byteswap_ushort(x)
+# define htole16(x) (x)
+# define be16toh(x) _byteswap_ushort(x)
+# define le16toh(x) (x)
+
+# define htobe32(x) _byteswap_ulong(x)
+# define htole32(x) (x)
+# define be32toh(x) _byteswap_ulong(x)
+# define le32toh(x) (x)
+
+# define htobe64(x) _byteswap_uint64(x)
+# define htole64(x) (x)
+# define be64toh(x) _byteswap_uint64(x)
+# define le64toh(x) (x)
+
+#elif defined __APPLE__
+
+/*
+ * macOS has its own byte-swapping routines, so use these.
+ */
+
+# include <libkern/OSByteOrder.h>
+
+# define htobe16(x) OSSwapHostToBigInt16(x)
+# define htole16(x) OSSwapHostToLittleInt16(x)
+# define be16toh(x) OSSwapBigToHostInt16(x)
+# define le16toh(x) OSSwapLittleToHostInt16(x)
+
+# define htobe32(x) OSSwapHostToBigInt32(x)
+# define htole32(x) OSSwapHostToLittleInt32(x)
+# define be32toh(x) OSSwapBigToHostInt32(x)
+# define le32toh(x) OSSwapLittleToHostInt32(x)
+
+# define htobe64(x) OSSwapHostToBigInt64(x)
+# define htole64(x) OSSwapHostToLittleInt64(x)
+# define be64toh(x) OSSwapBigToHostInt64(x)
+# define le64toh(x) OSSwapLittleToHostInt64(x)
+
+#elif defined(sun) || defined(__sun) || defined(__SVR4)
+
+/*
+ * For Solaris, rely on the fallback definitions below, though use
+ * Solaris-specific versions of bswap_{16,32,64}().
+ */
+
+# include <sys/byteorder.h>
+
+# define bswap_16(x) BSWAP_16(x)
+# define bswap_32(x) BSWAP_32(x)
+# define bswap_64(x) BSWAP_64(x)
+
+#elif defined(__ANDROID__) || defined(__CYGWIN__) || \
+      defined(__GNUC__) || defined(__GNU__)
+
+# include <byteswap.h>
+# include <endian.h>
+
+#else
+
+#endif /* Specific platform support */
+
+/*
+ * Fallback definitions.
+ */
+
+#include <inttypes.h>
+
+#ifndef bswap_16
+# define bswap_16(x) \
+	((uint16_t)((((uint16_t) (x) & 0xff00) >> 8) |			\
+		    (((uint16_t) (x) & 0x00ff) << 8)))
+#endif /* !bswap_16 */
+
+#ifndef bswap_32
+# define bswap_32(x) \
+	((uint32_t)((((uint32_t) (x) & 0xff000000) >> 24) |		\
+		    (((uint32_t) (x) & 0x00ff0000) >> 8)  |		\
+		    (((uint32_t) (x) & 0x0000ff00) << 8)  |		\
+		    (((uint32_t) (x) & 0x000000ff) << 24)))
+#endif /* !bswap_32 */
+
+#ifndef bswap_64
+# define bswap_64(x) \
+	((uint64_t)((((uint64_t) (x) & 0xff00000000000000ULL) >> 56) |	\
+		    (((uint64_t) (x) & 0x00ff000000000000ULL) >> 40) |	\
+		    (((uint64_t) (x) & 0x0000ff0000000000ULL) >> 24) |	\
+		    (((uint64_t) (x) & 0x000000ff00000000ULL) >> 8)  |	\
+		    (((uint64_t) (x) & 0x00000000ff000000ULL) << 8)  |	\
+		    (((uint64_t) (x) & 0x0000000000ff0000ULL) << 24) |	\
+		    (((uint64_t) (x) & 0x000000000000ff00ULL) << 40) |	\
+		    (((uint64_t) (x) & 0x00000000000000ffULL) << 56)))
+#endif /* !bswap_64 */
+
+#ifndef htobe16
+# if WORDS_BIGENDIAN
+
+#  define htobe16(x) (x)
+#  define htole16(x) bswap_16(x)
+#  define be16toh(x) (x)
+#  define le16toh(x) bswap_16(x)
+
+# else /* WORDS_BIGENDIAN */
+
+#  define htobe16(x) bswap_16(x)
+#  define htole16(x) (x)
+#  define be16toh(x) bswap_16(x)
+#  define le16toh(x) (x)
+
+# endif /* WORDS_BIGENDIAN */
+#endif /* !htobe16 */
+
+#ifndef htobe32
+# if WORDS_BIGENDIAN
+
+#  define htobe32(x) (x)
+#  define htole32(x) bswap_32(x)
+#  define be32toh(x) (x)
+#  define le32toh(x) bswap_32(x)
+
+# else /* WORDS_BIGENDIAN */
+
+#  define htobe32(x) bswap_32(x)
+#  define htole32(x) (x)
+#  define be32toh(x) bswap_32(x)
+#  define le32toh(x) (x)
+
+# endif /* WORDS_BIGENDIAN */
+#endif /* !htobe32 */
+
+#ifndef htobe64
+# if WORDS_BIGENDIAN
+
+#  define htobe64(x) (x)
+#  define htole64(x) bswap_64(x)
+#  define be64toh(x) (x)
+#  define le64toh(x) bswap_64(x)
+
+#else /* WORDS_BIGENDIAN */
+
+#  define htobe64(x) bswap_64(x)
+#  define htole64(x) (x)
+#  define be64toh(x) bswap_64(x)
+#  define le64toh(x) (x)
+
+# endif /* WORDS_BIGENDIAN */
+#endif /* !htobe64 */
diff --git a/lib/isc/include/isc/hash.h b/lib/isc/include/isc/hash.h
index 5b4336e68e..3989d0449e 100644
--- a/lib/isc/include/isc/hash.h
+++ b/lib/isc/include/isc/hash.h
@@ -29,14 +29,9 @@ isc_hash_get_initializer(void);
 void
 isc_hash_set_initializer(const void *initializer);
 
-uint32_t
-isc_hash_function(const void *data, size_t length,
-		  bool case_sensitive,
-		  const uint32_t *previous_hashp);
-uint32_t
-isc_hash_function_reverse(const void *data, size_t length,
-			  bool case_sensitive,
-			  const uint32_t *previous_hashp);
+uint64_t
+isc_hash_function(const void *data, const size_t length,
+		  const bool case_sensitive);
 /*!<
  * \brief Calculate a hash over data.
  *
@@ -47,10 +42,7 @@ isc_hash_function_reverse(const void *data, size_t length,
  * distribution.
  *
  * isc_hash_function() calculates the hash from start to end over the
- * input data. isc_hash_function_reverse() calculates the hash from the
- * end to the start over the input data. The difference in order is
- * useful in incremental hashing; for example, a previously hashed
- * value for 'com' can be used as input when hashing 'example.com'.
+ * input data.
  *
  * 'data' is the data to be hashed.
  *
@@ -60,9 +52,9 @@ isc_hash_function_reverse(const void *data, size_t length,
  * case_sensitive values.  It should typically be false if the hash key
  * is a DNS name.
  *
- * 'previous_hashp' is a pointer to a previous hash value returned by
- * this function. It can be used to perform incremental hashing. NULL
- * must be passed during first calls.
+ * WARNING: In case of case insensitive input, the input buffer cannot
+ * be longer than 1024, which should be fine, as it is only used for
+ * DNS names.
  */
 
 ISC_LANG_ENDDECLS
diff --git a/lib/isc/include/isc/siphash.h b/lib/isc/include/isc/siphash.h
new file mode 100644
index 0000000000..472e8f2253
--- /dev/null
+++ b/lib/isc/include/isc/siphash.h
@@ -0,0 +1,31 @@
+/*
+ * Copyright (C) Internet Systems Consortium, Inc. ("ISC")
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * See the COPYRIGHT file distributed with this work for additional
+ * information regarding copyright ownership.
+ */
+
+
+/*! \file isc/siphash.h */
+
+#pragma once
+
+#include <isc/lang.h>
+#include <isc/platform.h>
+#include <isc/types.h>
+
+#define ISC_SIPHASH24_KEY_LENGTH 128 / 8
+#define ISC_SIPHASH24_TAG_LENGTH 64 / 8
+
+ISC_LANG_BEGINDECLS
+
+void
+isc_siphash24(const uint8_t *key,
+	      const uint8_t *in, size_t inlen,
+	      uint8_t *out);
+
+ISC_LANG_ENDDECLS
diff --git a/lib/isc/include/isc/util.h b/lib/isc/include/isc/util.h
index 4dfe1d77e4..6602aac2b3 100644
--- a/lib/isc/include/isc/util.h
+++ b/lib/isc/include/isc/util.h
@@ -42,6 +42,12 @@
  */
 #define UNUSED(x)      (void)(x)
 
+#if __GNUC__ >= 8 && !defined(__clang__)
+#define ISC_NONSTRING	__attribute__((nonstring))
+#else
+#define ISC_NONSTRING
+#endif /* __GNUC__ */
+
 /*%
  * The opposite: silent warnings about stored values which are never read.
  */
diff --git a/lib/isc/mem.c b/lib/isc/mem.c
index 01a42a4e25..820faa5b55 100644
--- a/lib/isc/mem.c
+++ b/lib/isc/mem.c
@@ -263,7 +263,7 @@ add_trace_entry(isc__mem_t *mctx, const void *ptr, size_t size FLARG) {
 	if (mctx->debuglist == NULL)
 		return;
 
-	hash = isc_hash_function(&ptr, sizeof(ptr), true, NULL);
+	hash = isc_hash_function(&ptr, sizeof(ptr), true);
 	idx = hash % DEBUG_TABLE_COUNT;
 
 	dl = malloc(sizeof(debuglink_t));
@@ -298,7 +298,7 @@ delete_trace_entry(isc__mem_t *mctx, const void *ptr, size_t size,
 	if (mctx->debuglist == NULL)
 		return;
 
-	hash = isc_hash_function(&ptr, sizeof(ptr), true, NULL);
+	hash = isc_hash_function(&ptr, sizeof(ptr), true);
 	idx = hash % DEBUG_TABLE_COUNT;
 
 	dl = ISC_LIST_HEAD(mctx->debuglist[idx]);
diff --git a/lib/isc/siphash.c b/lib/isc/siphash.c
new file mode 100644
index 0000000000..c9f73934ee
--- /dev/null
+++ b/lib/isc/siphash.c
@@ -0,0 +1,137 @@
+/*
+ * Copyright (C) Internet Systems Consortium, Inc. ("ISC")
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * See the COPYRIGHT file distributed with this work for additional
+ * information regarding copyright ownership.
+ */
+
+/*
+   siphash() function is SipHash reference C implementation
+
+   Copyright (c) 2012-2016 Jean-Philippe Aumasson <jeanphilippe.aumasson@gmail.com>
+   Copyright (c) 2012-2014 Daniel J. Bernstein <djb@cr.yp.to>
+
+   To the extent possible under law, the author(s) have dedicated all copyright
+   and related and neighboring rights to this software to the public domain
+   worldwide. This software is distributed without any warranty.
+
+   You should have received a copy of the CC0 Public Domain Dedication along
+   with this software. If not, see <http://creativecommons.org/publicdomain/zero/1.0/>.
+ */
+
+/*! \file isc/siphash.c */
+
+#include <config.h>
+
+#include <inttypes.h>
+#include <unistd.h>
+#include <string.h>
+
+#include <openssl/opensslv.h>
+
+#include <isc/endian.h>
+#include <isc/util.h>
+#include <isc/siphash.h>
+
+#define ROTATE(x, b) (uint64_t)( ((x) << (b)) | ( (x) >> (64 - (b))) )
+
+#define HALF_ROUND(a, b, c, d, s, t)		 \
+	a += b; c += d;				 \
+	b = ROTATE(b, s) ^ a;			 \
+	d = ROTATE(d, t) ^ c;			 \
+	a = ROTATE(a, 32);
+
+#define FULL_ROUND(v0, v1, v2, v3)			      \
+	HALF_ROUND(v0, v1, v2, v3, 13, 16);		      \
+	HALF_ROUND(v2, v1, v0, v3, 17, 21);
+
+#define DOUBLE_ROUND(v0, v1, v2, v3)		\
+	FULL_ROUND(v0, v1, v2, v3)			\
+	FULL_ROUND(v0, v1, v2, v3)
+
+#define SIPROUND FULL_ROUND
+
+void
+isc_siphash24(const uint8_t *k, const uint8_t *in, size_t inlen, uint8_t *out)
+{
+	const uint64_t *key = (const uint64_t *)k;
+	uint64_t k0 = le64toh(key[0]);
+	uint64_t k1 = le64toh(key[1]);
+
+	uint64_t v0 = 0x736f6d6570736575ULL ^ k0;
+	uint64_t v1 = 0x646f72616e646f6dULL ^ k1;
+	uint64_t v2 = 0x6c7967656e657261ULL ^ k0;
+	uint64_t v3 = 0x7465646279746573ULL ^ k1;
+
+	size_t left = inlen;
+
+	uint64_t b = ((uint64_t)inlen) << 56;
+
+	const uint64_t *inbuf = (const uint64_t *)in;
+	while (left >= 8) {
+		uint64_t m = le64toh(*inbuf);
+
+		v3 ^= m;
+
+		SIPROUND(v0, v1, v2, v3);
+		SIPROUND(v0, v1, v2, v3);
+
+		v0 ^= m;
+
+		inbuf++; left -= 8;
+	}
+
+	const uint8_t *end = in + (inlen - left);
+
+	switch (left) {
+	case 7:
+		b |= ((uint64_t)end[6]) << 48;
+		/* FALLTHROUGH */
+	case 6:
+		b |= ((uint64_t)end[5]) << 40;
+		/* FALLTHROUGH */
+	case 5:
+		b |= ((uint64_t)end[4]) << 32;
+		/* FALLTHROUGH */
+	case 4:
+		b |= ((uint64_t)end[3]) << 24;
+		/* FALLTHROUGH */
+	case 3:
+		b |= ((uint64_t)end[2]) << 16;
+		/* FALLTHROUGH */
+	case 2:
+		b |= ((uint64_t)end[1]) << 8;
+		/* FALLTHROUGH */
+	case 1:
+		b |= ((uint64_t)end[0]);
+		/* FALLTHROUGH */
+	case 0:
+		break;
+	default:
+		INSIST(0);
+		ISC_UNREACHABLE();
+	}
+
+	v3 ^= b;
+
+	SIPROUND(v0, v1, v2, v3);
+	SIPROUND(v0, v1, v2, v3);
+
+	v0 ^= b;
+
+	v2 ^= 0xff;
+
+	SIPROUND(v0, v1, v2, v3);
+	SIPROUND(v0, v1, v2, v3);
+	SIPROUND(v0, v1, v2, v3);
+	SIPROUND(v0, v1, v2, v3);
+
+	b = v0 ^ v1 ^ v2 ^ v3;
+
+	uint64_t *outbuf = (uint64_t *)out;
+	*outbuf = htole64(b);
+}
diff --git a/lib/isc/sockaddr.c b/lib/isc/sockaddr.c
index a417c252e0..bb28291aab 100644
--- a/lib/isc/sockaddr.c
+++ b/lib/isc/sockaddr.c
@@ -16,6 +16,9 @@
 
 #include <stdbool.h>
 #include <stdio.h>
+#if defined(WIN32) || defined(WIN64)
+#include <malloc.h>
+#endif
 
 #include <isc/buffer.h>
 #include <isc/hash.h>
@@ -224,9 +227,14 @@ isc_sockaddr_hash(const isc_sockaddr_t *sockaddr, bool address_only) {
 		p = 0;
 	}
 
-	h = isc_hash_function(s, length, true, NULL);
-	if (!address_only)
-		h = isc_hash_function(&p, sizeof(p), true, &h);
+	uint8_t buf[sizeof(struct sockaddr_storage) + sizeof(p)];
+	memmove(buf, s, length);
+	if (!address_only) {
+		memmove(buf + length, &p, sizeof(p));
+		h = isc_hash_function(buf, length + sizeof(p), true);
+	} else {
+		h = isc_hash_function(buf, length, true);
+	}
 
 	return (h);
 }
diff --git a/lib/isc/tests/Makefile.in b/lib/isc/tests/Makefile.in
index 5735829728..7a68a78c5c 100644
--- a/lib/isc/tests/Makefile.in
+++ b/lib/isc/tests/Makefile.in
@@ -30,7 +30,7 @@ SRCS =		isctest.c aes_test.c buffer_test.c \
 		heap_test.c hmac_test.c ht_test.c lex_test.c \
 		mem_test.c md_test.c netaddr_test.c parse_test.c pool_test.c \
 		queue_test.c radix_test.c random_test.c \
-		regex_test.c result_test.c safe_test.c sockaddr_test.c \
+		regex_test.c result_test.c safe_test.c siphash_test.c sockaddr_test.c \
 		socket_test.c socket_test.c symtab_test.c task_test.c \
 		taskpool_test.c time_test.c timer_test.c
 
@@ -44,7 +44,7 @@ TARGETS =	aes_test@EXEEXT@ buffer_test@EXEEXT@ \
 		netaddr_test@EXEEXT@ parse_test@EXEEXT@ pool_test@EXEEXT@ \
 		queue_test@EXEEXT@ radix_test@EXEEXT@ \
 		random_test@EXEEXT@ regex_test@EXEEXT@ result_test@EXEEXT@ \
-		safe_test@EXEEXT@ sockaddr_test@EXEEXT@ socket_test@EXEEXT@ \
+		safe_test@EXEEXT@ siphash_test@EXEEXT@ sockaddr_test@EXEEXT@ socket_test@EXEEXT@ \
 		socket_test@EXEEXT@ symtab_test@EXEEXT@ task_test@EXEEXT@ \
 		taskpool_test@EXEEXT@ time_test@EXEEXT@ timer_test@EXEEXT@
 
@@ -160,6 +160,11 @@ safe_test@EXEEXT@: safe_test.@O@ ${ISCDEPLIBS}
 		${LDFLAGS} -o $@ safe_test.@O@ \
 		${ISCLIBS} ${LIBS}
 
+siphash_test@EXEEXT@: siphash_test.@O@ ../siphash.c ${ISCDEPLIBS}
+	${LIBTOOL_MODE_LINK} ${PURIFY} ${CC} ${CFLAGS} \
+		${LDFLAGS} -o $@ siphash_test.@O@ \
+		${ISCLIBS} ${LIBS}
+
 socket_test@EXEEXT@: socket_test.@O@ isctest.@O@ ${ISCDEPLIBS}
 	${LIBTOOL_MODE_LINK} ${PURIFY} ${CC} ${CFLAGS} \
 		${LDFLAGS} -o $@ socket_test.@O@ isctest.@O@ \
diff --git a/lib/isc/tests/hash_test.c b/lib/isc/tests/hash_test.c
index 22bb6e478f..0ffe4392d6 100644
--- a/lib/isc/tests/hash_test.c
+++ b/lib/isc/tests/hash_test.c
@@ -39,13 +39,6 @@
 
 #define TEST_INPUT(x) (x), sizeof(x)-1
 
-typedef struct hash_testcase {
-	const char *input;
-	size_t input_len;
-	const char *result;
-	int repeats;
-} hash_testcase_t;
-
 /*Hash function test */
 static void
 isc_hash_function_test(void **state) {
@@ -54,88 +47,31 @@ isc_hash_function_test(void **state) {
 
 	UNUSED(state);
 
-	/* Incremental hashing */
-
-	h1 = isc_hash_function(NULL, 0, true, NULL);
-	h1 = isc_hash_function("This ", 5, true, &h1);
-	h1 = isc_hash_function("is ", 3, true, &h1);
-	h1 = isc_hash_function("a long test", 12, true, &h1);
-
-	h2 = isc_hash_function("This is a long test", 20,
-			       true, NULL);
-
-	assert_int_equal(h1, h2);
-
 	/* Immutability of hash function */
-	h1 = isc_hash_function(NULL, 0, true, NULL);
-	h2 = isc_hash_function(NULL, 0, true, NULL);
+	h1 = isc_hash_function(NULL, 0, true);
+	h2 = isc_hash_function(NULL, 0, true);
 
 	assert_int_equal(h1, h2);
 
 	/* Hash function characteristics */
-	h1 = isc_hash_function("Hello world", 12, true, NULL);
-	h2 = isc_hash_function("Hello world", 12, true, NULL);
+	h1 = isc_hash_function("Hello world", 12, true);
+	h2 = isc_hash_function("Hello world", 12, true);
 
 	assert_int_equal(h1, h2);
 
 	/* Case */
-	h1 = isc_hash_function("Hello world", 12, false, NULL);
-	h2 = isc_hash_function("heLLo WorLd", 12, false, NULL);
+	h1 = isc_hash_function("Hello world", 12, false);
+	h2 = isc_hash_function("heLLo WorLd", 12, false);
 
 	assert_int_equal(h1, h2);
 
 	/* Unequal */
-	h1 = isc_hash_function("Hello world", 12, true, NULL);
-	h2 = isc_hash_function("heLLo WorLd", 12, true, NULL);
+	h1 = isc_hash_function("Hello world", 12, true);
+	h2 = isc_hash_function("heLLo WorLd", 12, true);
 
 	assert_int_not_equal(h1, h2);
 }
 
-/* Reverse hash function test */
-static void
-isc_hash_function_reverse_test(void **state) {
-	unsigned int h1;
-	unsigned int h2;
-
-	UNUSED(state);
-
-	/* Incremental hashing */
-
-	h1 = isc_hash_function_reverse(NULL, 0, true, NULL);
-	h1 = isc_hash_function_reverse("\000", 1, true, &h1);
-	h1 = isc_hash_function_reverse("\003org", 4, true, &h1);
-	h1 = isc_hash_function_reverse("\007example", 8, true, &h1);
-
-	h2 = isc_hash_function_reverse("\007example\003org\000", 13,
-				       true, NULL);
-
-	assert_int_equal(h1, h2);
-
-	/* Immutability of hash function */
-	h1 = isc_hash_function_reverse(NULL, 0, true, NULL);
-	h2 = isc_hash_function_reverse(NULL, 0, true, NULL);
-
-	assert_int_equal(h1, h2);
-
-	/* Hash function characteristics */
-	h1 = isc_hash_function_reverse("Hello world", 12, true, NULL);
-	h2 = isc_hash_function_reverse("Hello world", 12, true, NULL);
-
-	assert_int_equal(h1, h2);
-
-	/* Case */
-	h1 = isc_hash_function_reverse("Hello world", 12, false, NULL);
-	h2 = isc_hash_function_reverse("heLLo WorLd", 12, false, NULL);
-
-	assert_int_equal(h1, h2);
-
-	/* Unequal */
-	h1 = isc_hash_function_reverse("Hello world", 12, true, NULL);
-	h2 = isc_hash_function_reverse("heLLo WorLd", 12, true, NULL);
-
-	assert_true(h1 != h2);
-}
-
 /* Hash function initializer test */
 static void
 isc_hash_initializer_test(void **state) {
@@ -144,15 +80,15 @@ isc_hash_initializer_test(void **state) {
 
 	UNUSED(state);
 
-	h1 = isc_hash_function("Hello world", 12, true, NULL);
-	h2 = isc_hash_function("Hello world", 12, true, NULL);
+	h1 = isc_hash_function("Hello world", 12, true);
+	h2 = isc_hash_function("Hello world", 12, true);
 
 	assert_int_equal(h1, h2);
 
 	isc_hash_set_initializer(isc_hash_get_initializer());
 
 	/* Hash value must not change */
-	h2 = isc_hash_function("Hello world", 12, true, NULL);
+	h2 = isc_hash_function("Hello world", 12, true);
 
 	assert_int_equal(h1, h2);
 }
@@ -161,7 +97,6 @@ int
 main(void) {
 	const struct CMUnitTest tests[] = {
 		cmocka_unit_test(isc_hash_function_test),
-		cmocka_unit_test(isc_hash_function_reverse_test),
 		cmocka_unit_test(isc_hash_initializer_test),
 	};
 
diff --git a/lib/isc/tests/siphash_test.c b/lib/isc/tests/siphash_test.c
new file mode 100644
index 0000000000..58baa89ab9
--- /dev/null
+++ b/lib/isc/tests/siphash_test.c
@@ -0,0 +1,130 @@
+/*
+ * Copyright (C) Internet Systems Consortium, Inc. ("ISC")
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * See the COPYRIGHT file distributed with this work for additional
+ * information regarding copyright ownership.
+ */
+
+#include <config.h>
+
+#if HAVE_CMOCKA
+
+#include <stdarg.h>
+#include <stddef.h>
+#include <setjmp.h>
+
+#include <stdlib.h>
+
+#define UNIT_TESTING
+#include <cmocka.h>
+
+#include <isc/siphash.h>
+
+#include "../siphash.c"
+
+const uint8_t vectors[64][8] = {
+    { 0x31, 0x0e, 0x0e, 0xdd, 0x47, 0xdb, 0x6f, 0x72, },
+    { 0xfd, 0x67, 0xdc, 0x93, 0xc5, 0x39, 0xf8, 0x74, },
+    { 0x5a, 0x4f, 0xa9, 0xd9, 0x09, 0x80, 0x6c, 0x0d, },
+    { 0x2d, 0x7e, 0xfb, 0xd7, 0x96, 0x66, 0x67, 0x85, },
+    { 0xb7, 0x87, 0x71, 0x27, 0xe0, 0x94, 0x27, 0xcf, },
+    { 0x8d, 0xa6, 0x99, 0xcd, 0x64, 0x55, 0x76, 0x18, },
+    { 0xce, 0xe3, 0xfe, 0x58, 0x6e, 0x46, 0xc9, 0xcb, },
+    { 0x37, 0xd1, 0x01, 0x8b, 0xf5, 0x00, 0x02, 0xab, },
+    { 0x62, 0x24, 0x93, 0x9a, 0x79, 0xf5, 0xf5, 0x93, },
+    { 0xb0, 0xe4, 0xa9, 0x0b, 0xdf, 0x82, 0x00, 0x9e, },
+    { 0xf3, 0xb9, 0xdd, 0x94, 0xc5, 0xbb, 0x5d, 0x7a, },
+    { 0xa7, 0xad, 0x6b, 0x22, 0x46, 0x2f, 0xb3, 0xf4, },
+    { 0xfb, 0xe5, 0x0e, 0x86, 0xbc, 0x8f, 0x1e, 0x75, },
+    { 0x90, 0x3d, 0x84, 0xc0, 0x27, 0x56, 0xea, 0x14, },
+    { 0xee, 0xf2, 0x7a, 0x8e, 0x90, 0xca, 0x23, 0xf7, },
+    { 0xe5, 0x45, 0xbe, 0x49, 0x61, 0xca, 0x29, 0xa1, },
+    { 0xdb, 0x9b, 0xc2, 0x57, 0x7f, 0xcc, 0x2a, 0x3f, },
+    { 0x94, 0x47, 0xbe, 0x2c, 0xf5, 0xe9, 0x9a, 0x69, },
+    { 0x9c, 0xd3, 0x8d, 0x96, 0xf0, 0xb3, 0xc1, 0x4b, },
+    { 0xbd, 0x61, 0x79, 0xa7, 0x1d, 0xc9, 0x6d, 0xbb, },
+    { 0x98, 0xee, 0xa2, 0x1a, 0xf2, 0x5c, 0xd6, 0xbe, },
+    { 0xc7, 0x67, 0x3b, 0x2e, 0xb0, 0xcb, 0xf2, 0xd0, },
+    { 0x88, 0x3e, 0xa3, 0xe3, 0x95, 0x67, 0x53, 0x93, },
+    { 0xc8, 0xce, 0x5c, 0xcd, 0x8c, 0x03, 0x0c, 0xa8, },
+    { 0x94, 0xaf, 0x49, 0xf6, 0xc6, 0x50, 0xad, 0xb8, },
+    { 0xea, 0xb8, 0x85, 0x8a, 0xde, 0x92, 0xe1, 0xbc, },
+    { 0xf3, 0x15, 0xbb, 0x5b, 0xb8, 0x35, 0xd8, 0x17, },
+    { 0xad, 0xcf, 0x6b, 0x07, 0x63, 0x61, 0x2e, 0x2f, },
+    { 0xa5, 0xc9, 0x1d, 0xa7, 0xac, 0xaa, 0x4d, 0xde, },
+    { 0x71, 0x65, 0x95, 0x87, 0x66, 0x50, 0xa2, 0xa6, },
+    { 0x28, 0xef, 0x49, 0x5c, 0x53, 0xa3, 0x87, 0xad, },
+    { 0x42, 0xc3, 0x41, 0xd8, 0xfa, 0x92, 0xd8, 0x32, },
+    { 0xce, 0x7c, 0xf2, 0x72, 0x2f, 0x51, 0x27, 0x71, },
+    { 0xe3, 0x78, 0x59, 0xf9, 0x46, 0x23, 0xf3, 0xa7, },
+    { 0x38, 0x12, 0x05, 0xbb, 0x1a, 0xb0, 0xe0, 0x12, },
+    { 0xae, 0x97, 0xa1, 0x0f, 0xd4, 0x34, 0xe0, 0x15, },
+    { 0xb4, 0xa3, 0x15, 0x08, 0xbe, 0xff, 0x4d, 0x31, },
+    { 0x81, 0x39, 0x62, 0x29, 0xf0, 0x90, 0x79, 0x02, },
+    { 0x4d, 0x0c, 0xf4, 0x9e, 0xe5, 0xd4, 0xdc, 0xca, },
+    { 0x5c, 0x73, 0x33, 0x6a, 0x76, 0xd8, 0xbf, 0x9a, },
+    { 0xd0, 0xa7, 0x04, 0x53, 0x6b, 0xa9, 0x3e, 0x0e, },
+    { 0x92, 0x59, 0x58, 0xfc, 0xd6, 0x42, 0x0c, 0xad, },
+    { 0xa9, 0x15, 0xc2, 0x9b, 0xc8, 0x06, 0x73, 0x18, },
+    { 0x95, 0x2b, 0x79, 0xf3, 0xbc, 0x0a, 0xa6, 0xd4, },
+    { 0xf2, 0x1d, 0xf2, 0xe4, 0x1d, 0x45, 0x35, 0xf9, },
+    { 0x87, 0x57, 0x75, 0x19, 0x04, 0x8f, 0x53, 0xa9, },
+    { 0x10, 0xa5, 0x6c, 0xf5, 0xdf, 0xcd, 0x9a, 0xdb, },
+    { 0xeb, 0x75, 0x09, 0x5c, 0xcd, 0x98, 0x6c, 0xd0, },
+    { 0x51, 0xa9, 0xcb, 0x9e, 0xcb, 0xa3, 0x12, 0xe6, },
+    { 0x96, 0xaf, 0xad, 0xfc, 0x2c, 0xe6, 0x66, 0xc7, },
+    { 0x72, 0xfe, 0x52, 0x97, 0x5a, 0x43, 0x64, 0xee, },
+    { 0x5a, 0x16, 0x45, 0xb2, 0x76, 0xd5, 0x92, 0xa1, },
+    { 0xb2, 0x74, 0xcb, 0x8e, 0xbf, 0x87, 0x87, 0x0a, },
+    { 0x6f, 0x9b, 0xb4, 0x20, 0x3d, 0xe7, 0xb3, 0x81, },
+    { 0xea, 0xec, 0xb2, 0xa3, 0x0b, 0x22, 0xa8, 0x7f, },
+    { 0x99, 0x24, 0xa4, 0x3c, 0xc1, 0x31, 0x57, 0x24, },
+    { 0xbd, 0x83, 0x8d, 0x3a, 0xaf, 0xbf, 0x8d, 0xb7, },
+    { 0x0b, 0x1a, 0x2a, 0x32, 0x65, 0xd5, 0x1a, 0xea, },
+    { 0x13, 0x50, 0x79, 0xa3, 0x23, 0x1c, 0xe6, 0x60, },
+    { 0x93, 0x2b, 0x28, 0x46, 0xe4, 0xd7, 0x06, 0x66, },
+    { 0xe1, 0x91, 0x5f, 0x5c, 0xb1, 0xec, 0xa4, 0x6c, },
+    { 0xf3, 0x25, 0x96, 0x5c, 0xa1, 0x6d, 0x62, 0x9f, },
+    { 0x57, 0x5f, 0xf2, 0x8e, 0x60, 0x38, 0x1b, 0xe5, },
+    { 0x72, 0x45, 0x06, 0xeb, 0x4c, 0x32, 0x8a, 0x95, },
+};
+
+static void
+isc_siphash24_test(void **state) {
+	UNUSED(state);
+
+	uint8_t in[64], out[8], key[16];
+	for (int i = 0; i < 16; i++) {
+		key[i] = i;
+	}
+
+	for (int i = 0; i < 64; i++) {
+		in[i] = i;
+		isc_siphash24(key, in, i, out);
+		assert_memory_equal(out, vectors[i], 8);
+	}
+}
+
+int main(void) {
+	const struct CMUnitTest tests[] = {
+		cmocka_unit_test(isc_siphash24_test),
+	};
+
+	return (cmocka_run_group_tests(tests, NULL, NULL));
+}
+
+#else /* HAVE_CMOCKA */
+
+#include <stdio.h>
+
+int
+main(void) {
+	printf("1..0 # Skipped: cmocka not available\n");
+	return (0);
+}
+
+#endif
diff --git a/lib/isc/win32/libisc.def.in b/lib/isc/win32/libisc.def.in
index 4b66b3c9c1..82a5c2b619 100644
--- a/lib/isc/win32/libisc.def.in
+++ b/lib/isc/win32/libisc.def.in
@@ -235,7 +235,6 @@ isc_fsaccess_changeowner
 isc_fsaccess_remove
 isc_fsaccess_set
 isc_hash_function
-isc_hash_function_reverse
 isc_hash_get_initializer
 isc_hash_set_initializer
 isc_heap_create
@@ -502,6 +501,7 @@ isc_serial_gt
 isc_serial_le
 isc_serial_lt
 isc_serial_ne
+isc_siphash24
 isc_sockaddr_any
 isc_sockaddr_any6
 isc_sockaddr_anyofpf
diff --git a/lib/isc/win32/libisc.vcxproj.filters.in b/lib/isc/win32/libisc.vcxproj.filters.in
index b58ff4f1a1..c030e90c0b 100644
--- a/lib/isc/win32/libisc.vcxproj.filters.in
+++ b/lib/isc/win32/libisc.vcxproj.filters.in
@@ -212,6 +212,9 @@
     <ClInclude Include="..\include\isc\serial.h">
       <Filter>Library Header Files</Filter>
     </ClInclude>
+    <ClInclude Include="..\include\isc\siphash.h">
+      <Filter>Library Header Files</Filter>
+    </ClInclude>
     <ClInclude Include="..\include\isc\sockaddr.h">
       <Filter>Library Header Files</Filter>
     </ClInclude>
@@ -583,6 +586,9 @@
     <ClCompile Include="..\serial.c">
       <Filter>Library Source Files</Filter>
     </ClCompile>
+    <ClCompile Include="..\siphash.c">
+      <Filter>Library Source Files</Filter>
+    </ClCompile>
     <ClCompile Include="..\sockaddr.c">
       <Filter>Library Source Files</Filter>
     </ClCompile>
diff --git a/lib/isc/win32/libisc.vcxproj.in b/lib/isc/win32/libisc.vcxproj.in
index 01d3ba2699..e6ef9ed7fb 100644
--- a/lib/isc/win32/libisc.vcxproj.in
+++ b/lib/isc/win32/libisc.vcxproj.in
@@ -353,6 +353,7 @@ copy InstallFiles ..\Build\Release\
     <ClInclude Include="..\include\isc\rwlock.h" />
     <ClInclude Include="..\include\isc\safe.h" />
     <ClInclude Include="..\include\isc\serial.h" />
+    <ClInclude Include="..\include\isc\siphash.h" />
     <ClInclude Include="..\include\isc\sockaddr.h" />
     <ClInclude Include="..\include\isc\socket.h" />
     <ClInclude Include="..\include\isc\stats.h" />
@@ -455,6 +456,7 @@ copy InstallFiles ..\Build\Release\
     <ClCompile Include="..\result.c" />
     <ClCompile Include="..\rwlock.c" />
     <ClCompile Include="..\serial.c" />
+    <ClCompile Include="..\siphash.c" />
     <ClCompile Include="..\sockaddr.c" />
     <ClCompile Include="..\stats.c" />
     <ClCompile Include="..\string.c" />
diff --git a/lib/isccfg/namedconf.c b/lib/isccfg/namedconf.c
index ce418c9b08..a5724fed7e 100644
--- a/lib/isccfg/namedconf.c
+++ b/lib/isccfg/namedconf.c
@@ -896,7 +896,7 @@ static cfg_type_t cfg_type_bracketed_portlist = {
 	&cfg_rep_list, &cfg_type_portrange
 };
 
-static const char *cookiealg_enums[] = { "aes", "sha1", "sha256", NULL };
+static const char *cookiealg_enums[] = { "aes", "sha1", "sha256", "siphash24", NULL };
 static cfg_type_t cfg_type_cookiealg = {
 	"cookiealg", cfg_parse_enum, cfg_print_ustring, cfg_doc_enum,
 	&cfg_rep_string, &cookiealg_enums
diff --git a/lib/ns/client.c b/lib/ns/client.c
index 9138c4bdd1..2be462a518 100644
--- a/lib/ns/client.c
+++ b/lib/ns/client.c
@@ -27,6 +27,7 @@
 #include <isc/random.h>
 #include <isc/safe.h>
 #include <isc/serial.h>
+#include <isc/siphash.h>
 #include <isc/stats.h>
 #include <isc/stdio.h>
 #include <isc/string.h>
@@ -1921,23 +1922,63 @@ static void
 compute_cookie(ns_client_t *client, uint32_t when, uint32_t nonce,
 	       const unsigned char *secret, isc_buffer_t *buf)
 {
+	unsigned char digest[ISC_MAX_MD_SIZE] ISC_NONSTRING = { 0 };
+	STATIC_ASSERT(ISC_MAX_MD_SIZE >= ISC_SIPHASH24_TAG_LENGTH,
+		      "You need to increase the digest buffer.");
+	STATIC_ASSERT(ISC_MAX_MD_SIZE >= ISC_AES_BLOCK_LENGTH,
+		      "You need to increase the digest buffer.");
+
 	switch (client->sctx->cookiealg) {
+	case ns_cookiealg_siphash24: {
+		unsigned char input[16 + 16] ISC_NONSTRING = { 0 };
+		size_t inputlen = 0;
+		isc_netaddr_t netaddr;
+		unsigned char *cp;
+
+		cp = isc_buffer_used(buf);
+		isc_buffer_putmem(buf, client->cookie, 8);
+		isc_buffer_putuint8(buf, NS_COOKIE_VERSION_1);
+		isc_buffer_putuint24(buf, 0); /* Reserved */
+		isc_buffer_putuint32(buf, when);
+
+		memmove(input, cp, 16);
+
+		isc_netaddr_fromsockaddr(&netaddr, &client->peeraddr);
+		switch (netaddr.family) {
+		case AF_INET:
+			cp = (unsigned char *)&netaddr.type.in;
+			memmove(input + 16, cp, 4);
+			inputlen = 20;
+			break;
+		case AF_INET6:
+			cp = (unsigned char *)&netaddr.type.in6;
+			memmove(input + 16, cp, 16);
+			inputlen = 32;
+			break;
+		default:
+			INSIST(0);
+			ISC_UNREACHABLE();
+		}
+
+		isc_siphash24(secret, input, inputlen, digest);
+		isc_buffer_putmem(buf, digest, 8);
+		break;
+	}
 	case ns_cookiealg_aes: {
-		unsigned char digest[ISC_AES_BLOCK_LENGTH];
-		unsigned char input[4 + 4 + 16];
+		unsigned char input[4 + 4 + 16] ISC_NONSTRING = { 0 };
 		isc_netaddr_t netaddr;
 		unsigned char *cp;
 		unsigned int i;
 
-		memset(input, 0, sizeof(input));
 		cp = isc_buffer_used(buf);
 		isc_buffer_putmem(buf, client->cookie, 8);
 		isc_buffer_putuint32(buf, nonce);
 		isc_buffer_putuint32(buf, when);
 		memmove(input, cp, 16);
 		isc_aes128_crypt(secret, input, digest);
-		for (i = 0; i < 8; i++)
+		for (i = 0; i < 8; i++) {
 			input[i] = digest[i] ^ digest[i + 8];
+		}
 		isc_netaddr_fromsockaddr(&netaddr, &client->peeraddr);
 		switch (netaddr.family) {
 		case AF_INET:
@@ -1950,21 +1991,25 @@ compute_cookie(ns_client_t *client, uint32_t when, uint32_t nonce,
 			cp = (unsigned char *)&netaddr.type.in6;
 			memmove(input + 8, cp, 16);
 			isc_aes128_crypt(secret, input, digest);
-			for (i = 0; i < 8; i++)
+			for (i = 0; i < 8; i++) {
 				input[i + 8] = digest[i] ^ digest[i + 8];
+			}
 			isc_aes128_crypt(client->sctx->secret, input + 8,
 					 digest);
 			break;
+		default:
+			INSIST(0);
+			ISC_UNREACHABLE();
 		}
-		for (i = 0; i < 8; i++)
+		for (i = 0; i < 8; i++) {
 			digest[i] ^= digest[i + 8];
+		}
 		isc_buffer_putmem(buf, digest, 8);
 		break;
 	}
 
 	case ns_cookiealg_sha1:
 	case ns_cookiealg_sha256: {
-		unsigned char digest[ISC_MAX_MD_SIZE];
 		unsigned char input[8 + 4 + 4 + 16];
 		isc_netaddr_t netaddr;
 		unsigned char *cp;
diff --git a/lib/ns/include/ns/types.h b/lib/ns/include/ns/types.h
index 0c70332966..c7d75f908f 100644
--- a/lib/ns/include/ns/types.h
+++ b/lib/ns/include/ns/types.h
@@ -29,7 +29,10 @@ typedef struct ns_stats			ns_stats_t;
 typedef enum {
 	ns_cookiealg_aes,
 	ns_cookiealg_sha1,
-	ns_cookiealg_sha256
+	ns_cookiealg_sha256,
+	ns_cookiealg_siphash24
 } ns_cookiealg_t;
 
+#define NS_COOKIE_VERSION_1 1
+
 #endif /* NS_TYPES_H */
diff --git a/util/copyrights b/util/copyrights
index 2f47ad9ce1..7ffb6c15b8 100644
--- a/util/copyrights
+++ b/util/copyrights
@@ -2203,6 +2203,7 @@
 ./lib/isc/include/isc/counter.h			C	2014,2016,2018,2019
 ./lib/isc/include/isc/crc64.h			C	2013,2016,2018,2019
 ./lib/isc/include/isc/deprecated.h		C	2017,2018,2019
+./lib/isc/include/isc/endian.h			C	2019
 ./lib/isc/include/isc/errno.h			C	2016,2018,2019
 ./lib/isc/include/isc/error.h			C	1998,1999,2000,2001,2004,2005,2006,2007,2009,2016,2017,2018,2019
 ./lib/isc/include/isc/event.h			C	1998,1999,2000,2001,2002,2004,2005,2006,2007,2014,2016,2017,2018,2019
@@ -2255,6 +2256,7 @@
 ./lib/isc/include/isc/rwlock.h			C	1998,1999,2000,2001,2003,2004,2005,2006,2007,2016,2017,2018,2019
 ./lib/isc/include/isc/safe.h			C	2013,2015,2016,2017,2018,2019
 ./lib/isc/include/isc/serial.h			C	1999,2000,2001,2004,2005,2006,2007,2009,2016,2018,2019
+./lib/isc/include/isc/siphash.h			C	2019
 ./lib/isc/include/isc/sockaddr.h		C	1998,1999,2000,2001,2002,2003,2004,2005,2006,2007,2009,2012,2015,2016,2018,2019
 ./lib/isc/include/isc/socket.h			C	1998,1999,2000,2001,2002,2004,2005,2006,2007,2008,2009,2011,2012,2013,2014,2016,2018,2019
 ./lib/isc/include/isc/stats.h			C	2009,2012,2016,2018,2019
@@ -2315,6 +2317,7 @@
 ./lib/isc/result.c				C	1998,1999,2000,2001,2003,2004,2005,2007,2008,2012,2014,2015,2016,2017,2018,2019
 ./lib/isc/rwlock.c				C	1998,1999,2000,2001,2003,2004,2005,2007,2009,2011,2012,2015,2016,2017,2018,2019
 ./lib/isc/serial.c				C	1999,2000,2001,2004,2005,2007,2016,2018,2019
+./lib/isc/siphash.c				C	2019
 ./lib/isc/sockaddr.c				C	1999,2000,2001,2002,2003,2004,2005,2006,2007,2010,2011,2012,2014,2015,2016,2017,2018,2019
 ./lib/isc/stats.c				C	2009,2012,2013,2014,2015,2016,2017,2018,2019
 ./lib/isc/string.c				C	1999,2000,2001,2003,2004,2005,2006,2007,2011,2012,2014,2015,2016,2018,2019
@@ -2347,6 +2350,7 @@
 ./lib/isc/tests/regex_test.c			C	2013,2015,2016,2018,2019
 ./lib/isc/tests/result_test.c			C	2015,2016,2018,2019
 ./lib/isc/tests/safe_test.c			C	2013,2015,2016,2017,2018,2019
+./lib/isc/tests/siphash_test.c			C	2019
 ./lib/isc/tests/sockaddr_test.c			C	2012,2015,2016,2017,2018,2019
 ./lib/isc/tests/socket_test.c			C	2011,2012,2013,2014,2015,2016,2017,2018,2019
 ./lib/isc/tests/symtab_test.c			C	2011,2012,2013,2016,2018,2019
diff --git a/win32utils/Configure b/win32utils/Configure
index 36d2f8fb98..1941f2e2d1 100644
--- a/win32utils/Configure
+++ b/win32utils/Configure
@@ -192,8 +192,7 @@ my @projectlist = ("..\\bin\\check\\win32\\checkconf.vcxproj",
 
 my %configdefh;
 
-my @substdefh = ("AES_CC",
-                 "CONFIGARGS",
+my @substdefh = ("CONFIGARGS",
                  "DNS_RDATASET_FIXED",
                  "HAVE_GEOIP",
                  "HAVE_GEOIP2",
@@ -212,8 +211,6 @@ my @substdefh = ("AES_CC",
                  "HAVE_PKCS11_ED448",
                  "HAVE_READLINE",
                  "HAVE_ZLIB",
-                 "HMAC_SHA1_CC",
-                 "HMAC_SHA256_CC",
                  "ISC_LIST_CHECKINIT",
                  "TUNE_LARGE",
                  "WANT_QUERYTRACE",
@@ -1622,18 +1619,6 @@ if ($use_openssl eq "no") {
     }
 }
 
-# with-cc-alg
-if ($cookie_algorithm eq "aes") {
-    $configdefh{"AES_CC"} = 1;
-}
-if ($cookie_algorithm eq "sha1") {
-    $configdefh{"HMAC_SHA1_CC"} = 1;
-} elsif ($cookie_algorithm eq "sha256") {
-    $configdefh{"HMAC_SHA256_CC"} = 1;
-} elsif ($cookie_algorithm ne "aes") {
-    die "Unrecognized cookie algorithm: $cookie_algorithm\n";
-}
-
 if ($cryptolib ne "") {
     print "Cryptographic library for DNSSEC: $cryptolib\n";
 } else {