build: require boost >= 1.71.0

Refs: #5276
Change-Id: Ifc719cf5e4b8704e0408cab1f9ab849006061dfc
diff --git a/tests/unit-tests/crypto-helpers.t.cpp b/tests/unit-tests/crypto-helpers.t.cpp
index ff645dd..f8ec1a4 100644
--- a/tests/unit-tests/crypto-helpers.t.cpp
+++ b/tests/unit-tests/crypto-helpers.t.cpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
 /*
- * Copyright (c) 2017-2022, Regents of the University of California.
+ * Copyright (c) 2017-2023, Regents of the University of California.
  *
  * This file is part of ndncert, a certificate management system based on NDN.
  *
@@ -22,6 +22,8 @@
 
 #include "tests/boost-test.hpp"
 
+#include <boost/endian/conversion.hpp>
+
 namespace ndncert::tests {
 
 BOOST_AUTO_TEST_SUITE(TestCryptoHelpers)
@@ -271,6 +273,8 @@
 
 BOOST_AUTO_TEST_CASE(AesIV)
 {
+  namespace be = boost::endian;
+
   const uint8_t key[] = {0xbc, 0x22, 0xf3, 0xf0, 0x5c, 0xc4, 0x0d, 0xb9,
                          0x31, 0x1e, 0x41, 0x92, 0x96, 0x6f, 0xee, 0x92};
   const std::string plaintext = "alongstringalongstringalongstringalongstringalongstringalongstringalongstringalongstring";
@@ -282,8 +286,8 @@
   auto ivBlock = block.get(tlv::InitializationVector);
   ndn::Buffer ivBuf(ivBlock.value(), ivBlock.value_size());
   BOOST_CHECK_EQUAL(ivBuf.size(), 12);
-  BOOST_CHECK_EQUAL(loadBigU32(&encryptionIv[8]), 6);
-  BOOST_CHECK_EQUAL(loadBigU32(&ivBuf[8]), 0);
+  BOOST_CHECK_EQUAL((be::endian_load<uint32_t, 4, be::order::big>(&encryptionIv[8])), 6);
+  BOOST_CHECK_EQUAL((be::endian_load<uint32_t, 4, be::order::big>(&ivBuf[8])), 0);
 
   block = encodeBlockWithAesGcm128(ndn::tlv::ApplicationParameters, key, (uint8_t*)plaintext.c_str(), plaintext.size(),
                                    (uint8_t*)associatedData.c_str(), associatedData.size(), encryptionIv);