diff --git a/tests/unit/data.t.cpp b/tests/unit/data.t.cpp
index 9b530d6..5162f4d 100644
--- a/tests/unit/data.t.cpp
+++ b/tests/unit/data.t.cpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
 /*
- * Copyright (c) 2013-2022 Regents of the University of California.
+ * Copyright (c) 2013-2023 Regents of the University of California.
  *
  * This file is part of ndn-cxx library (NDN C++ library with eXperimental eXtensions).
  *
@@ -26,7 +26,6 @@
 #include "ndn-cxx/security/transform/signer-filter.hpp"
 #include "ndn-cxx/security/transform/step-source.hpp"
 #include "ndn-cxx/security/transform/stream-sink.hpp"
-#include "ndn-cxx/security/verification-helpers.hpp"
 #include "ndn-cxx/util/sha256.hpp"
 #include "ndn-cxx/util/string-helper.hpp"
 
@@ -113,50 +112,48 @@
   security::transform::PublicKey m_pubKey;
 
 private:
-  static const uint8_t PRIVATE_KEY_DER[632];
-};
-
-const uint8_t DataSigningKeyFixture::PRIVATE_KEY_DER[] = {
-  0x30, 0x82, 0x02, 0x74, 0x02, 0x01, 0x00, 0x30, 0x0d, 0x06, 0x09, 0x2a, 0x86, 0x48, 0x86, 0xf7,
-  0x0d, 0x01, 0x01, 0x01, 0x05, 0x00, 0x04, 0x82, 0x02, 0x5e, 0x30, 0x82, 0x02, 0x5a, 0x02, 0x01,
-  0x00, 0x02, 0x81, 0x81, 0x00, 0x9e, 0x06, 0x3e, 0x47, 0x85, 0xb2, 0x34, 0x37, 0xaa, 0x85, 0x47,
-  0xac, 0x03, 0x24, 0x83, 0xb5, 0x9c, 0xa8, 0x05, 0x3a, 0x24, 0x1e, 0xeb, 0x89, 0x01, 0xbb, 0xe9,
-  0x9b, 0xb2, 0xc3, 0x22, 0xac, 0x68, 0xe3, 0xf0, 0x6c, 0x02, 0xce, 0x68, 0xa6, 0xc4, 0xd0, 0xa7,
-  0x06, 0x90, 0x9c, 0xaa, 0x1b, 0x08, 0x1d, 0x8b, 0x43, 0x9a, 0x33, 0x67, 0x44, 0x6d, 0x21, 0xa3,
-  0x1b, 0x88, 0x9a, 0x97, 0x5e, 0x59, 0xc4, 0x15, 0x0b, 0xd9, 0x2c, 0xbd, 0x51, 0x07, 0x61, 0x82,
-  0xad, 0xc1, 0xb8, 0xd7, 0xbf, 0x9b, 0xcf, 0x7d, 0x24, 0xc2, 0x63, 0xf3, 0x97, 0x17, 0xeb, 0xfe,
-  0x62, 0x25, 0xba, 0x5b, 0x4d, 0x8a, 0xc2, 0x7a, 0xbd, 0x43, 0x8a, 0x8f, 0xb8, 0xf2, 0xf1, 0xc5,
-  0x6a, 0x30, 0xd3, 0x50, 0x8c, 0xc8, 0x9a, 0xdf, 0xef, 0xed, 0x35, 0xe7, 0x7a, 0x62, 0xea, 0x76,
-  0x7c, 0xbb, 0x08, 0x26, 0xc7, 0x02, 0x01, 0x11, 0x02, 0x81, 0x80, 0x04, 0xa5, 0xd4, 0xa7, 0xc0,
-  0x2a, 0xe3, 0x6b, 0x0c, 0x8b, 0x73, 0x0c, 0x96, 0xae, 0x40, 0x1b, 0xee, 0x04, 0xf1, 0x18, 0x4c,
-  0x5b, 0x43, 0x29, 0xad, 0x3a, 0x3b, 0x93, 0xa3, 0x60, 0x17, 0x9b, 0xa8, 0xbb, 0x68, 0xf4, 0x1e,
-  0x33, 0x3f, 0x50, 0x32, 0xf7, 0x13, 0xf8, 0xa9, 0xe6, 0x7d, 0x79, 0x44, 0x00, 0xde, 0x72, 0xed,
-  0xf2, 0x73, 0xfa, 0x7b, 0xae, 0x2a, 0x71, 0xc0, 0x40, 0xc8, 0x37, 0x6f, 0x38, 0xb2, 0x69, 0x1f,
-  0xa8, 0x83, 0x7b, 0x42, 0x00, 0x73, 0x46, 0xe6, 0x4c, 0x91, 0x7f, 0x13, 0x06, 0x69, 0x06, 0xd8,
-  0x3f, 0x22, 0x15, 0x75, 0xf6, 0xde, 0xcd, 0xb0, 0xbc, 0x66, 0x61, 0x91, 0x08, 0x9b, 0x2b, 0xb2,
-  0x00, 0xa9, 0x67, 0x05, 0x39, 0x40, 0xb9, 0x37, 0x85, 0x88, 0x4f, 0x76, 0x79, 0x63, 0xc0, 0x88,
-  0x3c, 0x86, 0xa8, 0x12, 0x94, 0x5f, 0xe4, 0x36, 0x3d, 0xea, 0xb9, 0x02, 0x41, 0x00, 0xb6, 0x2e,
-  0xbb, 0xcd, 0x2f, 0x3a, 0x99, 0xe0, 0xa1, 0xa5, 0x44, 0x77, 0xea, 0x0b, 0xbe, 0x16, 0x95, 0x0e,
-  0x64, 0xa7, 0x68, 0xd7, 0x4b, 0x15, 0x15, 0x23, 0xe2, 0x1e, 0x4e, 0x00, 0x2c, 0x22, 0x97, 0xae,
-  0xb0, 0x74, 0xa6, 0x99, 0xd0, 0x5d, 0xb7, 0x1b, 0x10, 0x34, 0x13, 0xd2, 0x5f, 0x6e, 0x56, 0xad,
-  0x85, 0x4a, 0xdb, 0xf0, 0x78, 0xbd, 0xf4, 0x8c, 0xb7, 0x9a, 0x3e, 0x99, 0xef, 0xb9, 0x02, 0x41,
-  0x00, 0xde, 0x0d, 0xa7, 0x48, 0x75, 0x90, 0xad, 0x11, 0xa1, 0xac, 0xee, 0xcb, 0x41, 0x81, 0xc6,
-  0xc8, 0x7f, 0xe7, 0x25, 0x94, 0xa1, 0x2a, 0x21, 0xa8, 0x57, 0xfe, 0x84, 0xf2, 0x5e, 0xb4, 0x96,
-  0x35, 0xaf, 0xef, 0x2e, 0x7a, 0xf8, 0xda, 0x3f, 0xac, 0x8a, 0x3c, 0x1c, 0x9c, 0xbd, 0x44, 0xd6,
-  0x90, 0xb5, 0xce, 0x1b, 0x12, 0xf9, 0x3b, 0x8c, 0x69, 0xf6, 0xa9, 0x02, 0x93, 0x48, 0x35, 0x0a,
-  0x7f, 0x02, 0x40, 0x6b, 0x2a, 0x8c, 0x96, 0xd0, 0x7c, 0xd2, 0xfc, 0x9b, 0x52, 0x28, 0x46, 0x89,
-  0xac, 0x8d, 0xef, 0x2a, 0x80, 0xef, 0xea, 0x01, 0x6f, 0x95, 0x93, 0xee, 0x51, 0x57, 0xd5, 0x97,
-  0x4b, 0x65, 0x41, 0x86, 0x66, 0xc2, 0x26, 0x80, 0x1e, 0x3e, 0x55, 0x3e, 0x88, 0x63, 0xe2, 0x66,
-  0x03, 0x47, 0x31, 0xd8, 0xa2, 0x4e, 0x68, 0x45, 0x24, 0x0a, 0xca, 0x17, 0x61, 0xd5, 0x69, 0xca,
-  0x78, 0xab, 0x21, 0x02, 0x41, 0x00, 0x8f, 0xae, 0x7b, 0x4d, 0x00, 0xc7, 0x06, 0x92, 0xf0, 0x24,
-  0x9a, 0x83, 0x84, 0xbd, 0x62, 0x81, 0xbc, 0x2c, 0x27, 0x60, 0x2c, 0x0c, 0x33, 0xe5, 0x66, 0x1d,
-  0x28, 0xd9, 0x10, 0x1a, 0x7f, 0x4f, 0xea, 0x4f, 0x78, 0x6d, 0xb0, 0x14, 0xbf, 0xc9, 0xff, 0x17,
-  0xd6, 0x47, 0x4d, 0x4a, 0xa8, 0xf4, 0x39, 0x67, 0x3e, 0xb1, 0xec, 0x8f, 0xf1, 0x71, 0xbd, 0xb8,
-  0xa7, 0x50, 0x3d, 0xc7, 0xf7, 0xbb, 0x02, 0x40, 0x0d, 0x85, 0x32, 0x73, 0x9f, 0x0a, 0x33, 0x2f,
-  0x4b, 0xa2, 0xbd, 0xd1, 0xb1, 0x42, 0xf0, 0x72, 0xa8, 0x7a, 0xc8, 0x15, 0x37, 0x1b, 0xde, 0x76,
-  0x70, 0xce, 0xfd, 0x69, 0x20, 0x00, 0x4d, 0xc9, 0x4f, 0x35, 0x6f, 0xd1, 0x35, 0xa1, 0x04, 0x95,
-  0x30, 0xe8, 0x3b, 0xd5, 0x03, 0x5a, 0x50, 0x21, 0x6d, 0xa0, 0x84, 0x39, 0xe9, 0x2e, 0x1e, 0xfc,
-  0xe4, 0x82, 0x43, 0x20, 0x46, 0x7d, 0x0a, 0xb6
+  static constexpr uint8_t PRIVATE_KEY_DER[] = {
+    0x30, 0x82, 0x02, 0x74, 0x02, 0x01, 0x00, 0x30, 0x0d, 0x06, 0x09, 0x2a, 0x86, 0x48, 0x86, 0xf7,
+    0x0d, 0x01, 0x01, 0x01, 0x05, 0x00, 0x04, 0x82, 0x02, 0x5e, 0x30, 0x82, 0x02, 0x5a, 0x02, 0x01,
+    0x00, 0x02, 0x81, 0x81, 0x00, 0x9e, 0x06, 0x3e, 0x47, 0x85, 0xb2, 0x34, 0x37, 0xaa, 0x85, 0x47,
+    0xac, 0x03, 0x24, 0x83, 0xb5, 0x9c, 0xa8, 0x05, 0x3a, 0x24, 0x1e, 0xeb, 0x89, 0x01, 0xbb, 0xe9,
+    0x9b, 0xb2, 0xc3, 0x22, 0xac, 0x68, 0xe3, 0xf0, 0x6c, 0x02, 0xce, 0x68, 0xa6, 0xc4, 0xd0, 0xa7,
+    0x06, 0x90, 0x9c, 0xaa, 0x1b, 0x08, 0x1d, 0x8b, 0x43, 0x9a, 0x33, 0x67, 0x44, 0x6d, 0x21, 0xa3,
+    0x1b, 0x88, 0x9a, 0x97, 0x5e, 0x59, 0xc4, 0x15, 0x0b, 0xd9, 0x2c, 0xbd, 0x51, 0x07, 0x61, 0x82,
+    0xad, 0xc1, 0xb8, 0xd7, 0xbf, 0x9b, 0xcf, 0x7d, 0x24, 0xc2, 0x63, 0xf3, 0x97, 0x17, 0xeb, 0xfe,
+    0x62, 0x25, 0xba, 0x5b, 0x4d, 0x8a, 0xc2, 0x7a, 0xbd, 0x43, 0x8a, 0x8f, 0xb8, 0xf2, 0xf1, 0xc5,
+    0x6a, 0x30, 0xd3, 0x50, 0x8c, 0xc8, 0x9a, 0xdf, 0xef, 0xed, 0x35, 0xe7, 0x7a, 0x62, 0xea, 0x76,
+    0x7c, 0xbb, 0x08, 0x26, 0xc7, 0x02, 0x01, 0x11, 0x02, 0x81, 0x80, 0x04, 0xa5, 0xd4, 0xa7, 0xc0,
+    0x2a, 0xe3, 0x6b, 0x0c, 0x8b, 0x73, 0x0c, 0x96, 0xae, 0x40, 0x1b, 0xee, 0x04, 0xf1, 0x18, 0x4c,
+    0x5b, 0x43, 0x29, 0xad, 0x3a, 0x3b, 0x93, 0xa3, 0x60, 0x17, 0x9b, 0xa8, 0xbb, 0x68, 0xf4, 0x1e,
+    0x33, 0x3f, 0x50, 0x32, 0xf7, 0x13, 0xf8, 0xa9, 0xe6, 0x7d, 0x79, 0x44, 0x00, 0xde, 0x72, 0xed,
+    0xf2, 0x73, 0xfa, 0x7b, 0xae, 0x2a, 0x71, 0xc0, 0x40, 0xc8, 0x37, 0x6f, 0x38, 0xb2, 0x69, 0x1f,
+    0xa8, 0x83, 0x7b, 0x42, 0x00, 0x73, 0x46, 0xe6, 0x4c, 0x91, 0x7f, 0x13, 0x06, 0x69, 0x06, 0xd8,
+    0x3f, 0x22, 0x15, 0x75, 0xf6, 0xde, 0xcd, 0xb0, 0xbc, 0x66, 0x61, 0x91, 0x08, 0x9b, 0x2b, 0xb2,
+    0x00, 0xa9, 0x67, 0x05, 0x39, 0x40, 0xb9, 0x37, 0x85, 0x88, 0x4f, 0x76, 0x79, 0x63, 0xc0, 0x88,
+    0x3c, 0x86, 0xa8, 0x12, 0x94, 0x5f, 0xe4, 0x36, 0x3d, 0xea, 0xb9, 0x02, 0x41, 0x00, 0xb6, 0x2e,
+    0xbb, 0xcd, 0x2f, 0x3a, 0x99, 0xe0, 0xa1, 0xa5, 0x44, 0x77, 0xea, 0x0b, 0xbe, 0x16, 0x95, 0x0e,
+    0x64, 0xa7, 0x68, 0xd7, 0x4b, 0x15, 0x15, 0x23, 0xe2, 0x1e, 0x4e, 0x00, 0x2c, 0x22, 0x97, 0xae,
+    0xb0, 0x74, 0xa6, 0x99, 0xd0, 0x5d, 0xb7, 0x1b, 0x10, 0x34, 0x13, 0xd2, 0x5f, 0x6e, 0x56, 0xad,
+    0x85, 0x4a, 0xdb, 0xf0, 0x78, 0xbd, 0xf4, 0x8c, 0xb7, 0x9a, 0x3e, 0x99, 0xef, 0xb9, 0x02, 0x41,
+    0x00, 0xde, 0x0d, 0xa7, 0x48, 0x75, 0x90, 0xad, 0x11, 0xa1, 0xac, 0xee, 0xcb, 0x41, 0x81, 0xc6,
+    0xc8, 0x7f, 0xe7, 0x25, 0x94, 0xa1, 0x2a, 0x21, 0xa8, 0x57, 0xfe, 0x84, 0xf2, 0x5e, 0xb4, 0x96,
+    0x35, 0xaf, 0xef, 0x2e, 0x7a, 0xf8, 0xda, 0x3f, 0xac, 0x8a, 0x3c, 0x1c, 0x9c, 0xbd, 0x44, 0xd6,
+    0x90, 0xb5, 0xce, 0x1b, 0x12, 0xf9, 0x3b, 0x8c, 0x69, 0xf6, 0xa9, 0x02, 0x93, 0x48, 0x35, 0x0a,
+    0x7f, 0x02, 0x40, 0x6b, 0x2a, 0x8c, 0x96, 0xd0, 0x7c, 0xd2, 0xfc, 0x9b, 0x52, 0x28, 0x46, 0x89,
+    0xac, 0x8d, 0xef, 0x2a, 0x80, 0xef, 0xea, 0x01, 0x6f, 0x95, 0x93, 0xee, 0x51, 0x57, 0xd5, 0x97,
+    0x4b, 0x65, 0x41, 0x86, 0x66, 0xc2, 0x26, 0x80, 0x1e, 0x3e, 0x55, 0x3e, 0x88, 0x63, 0xe2, 0x66,
+    0x03, 0x47, 0x31, 0xd8, 0xa2, 0x4e, 0x68, 0x45, 0x24, 0x0a, 0xca, 0x17, 0x61, 0xd5, 0x69, 0xca,
+    0x78, 0xab, 0x21, 0x02, 0x41, 0x00, 0x8f, 0xae, 0x7b, 0x4d, 0x00, 0xc7, 0x06, 0x92, 0xf0, 0x24,
+    0x9a, 0x83, 0x84, 0xbd, 0x62, 0x81, 0xbc, 0x2c, 0x27, 0x60, 0x2c, 0x0c, 0x33, 0xe5, 0x66, 0x1d,
+    0x28, 0xd9, 0x10, 0x1a, 0x7f, 0x4f, 0xea, 0x4f, 0x78, 0x6d, 0xb0, 0x14, 0xbf, 0xc9, 0xff, 0x17,
+    0xd6, 0x47, 0x4d, 0x4a, 0xa8, 0xf4, 0x39, 0x67, 0x3e, 0xb1, 0xec, 0x8f, 0xf1, 0x71, 0xbd, 0xb8,
+    0xa7, 0x50, 0x3d, 0xc7, 0xf7, 0xbb, 0x02, 0x40, 0x0d, 0x85, 0x32, 0x73, 0x9f, 0x0a, 0x33, 0x2f,
+    0x4b, 0xa2, 0xbd, 0xd1, 0xb1, 0x42, 0xf0, 0x72, 0xa8, 0x7a, 0xc8, 0x15, 0x37, 0x1b, 0xde, 0x76,
+    0x70, 0xce, 0xfd, 0x69, 0x20, 0x00, 0x4d, 0xc9, 0x4f, 0x35, 0x6f, 0xd1, 0x35, 0xa1, 0x04, 0x95,
+    0x30, 0xe8, 0x3b, 0xd5, 0x03, 0x5a, 0x50, 0x21, 0x6d, 0xa0, 0x84, 0x39, 0xe9, 0x2e, 0x1e, 0xfc,
+    0xe4, 0x82, 0x43, 0x20, 0x46, 0x7d, 0x0a, 0xb6,
+  };
 };
 
 BOOST_AUTO_TEST_SUITE(Encode)