diff --git a/tests/unit-tests/ca-module.t.cpp b/tests/unit-tests/ca-module.t.cpp
index 81a5916..13abf4b 100644
--- a/tests/unit-tests/ca-module.t.cpp
+++ b/tests/unit-tests/ca-module.t.cpp
@@ -40,7 +40,7 @@
 {
   util::DummyClientFace face(io, {true, true});
   CaModule ca(face, m_keyChain, "tests/unit-tests/ca.conf.test", "ca-storage-memory");
-  BOOST_CHECK_EQUAL(ca.getCaConf().m_caName, "/ndn");
+  BOOST_CHECK_EQUAL(ca.getCaConf().m_caPrefix, "/ndn");
 
   auto identity = addIdentity(Name("/ndn/site2"));
   auto key = identity.getDefaultKey();
@@ -61,23 +61,27 @@
 
   util::DummyClientFace face(io, {true, true});
   CaModule ca(face, m_keyChain, "tests/unit-tests/ca.conf.test", "ca-storage-memory");
-  ca.setProbeHandler([&] (const JsonSection& probeInfo) {
+  ca.setProbeHandler([&] (const Block& probeInfo) {
       return "example";
     });
   advanceClocks(time::milliseconds(20), 60);
 
   Interest interest("/ndn/CA/PROBE");
   interest.setCanBePrefix(false);
-  JsonSection paramJson;
-  paramJson.add(JSON_CLIENT_PROBE_INFO, "zhiyi");
-  interest.setApplicationParameters(ClientModule::paramFromJson(paramJson));
+
+  Block paramTLV = makeEmptyBlock(tlv::ApplicationParameters);
+  paramTLV.push_back(makeStringBlock(tlv_parameter_key, JSON_CLIENT_PROBE_INFO));
+  paramTLV.push_back(makeStringBlock(tlv_parameter_value, "zhiyi"));
+  paramTLV.encode();
+  interest.setApplicationParameters(paramTLV);
 
   int count = 0;
   face.onSendData.connect([&] (const Data& response) {
       count++;
       BOOST_CHECK(security::verifySignature(response, cert));
-      auto contentJson = ClientModule::getJsonFromData(response);
-      BOOST_CHECK_EQUAL(contentJson.get<std::string>(JSON_CA_NAME), "/ndn/example");
+      Block contentBlock = response.getContent();
+      contentBlock.parse();
+      BOOST_CHECK_EQUAL(readString(contentBlock.get(tlv_ca_prefix)), "/ndn/example");
     });
   face.receive(interest);
 
@@ -93,7 +97,7 @@
 
   util::DummyClientFace face(io, {true, true});
   CaModule ca(face, m_keyChain, "tests/unit-tests/ca.conf.test", "ca-storage-memory");
-  ca.setProbeHandler([&] (const JsonSection& probeInfo) {
+  ca.setProbeHandler([&] (const Block& probeInfo) {
       return "example";
     });
   advanceClocks(time::milliseconds(20), 60);
@@ -287,7 +291,7 @@
       auto contentJson = ClientModule::getJsonFromData(response);
       client.onNewResponse(response);
       auto paramJson = pinChallenge.getRequirementForChallenge(client.m_status, client.m_challengeStatus);
-      challengeInterest = client.generateChallengeInterest(pinChallenge.genChallengeRequestJson(client.m_status,
+      challengeInterest = client.generateChallengeInterest(pinChallenge.genChallengeRequestTLV(client.m_status,
                                                                                                 client.m_challengeStatus,
                                                                                                 paramJson));
     }
@@ -300,7 +304,7 @@
       BOOST_CHECK_EQUAL(client.m_challengeStatus, ChallengePin::NEED_CODE);
 
       auto paramJson = pinChallenge.getRequirementForChallenge(client.m_status, client.m_challengeStatus);
-      challengeInterest2 = client.generateChallengeInterest(pinChallenge.genChallengeRequestJson(client.m_status,
+      challengeInterest2 = client.generateChallengeInterest(pinChallenge.genChallengeRequestTLV(client.m_status,
                                                                                                  client.m_challengeStatus,
                                                                                                  paramJson));
     }
@@ -319,7 +323,7 @@
         if (i.first == ChallengePin::JSON_PIN_CODE)
           i.second.put("", secret);
       }
-      challengeInterest3 = client.generateChallengeInterest(pinChallenge.genChallengeRequestJson(client.m_status,
+      challengeInterest3 = client.generateChallengeInterest(pinChallenge.genChallengeRequestTLV(client.m_status,
                                                                                                  client.m_challengeStatus,
                                                                                                  paramJson));
     }
diff --git a/tests/unit-tests/challenge-credential.t.cpp b/tests/unit-tests/challenge-credential.t.cpp
index 2455e73..9072fa0 100644
--- a/tests/unit-tests/challenge-credential.t.cpp
+++ b/tests/unit-tests/challenge-credential.t.cpp
@@ -78,19 +78,22 @@
   ss.str("");
   ss.clear();
 
-  JsonSection params;
   io::save<security::v2::Certificate>(selfSigned, ss);
   std::string selfSignedStr = ss.str();
-  params.add(ChallengeCredential::JSON_CREDENTIAL_SELF, selfSignedStr);
   ss.str("");
   ss.clear();
 
   io::save<security::v2::Certificate>(certB, ss);
   std::string credentialStr = ss.str();
-  params.add(ChallengeCredential::JSON_CREDENTIAL_CERT, credentialStr);
   ss.str("");
   ss.clear();
 
+  Block params = makeEmptyBlock(tlv_encrypted_payload);
+  params.push_back(makeStringBlock(tlv_parameter_key, ChallengeCredential::JSON_CREDENTIAL_SELF));
+  params.push_back(makeStringBlock(tlv_parameter_value, selfSignedStr));
+  params.push_back(makeStringBlock(tlv_parameter_key, ChallengeCredential::JSON_CREDENTIAL_CERT));
+  params.push_back(makeStringBlock(tlv_parameter_value, credentialStr));
+
   challenge.handleChallengeRequest(params, request);
   BOOST_CHECK_EQUAL(request.m_status, STATUS_PENDING);
   BOOST_CHECK_EQUAL(request.m_challengeStatus, CHALLENGE_STATUS_SUCCESS);
diff --git a/tests/unit-tests/challenge-email.t.cpp b/tests/unit-tests/challenge-email.t.cpp
index 398df97..834411d 100644
--- a/tests/unit-tests/challenge-email.t.cpp
+++ b/tests/unit-tests/challenge-email.t.cpp
@@ -48,11 +48,12 @@
   auto cert = key.getDefaultCertificate();
   CertificateRequest request(Name("/ndn/site1"), "123", STATUS_BEFORE_CHALLENGE, cert);
 
-  JsonSection emailJson;
-  emailJson.put(ChallengeEmail::JSON_EMAIL, "zhiyi@cs.ucla.edu");
+  Block paramTLV = makeEmptyBlock(tlv_encrypted_payload);
+  paramTLV.push_back(makeStringBlock(tlv_parameter_key, ChallengeEmail::JSON_EMAIL));
+  paramTLV.push_back(makeStringBlock(tlv_parameter_value, "zhiyi@cs.ucla.edu"));
 
   ChallengeEmail challenge("./tests/unit-tests/test-send-email.sh");
-  challenge.handleChallengeRequest(emailJson, request);
+  challenge.handleChallengeRequest(paramTLV, request);
 
   BOOST_CHECK_EQUAL(request.m_status, STATUS_CHALLENGE);
   BOOST_CHECK_EQUAL(request.m_challengeStatus, ChallengeEmail::NEED_CODE);
@@ -97,11 +98,12 @@
   auto cert = key.getDefaultCertificate();
   CertificateRequest request(Name("/ndn/site1"), "123", STATUS_BEFORE_CHALLENGE, cert);
 
-  JsonSection emailJson;
-  emailJson.put(ChallengeEmail::JSON_EMAIL, "zhiyi@cs");
+  Block paramTLV = makeEmptyBlock(tlv_encrypted_payload);
+  paramTLV.push_back(makeStringBlock(tlv_parameter_key, ChallengeEmail::JSON_EMAIL));
+  paramTLV.push_back(makeStringBlock(tlv_parameter_value, "zhiyi@cs"));
 
   ChallengeEmail challenge;
-  challenge.handleChallengeRequest(emailJson, request);
+  challenge.handleChallengeRequest(paramTLV, request);
 
   BOOST_CHECK_EQUAL(request.m_challengeStatus, ChallengeEmail::FAILURE_INVALID_EMAIL);
   BOOST_CHECK_EQUAL(request.m_status, STATUS_FAILURE);
@@ -117,11 +119,12 @@
   CertificateRequest request(Name("/ndn/site1"), "123", STATUS_CHALLENGE, ChallengeEmail::NEED_CODE,
                              "Email", time::toIsoString(time::system_clock::now()), 3600, 3, json, cert);
 
-  JsonSection requestJson;
-  requestJson.put(ChallengeEmail::JSON_CODE, "4567");
+  Block paramTLV = makeEmptyBlock(tlv_encrypted_payload);
+  paramTLV.push_back(makeStringBlock(tlv_parameter_key, ChallengeEmail::JSON_CODE));
+  paramTLV.push_back(makeStringBlock(tlv_parameter_value, "4567"));
 
   ChallengeEmail challenge;
-  challenge.handleChallengeRequest(requestJson, request);
+  challenge.handleChallengeRequest(paramTLV, request);
 
   BOOST_CHECK_EQUAL(request.m_challengeStatus, CHALLENGE_STATUS_SUCCESS);
   BOOST_CHECK_EQUAL(request.m_status, STATUS_PENDING);
@@ -138,11 +141,12 @@
   CertificateRequest request(Name("/ndn/site1"), "123", STATUS_CHALLENGE, ChallengeEmail::NEED_CODE,
                              "email", time::toIsoString(time::system_clock::now()), 3600, 3, json, cert);
 
-  JsonSection requestJson;
-  requestJson.put(ChallengeEmail::JSON_CODE, "7890");
+  Block paramTLV = makeEmptyBlock(tlv_encrypted_payload);
+  paramTLV.push_back(makeStringBlock(tlv_parameter_key, ChallengeEmail::JSON_CODE));
+  paramTLV.push_back(makeStringBlock(tlv_parameter_value, "7890"));
 
   ChallengeEmail challenge;
-  challenge.handleChallengeRequest(requestJson, request);
+  challenge.handleChallengeRequest(paramTLV, request);
 
   BOOST_CHECK_EQUAL(request.m_challengeStatus, ChallengeEmail::WRONG_CODE);
   BOOST_CHECK_EQUAL(request.m_status, STATUS_CHALLENGE);
diff --git a/tests/unit-tests/challenge-pin.t.cpp b/tests/unit-tests/challenge-pin.t.cpp
index adac6b9..81ee1e1 100644
--- a/tests/unit-tests/challenge-pin.t.cpp
+++ b/tests/unit-tests/challenge-pin.t.cpp
@@ -42,7 +42,7 @@
   CertificateRequest request(Name("/ndn/site1"), "123", STATUS_BEFORE_CHALLENGE, cert);
 
   ChallengePin challenge;
-  challenge.handleChallengeRequest(JsonSection(), request);
+  challenge.handleChallengeRequest(makeEmptyBlock(tlv_encrypted_payload), request);
 
   BOOST_CHECK_EQUAL(request.m_status, STATUS_CHALLENGE);
   BOOST_CHECK_EQUAL(request.m_challengeStatus, ChallengePin::NEED_CODE);
@@ -59,11 +59,12 @@
   CertificateRequest request(Name("/ndn/site1"), "123", STATUS_CHALLENGE, ChallengePin::NEED_CODE, "pin",
                              time::toIsoString(time::system_clock::now()), 3600, 3, secret, cert);
 
-  JsonSection paramJson;
-  paramJson.put(ChallengePin::JSON_PIN_CODE, "12345");
+  Block paramTLV = makeEmptyBlock(tlv_encrypted_payload);
+  paramTLV.push_back(makeStringBlock(tlv_parameter_key, ChallengePin::JSON_PIN_CODE));
+  paramTLV.push_back(makeStringBlock(tlv_parameter_value, "12345"));
 
   ChallengePin challenge;
-  challenge.handleChallengeRequest(paramJson, request);
+  challenge.handleChallengeRequest(paramTLV, request);
 
   BOOST_CHECK_EQUAL(request.m_status, STATUS_PENDING);
   BOOST_CHECK_EQUAL(request.m_challengeStatus, CHALLENGE_STATUS_SUCCESS);
@@ -80,11 +81,12 @@
   CertificateRequest request(Name("/ndn/site1"), "123", STATUS_CHALLENGE, ChallengePin::NEED_CODE, "pin",
                              time::toIsoString(time::system_clock::now()), 3600, 3, secret, cert);
 
-  JsonSection paramJson;
-  paramJson.put(ChallengePin::JSON_PIN_CODE, "45678");
+  Block paramTLV = makeEmptyBlock(tlv_encrypted_payload);
+  paramTLV.push_back(makeStringBlock(tlv_parameter_key, ChallengePin::JSON_PIN_CODE));
+  paramTLV.push_back(makeStringBlock(tlv_parameter_value, "45678"));
 
   ChallengePin challenge;
-  challenge.handleChallengeRequest(paramJson, request);
+  challenge.handleChallengeRequest(paramTLV, request);
 
   BOOST_CHECK_EQUAL(request.m_status, STATUS_CHALLENGE);
   BOOST_CHECK_EQUAL(request.m_challengeStatus, ChallengePin::WRONG_CODE);