constructuri and verifymessage skeleton

diff --git a/service/kv_service/c_validator.cpp b/service/kv_service/c_validator.cpp
index e2b0db8..92a596a 100644
--- a/service/kv_service/c_validator.cpp
+++ b/service/kv_service/c_validator.cpp

@@ -31,7 +31,8 @@
 }
 
 /* 
- * TODO: Use actual BER/DER decoding functions from a cryptographic library
+ * TODO: Use actual BER/DER decoding functions from a cryptographic library and
+ * replace hardcoded numbers with names of ASN1 bits
  *
  * Example string: pGSAIB4t58gi0CHneoXjs358ykJTwUWGZkWkBo7DLZV64c2KgUDoeWkz2-KrjDXh5ulHa2t-WiF5TT4RnBhqrcXJulJ135i_ipXmtJkLUrsGy884eRNb2_LE8RU2CMtRe4J-3IYM
  *
@@ -74,12 +75,29 @@
   return ptr;
 }
 
-void CValidator::ConstructURI() {
-  ;
+/*
+ * TODO: Follow the steps according to
+ * https://perfect-sunstone-a3b.notion.site/NexRes-C-validation-369f5ad4ef074a1684dc227702a5c866
+ */
+std::string CValidator::ConstructURI(std::string &public_key, std::string &signature) {
+  // TODO: DER encode the fingerprint content object 
+
+  // TODO: SHA256 hash the fingerprint content
+
+  // TODO: Generate the fingerprint from the hash
+  std::string fingerprint = "";
+
+  return "ni:///sha-256;" + fingerprint + "?fpt=" + "ed25519-sha-256" + 
+  "&cost=" + std::to_string(ED25519_CRYPTOGRAPHY_COST);
 }
 
-void CValidator::VerifyMessage() {
-  ;
+/*
+ * TODO: Follow the steps according to
+ * https://perfect-sunstone-a3b.notion.site/NexRes-C-validation-369f5ad4ef074a1684dc227702a5c866
+ */
+bool CValidator::VerifyMessage(std::string &public_key, std::string &signature,
+                              std::string &message) {
+  return true;
 }
 
 std::string CValidator::base64_add_padding(std::string data) {
@@ -96,6 +114,14 @@
   return encoded_data;
 }
 
+std::string CValidator::base64_remove_padding(std::string data) {
+  int i = data.length() - 1;
+  while (i >= 0 && data[i] == '=') {
+    i--;
+  }
+  return data.substr(0, i+1);
+}
+
 std::string CValidator::CreateMessage(std::string& tx) {
   rapidjson::Document doc;
   doc.Parse(tx);

diff --git a/service/kv_service/c_validator.h b/service/kv_service/c_validator.h
index bd4b806..60838e5 100644
--- a/service/kv_service/c_validator.h
+++ b/service/kv_service/c_validator.h

@@ -12,16 +12,19 @@
 
 class CValidator {
  public:
-  std::string CCFulfill(std::string& fulfillment);
-  std::unique_ptr<std::vector<std::string>> DERDecode(std::string& uri_bytes_str);
-  void ConstructURI();
-  void VerifyMessage();
-  std::string CreateMessage(std::string& tx);
-  void printHex(std::string& str);
+  std::string CCFulfill(std::string &fulfillment);
+  std::unique_ptr<std::vector<std::string>> DERDecode(std::string &uri_bytes_str);
+  std::string ConstructURI(std::string &public_key, std::string &signature);
+  bool VerifyMessage(std::string &public_key, std::string &signature,
+                    std::string &message);
+  std::string CreateMessage(std::string &tx);
+  void printHex(std::string &str);
  private:
   std::string base64_add_padding(std::string data);
-  std::string SerializeMessage(std::string& tx);
-  void RemoveSignature(rapidjson::Document& doc);
+  std::string base64_remove_padding(std::string data);
+  std::string SerializeMessage(std::string &tx);
+  void RemoveSignature(rapidjson::Document &doc);
   const int PUBLIC_KEY_LENGTH = 32;
   const int SIGNATURE_LENGTH = 64;
+  const int ED25519_CRYPTOGRAPHY_COST = 131072; // 2^17
 };
\ No newline at end of file

diff --git a/service/kv_service/c_validator_main.cpp b/service/kv_service/c_validator_main.cpp
index 82da5d3..609e37a 100644
--- a/service/kv_service/c_validator_main.cpp
+++ b/service/kv_service/c_validator_main.cpp

@@ -31,6 +31,8 @@
 
   cval.printHex(public_key);
 
+  cval.ConstructURI(public_key, signature);
+
 /*  // std::string tx = "{\"inputs\":[{\"owners_before\":[\"C1CECot9umaqYvCjpt31GiKpYmsaGWQDdnHJjCv8yQiS\"],\"fulfills\":{\"transaction_id\":\"123415ca19849d95571e0d828102365f24bd322a54d6701e477d32a5bd009c6f\",\"output_index\":0},\"fulfillment\":\"pGSAIKN9QFdMwU21tgN2hzUd8pi75C8EsQ6LjnMjLssTKgivgUAmOHl2O1vsWN_bvPjoofVWyHf1p_thSJIUNCkfNStc748Rz37tMPT8NouEgjIvwgXpM1zOvA3TmzdoCjpaNm0N\"}]}";
   
   std::string tx = "{ \"inputs\":[ { \"owners_before\":[ \"C1CECot9umaqYvCjpt31GiKpYmsaGWQDdnHJjCv8yQiS\" ], \"fulfills\":{ \"transaction_id\":\"123415ca19849d95571e0d828102365f24bd322a54d6701e477d32a5bd009c6f\", \"output_index\":0 }, \"fulfillment\":\"pGSAIKN9QFdMwU21tgN2hzUd8pi75C8EsQ6LjnMjLssTKgivgUAmOHl2O1vsWN_bvPjoofVWyHf1p_thSJIUNCkfNStc748Rz37tMPT8NouEgjIvwgXpM1zOvA3TmzdoCjpaNm0N\" } ], \"outputs\":[ { \"public_keys\":[ \"DeVmcDk2G9TDYUtuLsozEWs9eCNRfbgfxaCntdKYKxXE\" ], \"condition\":{ \"details\":{ \"type\":\"ed25519-sha-256\", \"public_key\":\"DeVmcDk2G9TDYUtuLsozEWs9eCNRfbgfxaCntdKYKxXE\" }, \"uri\":\"ni:///sha-256;koZKY5-hToyQh-71lMhRS4WdYKFyNagSXEeBKxbuZpM?fpt=ed25519-sha-256&cost=131072\" }, \"amount\":\"1\" } ], \"operation\":\"TRANSFER\", \"metadata\":null, \"asset\":{ \"id\":\"123415ca19849d95571e0d828102365f24bd322a54d6701e477d32a5bd009c6f\" }, \"version\":\"2.0\", \"id\":\"780b0c416519aac2137c143ed1929b8783c99df001d3660a4b29508fad58443b\" }";

diff --git a/service/kv_service/sdk_transaction.cpp b/service/kv_service/sdk_transaction.cpp
index ede3896..6b3d317 100644
--- a/service/kv_service/sdk_transaction.cpp
+++ b/service/kv_service/sdk_transaction.cpp

@@ -1,3 +1,9 @@
+/*
+ * WORK IN PROGRESS
+ * 
+ * To be used with libcryptoconditions for SDK transaction validation
+ */
+
 #include "sdk_transaction.h"
 
 #include <cryptopp/files.h>

diff --git a/service/kv_service/sdk_transaction.h b/service/kv_service/sdk_transaction.h
index ed0c8fe..1f15eb7 100644
--- a/service/kv_service/sdk_transaction.h
+++ b/service/kv_service/sdk_transaction.h

@@ -1,3 +1,9 @@
+/*
+ * WORK IN PROGRESS
+ * 
+ * To be used with libcryptoconditions for SDK transaction validation
+ */
+
 #pragma once
 
 #include <string>

diff --git a/service/kv_service/sdk_transaction_manager.cpp b/service/kv_service/sdk_transaction_manager.cpp
index c373a62..1e844ad 100644
--- a/service/kv_service/sdk_transaction_manager.cpp
+++ b/service/kv_service/sdk_transaction_manager.cpp

@@ -1,3 +1,10 @@
+/*
+ * WORK IN PROGRESS
+ * 
+ * To be used with libcryptoconditions for SDK transaction validation
+ */
+
+
 #include "sdk_transaction_manager.h"
 
 SDKTransactionManager::SDKTransactionManager() {

diff --git a/service/kv_service/sdk_transaction_manager.h b/service/kv_service/sdk_transaction_manager.h
index 05506e7..0bed773 100644
--- a/service/kv_service/sdk_transaction_manager.h
+++ b/service/kv_service/sdk_transaction_manager.h

@@ -1,3 +1,9 @@
+/*
+ * WORK IN PROGRESS
+ * 
+ * To be used with libcryptoconditions for SDK transaction validation
+ */
+
 #pragma once
 
 #include <unordered_map>