diff --git a/src/ENCRYPTO_utils/parse_options.cpp b/src/ENCRYPTO_utils/parse_options.cpp
index 41db41e..7b7e7e6 100644
--- a/src/ENCRYPTO_utils/parse_options.cpp
+++ b/src/ENCRYPTO_utils/parse_options.cpp
@@ -26,7 +26,7 @@
  * @param str the string to tokenize
  * @param tokens the result vector of wire id
  */
-void tokenize_verilog(const std::string& str, std::vector<uint32_t>& tokens, const std::string& delimiters) {
+void tokenize_verilog(const std::string& str, std::vector<int>& tokens, const std::string& delimiters) {
 
 	tokens.clear();
 
@@ -38,7 +38,7 @@ void tokenize_verilog(const std::string& str, std::vector<uint32_t>& tokens, con
 
 	while (std::string::npos != pos || std::string::npos != lastPos) {
 		// Found a token, add it to the vector.
-		tokens.push_back(atoi(str.substr(lastPos, pos - lastPos).c_str()));
+		tokens.push_back(stoi(str.substr(lastPos, pos - lastPos)));
 		// Skip delimiters.  Note the "not_of"
 		lastPos = str.find_first_not_of(delimiters, pos);
 		// Find next "non-delimiter"
@@ -64,7 +64,7 @@ void tokenize(const std::string& str, std::vector<uint32_t>& tokens, const std::
 
 	while (std::string::npos != pos || std::string::npos != lastPos) {
 		// Found a token, add it to the vector.
-		tokens.push_back(atoi(str.substr(lastPos, pos - lastPos).c_str()));
+		tokens.push_back(stoi(str.substr(lastPos, pos - lastPos)));
 		// Skip delimiters.  Note the "not_of"
 		lastPos = str.find_first_not_of(delimiters, pos);
 		// Find next "non-delimiter"
diff --git a/src/ENCRYPTO_utils/parse_options.h b/src/ENCRYPTO_utils/parse_options.h
index 0c64a13..78ca28a 100644
--- a/src/ENCRYPTO_utils/parse_options.h
+++ b/src/ENCRYPTO_utils/parse_options.h
@@ -71,6 +71,6 @@ int32_t parse_options(int32_t* argcp, char*** argvp, parsing_ctx* options, uint3
 */
 void print_usage(std::string progname, parsing_ctx* options, uint32_t nops);
 void tokenize(const std::string& str, std::vector<uint32_t>& tokens, const std::string& delimiters = "| \t");
-void tokenize_verilog(const std::string& str, std::vector<uint32_t>& tokens, const std::string& delimiters = " \t");
+void tokenize_verilog(const std::string& str, std::vector<int>& tokens, const std::string& delimiters = " \t");
 
 #endif /* PARSE_OPTIONS_H_ */