diff --git a/generator.cpp b/generator.cpp
index 5f1770a..70fa51d 100644
--- a/generator.cpp
+++ b/generator.cpp
@@ -92,11 +92,11 @@ auto Generator::do_crypto() -> std::string {
 	// https://www.cryptopp.com/wiki/CTR_Mode
 
 	// William Shakespeare, Romeo and Juliet
-	std::string plain{"Oh, I am fortune's fool!"};
+	const std::string plain{"Oh, I am fortune's fool!"};
 	std::string cipher, encoded_c;
 	std::unique_lock<std::mutex> ul(crypt_mtx);
 	// in case we need to convert counter to string
-	std::string str_ctr{reinterpret_cast<const char*>(&G.ctr)};
+	const std::string str_ctr{reinterpret_cast<const char*>(&G.ctr)};
 	// 16 bytes --> 128bit
 	static constexpr const std::size_t ctr_length{16};
 	CryptoPP::FixedSizeSecBlock<CryptoPP::byte, ctr_length> ctr;