Authenticator: pbkd5(): Mark as const

authenticator.cpp

@@ -37,7 +37,7 @@ void Authenticator::incFailureCount(std::string ip)
 	fl.lastfail = time(nullptr);
 }
 
-std::vector<char> Authenticator::pbkdf5(std::string password, const std::vector<char> &salt)
+std::vector<char> Authenticator::pbkdf5(std::string password, const std::vector<char> &salt) const
 {
 	unsigned char hash[32];
 	const EVP_MD *sha256 = EVP_sha256();