Is Helium Network secure?

Could you please elaborate on the security features of the Helium Network? I'm curious to know how it ensures the safety of transactions and the integrity of its blockchain. What kind of encryption methods does it utilize? How does it prevent potential attacks like hacking or double-spending? Also, what measures does the network take to safeguard users' private information? I'm looking for a comprehensive understanding of its security measures to assess its reliability as a platform for cryptocurrency transactions.