The Central American country of El Salvador said it strengthened the security of its Bitcoin (CRYPTO: BTC) investments. What Happened: This week, the nation transferred $400 million in Bitcoin to a safer storage option known as a cold wallet. President Nayib Bukele took to the social platform X to share the news and described the move as establishing “our first #Bitcoin piggy bank.” A cold wallet is a form of cryptocurrency storage that is not connected to the internet, which reduces the risk of hacking. It is typically a physical device, like a USB drive or a specialized hardware wallet, that…