The US Secret Service protects presidents and their families. SAUL LOEB/AFP/Getty Images Secret Service code names are among the worst-kept secrets in Washington. Though they're intended for internal use, the monikers agents use to communicate about the first family's security quickly become public through government filings, leaks to news outlets, or when agents are overheard at public events. Since new technology has enabled security agents to monitor officials in various ways, the names aren't as top-secret anymore. The White House Communications Agency assigns each member of the first family a code name for Secret Service agents to use during their time in the White House . These names come from a list of agency-approved choices that either the president chooses from or agents pick. Other members of the family are then assigned names that share the same first letter. Sometimes, it's the same letter as the family's last name, but not always.…