An encrypted messaging app that allows users to delete their texts automatically after just a few seconds has become a favored way of communicating among some San Francisco supervisors and their aides, raising questions about whether technological advances are subverting public-records laws.

The app, Telegram, was created by a Russian entrepreneur and claims to be 100 percent encrypted. It is one of several apps, including Snapchat, Wickr and Frankly, that offer self-destructing messages, . The apps delete messages from the phones of both the sender and the receiver, and they use technology that makes it impractical and sometimes impossible for law enforcement or other third parties to decode.

Several supervisors said San Francisco City Attorney Dennis Herrera gave them the OK to use Telegram before they joined — Herrera won’t comment on advice his office gives to supervisors. But some public records proponents say the apps present a serious threat to government accountability and should be prohibited except for personal use.

“There is nothing inherently illegal about Telegram or Snapchat, provided you are not having secret meetings on it,” said Matt Dorsey, spokesman for the city attorney. “It doesn’t matter whether I am creating a public record on Snapchat or Telegram or having secret meetings over CB radio or any obscure iteration of technology in the last 50 years — the law sets out what a public record is, and it doesn’t attach to the technology.”

Peter Scheer, executive director of the First Amendment Coalition, said that’s true. But, he added, self-deleting apps create risks to government accountability that merit changes to the law to restrict their use by public officials.

“If these tools of secrecy are freely available in government, they will be used particularly by the most powerful people to keep secret the most sensitive information,” Scheer said. “I am concerned they are being used for precisely the communications that are most important for the public to have access to.”

Five supervisors use Telegram: Jane Kim, Aaron Peskin, John Avalos, David Campos and Malia Cohen. At least nine supervisorial aides are also on Telegram. (It’s possible that there are more if they use different phone numbers.)

The default setting on Telegram is for regular, non-deleting texts. It also offers a secret chat that boasts end-to-end encryption and a self-destruct timer that deletes the messages from the phones of both the sender and the receiver. The secret messages can’t be forwarded and leave no trace on its servers, Telegram says.

Kim appears to be the first supervisor to have downloaded the app, and subsequently turned her progressive colleagues on to it. She said she downloaded Telegram in the fall, but before doing so asked for and received the city attorney’s approval to use it.

Questions over the app’s use arose in March when a top aide to Kim told the tech website the Information that one reason officials use Telegram is because it “self-destructs.”

Kim said this week that she has since made clear to her staff that no government business should be conducted using secret chats.

“Your best friend and your husband, that’s fine, but not for government work,” Kim said.

She emphasized that the secret chats can be used only for one-to-one messaging and can’t be used in group texts.

Avalos, who joined Telegram in December, said he liked the app because of the group messaging feature. “You can set up a subject and share messages under it. Kind of like email but more immediate,” he said — in a message sent over Telegram. He said he had never used the secret chat.

Peskin, who downloaded the app in February, said he mostly used it for campaign-related issues that are not subject to public records laws. He said one exception is when he and other supervisors communicated via Telegram during negotiations with the Municipal Transportation Agency about lowering towing fees.

“All of those records have been retained, and we are waiting to hear from the city attorney. In the meantime, I am not using Telegram for things related to city business,” Peskin said.

While Telegram has gained popularity with San Francisco politicians, it is only one of many new apps that promise security. Some claim military-grade encryption, while others, like Snapchat, offer less security but have the appeal of disappearing almost instantaneously. Others, like Telegram, claim to provide both.

Take Wickr, which was launched in 2012 by a former defense contractor. The app boasts military-grade encryption that lets users send texts, videos, photos and audio files that last as little as one second or as long as six days. As soon as the message is received, the countdown begins. While most phones retain deleted material on their hard drive, which can be retrieved using special software, Wickr writes over the deleted file with random data, making it inaccessible.

“The technology of mass secrecy is now becoming widely available,” Scheer said. “And that defeats all access laws. It defeats a search warrant. It defeats a court order, potentially. It defeats access under the public records act or FOIA (the Freedom of Information Act). It can defeat everything.”

Of course, some of the apps may make overblown claims about their efficacy. Snapchat, a self-deleting photo and video app, initially claimed that the photos and videos disappeared forever, but later admitted they could be recovered. Even so, someone would have to know exactly what they were looking for to access the deleted files.

Peter Keane, a member of the San Francisco Ethics Commission, said the California Public Records Act, signed into law in 1968, doesn’t reflect the times.

“New technology is developing so rapidly that the public records laws — they still seem to reflect the 19th century where you have a quill pen scratching something out,” he said. “There is a lot of catching up to be done.”

The state Supreme Court may soon offer some guidance. It has agreed to hear a case on whether emails and texts sent by public officials on private cell phones and email accounts are subject to the California Public Records Act.

But the reality is that even email is passe among many politicians. Herrera, the city attorney, doesn’t have a government email address. The supervisors largely communicate via text, both among themselves and to reporters. Former Mayor Willie Brown, now a San Francisco Chronicle columnist, reportedly said the “e” in email stands for “evidence.”

Self-deleting apps aside, there are always the old-school ways of circumventing public-records laws. Politicians can write notes to each other on a piece of paper and then burn them. Or they could just pick up the phone.

Asked about Telegram, Board of Supervisors President London Breed said she had never heard of it.

“Why didn’t nobody invite me to a secret chat?” Breed said. “If you need to tell somebody something or talk to somebody, just go talk to them. Why do you need to do a secretive app to talk to somebody? I don’t get it.”

She added, “I don’t use it. I don’t have any plans to use it. And I definitely don’t think it should be used for city business.”

But if it were, you might not ever know.

Emily Green is a San Francisco Chronicle staff writer. Email: egreen@sfchronicle.com

Twitter: @emilytgreen