Cryptography comeback

In the eyes of 20-year-old Dawn Xu, a sophomore at a university in Chongqing, Morse code, which was created in the 18th century, is incredibly useful. Ever since she learned how to do it last year after seeing it used in several films Morse code has appeared in her traveling notes, diary entries and even in a birthday card to her friend.

"When I first started using Morse code, I felt like a hipster because many people didn't know about it," she said. "The more I started using it, the more I discovered it is a very special way of expressing yourself. I can send messages in Morse code to people I am very close to."

Spy and mystery movies like the recently-released Kingsman: The Secret Service (2015) and Oscar-winning The Imitation Game (2014), have sparked an increased interest in Morse code and other ways of encryption, said Liu Weiran, a PhD student at the School of Electronics and Information Engineering at Beihang University who specializes in public key cryptography.

Morse code is a way of transmitting information using a series of dots and dashes for each letter of the Roman alphabet. SOS is widely accepted as the international Morse code distress signal, which is signified by three dots, three dashes and three dots.

"Though it is an ancient way of encoding and has mostly been replaced by more advanced ways in modern times, this old language has been given a second life with a lot of interesting usages," Liu said. "If people want to deliver a message, but do not want to tell others about it directly, they could code it into a message."

Liu said he has answered many Net users' questions about how to decode a message in Morse code or other ways of encryption on Zhihu, a Chinese community-based Q&A website similar to Quora.

One way to use Morse code, Liu said, is to slyly confess your love to someone. Another way is to offer a challenge to a friend by encoding information. "It is very simple and everybody can use it with a chart of International Morse code letters and numbers," Liu said.

"In fact, the best function of Morse code is for a confession of love, but I regret that I have not had a chance to experience that," Xu said. "You can write 'I Love You' in Morse code and hide it in a present. It is more special and subtle after he or she decodes the message, rather than telling him or her directly."

Xu said that she did once send a birthday card to her friend in Morse code, which successfully made her friend happy. She also sometimes writes notes to friends in Morse code so that other classmates can't read them. Xu recalled that in 2013, she wrote down her thoughts in a visitors' book in Morse code so that she didn't have to let others know what she said about a trip to Ciqikou, an ancient town in Chongqing.

"Years later if I revisited that place, I could still [easily] find the coded messages I left," Xu said.

Aside from being used in daily life, Morse code allegedly has been recently used in extreme situations. In January, Japanese reports said that Japanese war journalist Kenjo Goto, a hostage killed by the Islamic State (IS) militant group, tried to send the message 'Do not save me' by blinking in Morse code in video footage, but these reports have not been officially confirmed, according to an article published on guancha.cn, a website featuring public opinion articles, on February 2.

"Besides blinking, you can use just whatever you can think of to send a message in Morse code, like knocking your fingers on a desk," Liu said.

As for the future development of Morse code, Liu said while this old-fashioned way of communicating can bring fun and surprise to your life, it's doubtful that it will make a comeback as a mainstream trend.