Most people trust what they watch — but that won't always be the case.

Tech is being developed that will make it easy to create fake video footage of public figures or audio of their voice.

The developments aren't perfect yet, but they threaten to turbocharge "fake news" and boost hoaxes online.

In years to come, people will need to be far more skeptical about the media they see.

LONDON — Late last year, some WikiLeaks supporters were growing concerned: What had happened to Julian Assange?

The then-45-year-old founder of the anti-secrecy publisher was no stranger to controversy. Since 2012, he has sheltered in the Ecuadorian Embassy in Knightsbridge, London, following allegations of sexual assault. (He denies them and argues the case against him is politically motivated.) But the publication of leaked emails from Democratic Party officials in the run-up to the US presidential election saw Assange wield unprecedented influence while at the centre of a global media firestorm.

A definitely alive Assange, standing on the balcony of the Ecuadorian Embassy in London. PA Images After the election, though, suspicions were growing that something had happened to him. Worried supporters highlighted his lack of public appearances since October and produced exhaustive timelines detailing his activities and apparent "disappearance." They combined their efforts to solve the mystery on the Reddit community r/WhereIsAssange.

Video interviews and photos of Assange were closely scrutinised amid speculation that they might have been modified with computer-generated imagery — or faked entirely, as at least one YouTube analysis alleged.

"We need to look at the many glitches in that interview, and there were many for sure," one amateur sleuth wrote on Reddit. "Either terrible editing went on or CGI or whatever was just not fluid enough to make the grade. We need to understand why Assange's head looked like a cut and paste to his suit."

Another investigator took an alternative approach: "I plan on watching the interview totally sober, and then vaping a whole bunch of weed and re-watching. I find that I can spot CGI or irregularities incredibly easily when I am really high."

This is not normal behaviour. When watching newsreel, or a clip of an interview on Facebook, most people don't give much thought as to whether the footage is real. They don't closely scrutinise it for evidence of elaborate CGI forgery.

But these concerns may not be confined to the paranoid fringes of the internet forever.

CGI and artificial intelligence are developing at a rapid pace, and in the coming years it will become increasingly easy for hoaxsters and propagandists to create fake audio and video — creating the potential for unprecedented doubt over the authenticity of visual media.

"The output we see from these models ... are still crude and easily identified as forgeries, but it seems to be only a matter of refinement for them to become harder to discern as such," Francis Tseng, a copublisher of The New Inquiry who curates a project tracking how technology can distort reality, told Business Insider.

"So we'll see the quality go up, and like with other technologies, the costs will go down and the technology will become accessible to more people."

Early tech demos are a sign of what is to come

We're already living in an era of "fake news." US President Donald Trump frequently lashes out online at the "phony" news media. Hoax news outlets have been created by Macedonian teenagers to make a quick buck from ad revenue, their stories spreading easily through platforms like Facebook. Public trust in the professional news media has fallen to an all-time low.

But a string of tech demos and apps highlight how this problem seems likely to get much worse.

Earlier in July, University of Washington researchers made headlines when they used AI to produce a fake video of President Barack Obama speaking, built by analysing tens of hours of footage of his past speeches. In this demo, called "Synthesizing Obama," the fake Obama's lips were synched to audio from one of his speeches — but it could have come from anywhere.

In a similar demo from 2016, "Face2face," researchers were able to take existing video footage of high-profile political figures including George W. Bush, Vladimir Putin, and Trump and make their facial expressions mimic those of a human actor, all in real time.

Even your voice isn't safe. Voice-mimicking software called Lyrebird can take audio of someone speaking and use it to synthesise a digital version of that person's voice — something it showed off to disconcerting effect with demos of Hillary Clinton, Obama, and Trump promoting it. It's in development, and Adobe, the company behind Photoshop, is also developing similar tools under the name Project Voco.

And once you start to combine these technologies, things get really interesting — or worrying. Someone could synthesise a speech from Trump using Lyrebird and then make a fake version of him generated with "Synthesising Obama"-style software.

You could quite literally put words into the mouth of any public figure.

It could undermine trust in everything you watch

Developers of this technology are awake to the dangerous possibilities of this tech. "Making these kinds of video-manipulation tools widely available will have strong social implications," Justus Thies, who helped to develop Face2face, told Business Insider. "That is also the reason why we do not make our software or source code publically available."

Children with access to such a software could "lift cyberbullying to a whole new level," Thies said, adding, "You can also assume that the number of fake news will increase."

An image from a YouTube demo of "Synthesizing Obama." Supasorn Suwajanakorn/YouTube

Supasorn Suwajanakorn, a researcher on "Synthesising Obama," agrees that it could be used to produce fraudulent material — but argues it could also lead to more skepticism among ordinary people. "It could potentially be used to create fake videos when combined with technology that can generate a person-specific voice," he said. "On the other hand, if such tools are widespread and well-known, people can be more cautious about treating video as a strong evidence. People know Photoshop exists, and no one simply believes photos. This could happen with videos."

This was echoed by Yaroslav Goncharov, the CEO of the photo-editing app FaceApp. People will just have to learn to stop taking videos at face value, he argued. "If ordinary people can create such content themselves, I hope it will make people pay more attention to verifying any information they consume," he said. "Right now, a lot of heavily modified/fake content is produced and it goes under the radar."

US President Donald Trump. Thomson Reuters He added: "Before printers were available, people could assign much high credibility to printed materials than to handwritten ones. Now when most people have a printer at home, they won't believe in something just because it is printed."

There's a flip side to the fact that it will become easy to make photo-realistic fraudulent video: It will also cast some doubts on even legitimate footage. If a politician or celebrity is caught saying or doing something untoward, there will be an increasing chance that the person could dismiss the video as being fabricated.

In October, Trump's presidential campaign was rocked by the "Access Hollywood" tape — audio of his discussing groping women in vulgar terms. What if he could have semi-credibly claimed the entire thing was just an AI-powered forgery?

It's not all bad, however: Just think of the entertainment!

So should conscientious developers swear off this technology altogether? Not so fast — there are also numerous positive use cases, including entertainment and video gaming.

Face2face suggested its techniques could be used in postproduction in the film industry or for creating realistic avatars for gaming. In the announcement of "Synthesising Obama," it is suggested that it could be used to reduce bandwidth during video chats and teleconferencing. (Don't bother streaming video — just send audio and synthesise the visuals instead!) Products like Lyrebird and Project Voco could help people with speech disorders synthesise fluent and realistic speech on demand.

And Tseng of The New Inquiry also posits that the tech could be used to "foster a wide culture of DIY entertainment: people editing clips from movies but replacing the dialogue or other elements in scenes or entirely synthesizing new clips by emulating actors and actresses."

But, he warns, developers still have a responsibility to take political issues into account. "Software development as a profession has grown so rapidly through so many informal channels that there is not much of a professional culture of ethics to speak of," he said. "Other engineering professions have developed pretty robust ethical standards, and those hold up because engineers trained in those professions go through a limited number of formal channels which expose them to those ethics. The boon of programming education is its decentralization and wide accessibility, but this also means people often pick up the skills without the necessary ethical frameworks to accompany them."

He added: "Anyone involved in the development of technology, directly or indirectly, has a responsibility to consider these issues, outright refuse to implement problematic technologies, or subvert them in some way."

The entertainment industry, of course, has long used CGI for entertainment purposes — and it is acutely aware of what further developments could herald. The December film release "Star Wars: Rogue One" featured a surprise appearance from actor Peter Cushing.

It was a particularly surprising appearance because Cushing had been dead for 22 years. His image was reconstructed using CGI overlaid on a real actor.

Left: The real Peter Cushing. Right: A digital reconstruction, two decades after Cushing's death. Lucasfilm/Disney

It wasn't a perfect recreation, but the stunt grabbed headlines and spooked some celebrities. Reuters reported at the time that its release led to actors "scrambling to exert control over how their characters and images are portrayed in the hereafter," negotiating contracts on how their image may or may not be used even after they die.

In January, Lucasfilm even had to deny that it was planning to incorporate a CGI Carrie Fisher into the coming movie "Star Wars: The Last Jedi" amid rumours that the studio was planning to get around the actress' death in December by making a digital version of her.

It's time to start getting ready

It's undeniable that developments in the coming years will heighten challenges people will face in finding and responsibly sharing media. In trying to solve these new challenges, everyone — journalists, developers, tech platforms, and consumers — may have a role to play.

Technology already exists to cryptographically sign footage captured by a camera, so it can be verified when required. News outlets and organisations could perhaps one day "sign" their footage, so anyone can check its authenticity. No matter how convincing the fake, if it's not cryptographically fingerprinted, viewers would know something was wrong.

Face2face suggests its findings could be built upon to help "detect inconsistencies" in media and help identify fraudulent imagery.

Thies argued that big tech platforms like Facebook would have a duty to proactively police for fraudulent media.

"Social-media companies as well as the classical media companies have the responsibility to develop and setup fraud detection systems to prevent spreading / shearing of misinformation," he said.

And as Goncharov of FaceApp and others suggested, it may force consumers to be more skeptical and not take video and audio at face value — much as they wouldn't with a photo or screenshot today.

In January, Julian Assange read out a hash from the bitcoin blockchain (essentially a high-tech version of holding up today's newspaper) on a public livestream in a bid to prove he was still alive.

But a decade from now, if creating real-time imagery of people from scratch becomes trivial, such authentication may no longer be enough.