As internet advocates, security analysts, and activists scan the horizon for policy implications of Donald Trump's forthcoming presidency, many are concerned about the future of America's surveillance apparatus.

Consider these tweets:

REMINDER: the US Government has been doing mass surveillance for years via the NSA, you were complacent, now Donald Trump has access to it. — Secular Talk (@KyleKulinski) November 10, 2016

If you didn't get it before, this is why the surveillance of NSA-scale must not exist. Because one day, people like Trump will control it. — Rob (@Fringenos) November 9, 2016

Trump will now have full access to the NSA surveillance data. Every text, email, phone call, website visited…all fodder for his libel suits — ben grosser (@bengrosser) November 9, 2016

Tweets like these reflect worries among many cybersecurity observers and progressive activists. Mr. Trump's campaign gave them plenty of pause, from his promises to ban Muslim immigration to his statement that "a lot of people would be willing to give up some privacy in order to have more safety."

Now that Trump has won, nervous hand-wringing has turned into practical consideration of whether journalists, activists, and ordinary Americans should lock down online communications. There's already a rush to sign up for email encryption services and a spike in downloads for Signal, a secure messaging tool.

"Eight years of George W. Bush followed by eight years of Obama have allowed Trump to inherit a powerful surveillance state," says Eva Galperin, global policy analyst for the digital advocacy group Electronic Frontier Foundation (EFF). "He is likely to turn that surveillance on American citizens, especially people of color, Muslims, and his political enemies."

That surveillance capacity could include tools similar to PRISM, a clandestine National Security Agency (NSA) program to collect and analyze private internet communications and phone records. After former NSA contractor Edward Snowden exposed details about PRISM and other surveillance practices, the US faced domestic and international backlash over its data collection programs. As a result, Congress passed the USA Freedom Act in 2015 that made modest adjustments to American surveillance powers.

And while the Obama administration came under fire from privacy advocates and politicians over the lengths that law enforcement can – or should – go to intercept and collect Americans' data, that debate largely remains unsettled.

That’s why the election is so concerning to Shauna Dillavou, founder of CommunityRed, a nonprofit that supports the digital security of activists and journalists to promote free speech around the world. Ms. Dillavou's organization works in a dozen countries helping people protect communications from authoritarian regimes. In the US, CommunityRed's work primarily focuses on protecting feminist and environmental activists.

"We know the capabilities of PRISM continue, and the data is kept forever," she says. "All the major commercial platforms [like Google, Facebook, and Twitter] now have a far greater possibility of handing over info to the federal government than there has ever been."

Benjamin Wittes, a Brookings Institution fellow and cofounder of the Lawfare blog, is less concerned about the prospect for NSA abuse. "The intelligence community, particularly the NSA, is much less amenable to abuse than people think it is," says Mr. Wittes. "Because it is operating under a really complex statutory scheme."

But that doesn't mean activists have nothing to worry about, according to Wittes. In a pre-election series on the Lawfare blog, he detailed some of the potential dangers of a Trump presidency.

"The civil liberties community is way too focused on the surveillance architecture," he says. "And not focused enough on the direct instruments by which certain types of repression occur, like prosecution and civil litigation."

Those mechanisms of repression may not even lie with the government itself.

"I think the bigger threat is the way [Trump] pits us against one another," says Dillavou of CommunityRed. "America has elected someone who normalizes hate and empowers bigotry ... . Demonstrations of bigotry are going to permeate social media."

For those feeling anxious after the election, tech experts say there are some simple measures that can help people exercise their political voice while insulating themselves from potential surveillance. For instance, the EFF maintains a Surveillance Self-Defense kit, which includes specific tips for activists.

"One of the ways you can protect the contents of communications from the kind of surveillance the NSA does, and which we fear may be given over the hands of the FBI, is using end-to-end encrypted communications," Ms. Galperin says. For encrypted text messaging, she recommends such encrypted chat apps as Signal.

Dillavou suggests that activists who travel in and out of the US take steps to secure their computers and other digital devices. For example, she said, before arriving at the security line, "make sure your computer is off, that you have full-disk encryption on, and that it needs a password. They can ask you to turn it on, but can't compel you to enter your password."

She also recommends activists disconnect their cellphones from as many accounts as possible when traveling, and use a separate email address that only has recent messages – so that potential spies can't get access to your entire email history.

These are some of the steps that activists have long taken in countries where surveillance is more widespread. Journalists or dissidents in Russia, China, or Saudi Arabia, for instance, are all too familiar with guarding their activities or sources from eavesdropping government agents or police.

"One of the things we see over and over [in other countries] is that people who stick their necks out too far are the people who [are victims of cyberattacks], whose funders get approached and told they have to register in this country if they want to continue funding, who get visits from government officials," says Dillavou of CommunityRed.

But in a new era of online vitriol, she says anyone who thinks about expressing an opinion on the web should take precautions.

She recommends that concerned internet users conduct a "personal audit of what's out there about you. Look to see what's out there about you by googling your name ... . Look at what's there online. Do everything in your power to hide your physical address. Make sure that location services don’t show your habits – for example, don’t save your home address on your Google maps app."

While it's unknown if there will be an uptick in surveillance activities under Mr. Trump's administration, many internet users are readying themselves for that possibility. If anything, Trump could be the president who finally gets Americans to protect their own digital privacy.