Hello. Signal, the favorite chat app for spies and journalists, got an unusual kind of endorsement this week after U.S. national-security officials were revealed to be using Signal to share information about a pending U.S. military strike, and mistakenly included a journalist in the chat.

WSJ provides an explainer of what you need to know about Signal and the rules governing how federal officials communicate. Read it here. 

More news: 

• Trump’s strategy for Signal chat fallout
• Pentagon warns employees about Signal vulnerability
• OpenAI ups its bug bounty rewards
• Deefake detection startup raises $17.5 million
• And more

• Hackers linked to Russia have targeted the Signal messaging app by exploiting a vulnerability that can let attackers link devices and see material not intended for them, according to an alert the Pentagon issued to employees. (National Public Radio)

Bigger bounties: Bug hunters can now get up to $100,000 for finding the most serious vulnerabilities in OpenAI products, the company said. That's up from a prior top payout of $20,000. The raise is part of a security-improvement program that includes asking researchers for proposals for better patching and threat detection, among other ideas. (Security Week)

Alleged hacker helper: Edward Coristine, who is part of Elon Musk's DOGE operation, while in high school two years ago ran a networking company called DiamondCDN that hosted a hacking group, among other customers, according to security researchers and internet records. (Reuters)

Deepfake detection company GetReal raised $17.5 million in a Series A round led by Forgepoint Capital, which specializes in cybersecurity startups. GetReal plans to market products to governments and businesses. (TechCrunch)

The WSJ Pro Cybersecurity team is Deputy Editor Kim S. Nash (on X @knash99), reporter Angus Loten, reporter James Rundle and reporter Catherine Stupp (@catstupp). Follow us on X @WSJCyber. Reach the team by replying to any newsletter you receive or by emailing Kim at kim.nash@wsj.com.