More than 52% of Britons aged 18-25 use the same password for their online accounts
More than 52% of Britons aged 18-25 are using the same password for lots of online services, suggests a survey by Cyber Aware.
By doing so they make it easy for hackers to hijack accounts, warned the UK government's Cyber Aware campaign.
The danger was acute because of the sensitive data people typically send via email and other accounts, it found.
About 79% of the 2,261 respondents of all ages said they had sent bank details or copies of passports and driving licences via messaging systems.
Bank statements, electronic copies of signatures and other important documents could all be sitting in lists of sent emails.
"You wouldn't leave your door open for a burglar, so why give criminals an open invitation to your personal information?"
Reusing a password helps cyber-thieves because they try to use login names and password combinations released in data breaches on many different online accounts to see if they get a hit.
On average, the survey found, people regularly used at least six other online accounts covering everything from social media to online shopping. Some said they had as many as 21 other accounts they logged into frequently.
The survey suggested that younger people were most likely to use their email password on other accounts. Across the whole sample of respondents 27% reported that they reused the key identifier that unlocked their email.
Omegle links random people for virtual video and text chats, and claims to be moderated - but has a reputation for unpredictable and shocking content.
Free training is being offered to individuals, groups and staff in Warwickshire to become cyber champions.