In the wake of the largest data breach in Australia's history, cyber security advocates are urging customers to be vigilant as the mass online shopping event Black Friday approaches.
From mailing lists to personalised advertisements and customer points programs, companies are asking Australians for more data than ever, but how can we protect ourselves while shopping online?
While the onus should be on companies to secure customers' personal data, there are ways the public can avoid activity that might put their data at risk, a University of Wollongong expert said.
University of Wollongong Associate Professor Shahriar Akter researches both data privacy and digital innovation, and he said customer marketing has increased significantly with the emergence of big data.

Businesses can track customers through the web, and Professor Akter said they are not looking after customer data as they should.
As cyber crime increases, Australians should avoid handing over data they don't need to, he said, and be especially wary if any company asks for "100 points of ID".
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As Black Friday sales on November 25, and the Christmas period approaches, Professor Akter urged customers to be wary of sponsored ads on Facebook, which are often scams, and to avoid paying with bank transfers.
For customers shopping online, look for the 'lock mark' next to the URL, which shows whether a website is secure and authentic at the payment page, he said.
Professor Akter and University of Wollongong colleague Dr Kumar Biswas have also compiled a list of tips to help Australians protect themselves from cyber attacks, and ensure they are not putting their data at risk:

Think, look closely before clicking
If an email or text message looks suspicious, be cautious about clicking on any links or attachments.
Some examples of suspicious emails or texts include messages that offer a substantial financial gift or voucher or super-discounted deals for valuable items.
Use stronger passwords, enable multi-factor authenticators and keep softwares updated
When creating a password, experts recommend using a longer password that is a combination of words, letters, and symbols that is at least 12 characters long.
For example, you could use a sentence that you can easily remember and include numbers and symbols to make it more secure.
Keep transaction notifications turned on with financial apps
Having notifications turned on for your financial apps can help you keep an eye on ongoing transactions in real-time.
If you see any unauthorised transactions, you can notify your financial institutions immediately.
Educate yourself to remain cyber vigilant
You should be aware of common methods of identity theft and online fraud, such as phishing emails and malware.
Don't share your personal information or financial or health details with anyone over the phone or via email unless you're sure the request is legitimate.

Rosie Bensley
Illawarra Mercury trainee journalist and newest recruit.
Illawarra Mercury trainee journalist and newest recruit.