Customers who wait for Cyber Monday to go holiday shopping must be as wary as customers in brick-and-mortar stores and shopping malls, guarding sensitive personal information from Internet scams and hackers.

In the past year, one in four Americans were notified that their personally identifiable information -- such as passwords, credit card numbers and email addresses -- had been compromised, according to the National Cyber Security Alliance, or NCSA, and digital security company McAfee.

At the same time, more consumers are turning to the Internet for their holiday shopping to avoid the hassle of Black Friday, which marks the beginning of a season of long lines and crowded malls.

Online commerce
The number of Americans using their phones to shop and manage finances is on the rise. In the past six months:
» 33 percent have researched purchases on smartphones.
» 33 percent used mobile banking.
» 27 percent shopped.
» 25 percent made online payments.
» 7 percent made purchases on auction sites.
Source: National Cyber Security Alliance, McAfee

More than $68 billion will be spent on online retail this holiday season, up 15 percent from 2011, according to projections by Forrester Research Inc.

"Holiday shoppers can expect cybercriminals to be out in force this season," said Michael Kaiser, executive director of the NCSA. "Shoppers should be alert to scams and other attempts to lure them to provide personal and financial information that could lead to data loss or the infection of an Internet-connected service."

Shopping on a smartphone can be just as dangerous as purchasing gifts via a desktop or laptop computer, and most of those phones aren't prepared to handle the risk. Sixty-three percent of smartphone owners haven't installed security software on their phones to protect them from viruses or malware, according to an online safety study conducted by the NCSA and McAfee.

The time to be vigilant has already come, experts warn. A survey by Google of 1,500 holiday shoppers found that 54 percent would start shopping for Christmas and other holidays before the post-Thanksgiving shopping holiday.

Some online retailers began marking down prices well before Black Friday -- Amazon's digital Black Friday store has been open for weeks.

- Ben Giles