The Home Depot believes that a cyberattack earlier this year affected 56 million unique payment cards as part of the largest retail security breach in history.

The Atlanta-based home retailer, which has more than 2,000 stores nationwide, says it has now eliminated the malware behind the attacks that took place between April and September.

It said it has also completed a 'major' payment security project that provides enhanced encryption of customers' payment data in its U.S. stores.

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Breach: The retailer has said it has now eliminated malware from its U.S. and Canadian networks that affected 56 million unique payment cards between April and September (file picture)

In December, Target Corp. disclosed a massive data breach that was the second-largest in history, resulting in the theft of 40 million debit and credit card numbers and the potential exposure of personal information of up to 70 million shoppers.

WHAT IF YOUR CARD IS AT RISK AND HOW TO PROTECT YOURSELF According to the Federal Trade Commission, one of the only ways customers can see if you have been hit by the hack is by checking bank statements for irregularities. You can also initiate a credit freeze - also known as a security freeze - which limits the access you have to credit reports, meaning hackers have less of an opportunity to open accounts in your name. In response to the breach, Home Depot is offering a year's coverage through identity theft protection programs - AllClear ID and AllClear PRO. It says that service is free. In order to protect yourself in the future, experts have suggested signing up to annualcreditreport.com. The service allows individuals to check if there has been any fraudulent activity on the account on a yearly basis. There are also more simple methods such as using different passwords for different accounts and primarily using credit cards for transactions - because they have better identity protection. Advertisement

Home Depot is believed to have been hit by the same malicious software program that stole card account data from cash registers at Target.

Retailers, banks and card companies have responded to the breaches by speeding the adoption of microchips in U.S. credit and debit cards - a technology that helps makes transactions more secure.

The U.S. is one of the only countries in the world to still use magnetic strips - one of the least safe ways of making a transaction - ahead of chip-based methods of payment.

According to Krebs on Security, the hack focused on the self-service lanes at the stores.

A source close to the investigation told the site that an analysis revealed some of Home Depot's store registers had been infected with a new variant of 'BlackPOS' - also known as 'Kaptoxa'.

It is a strain of malware designed to siphon data from cards when they are swiped at infected point-of-sale systems running Microsoft Windows.

To try and combat this, Home Depot has announced that it plans to have chip-enabled checkout terminals at all of its U.S. stores by the end of this year.

The store has also confirmed its sales-growth estimates for the fiscal year and expects to earn $4.54 per share in fiscal 2014, up 2 cents from its prior guidance.

Home Depot CEO Frank Blake said in a statement: 'We apologize to our customers for the inconvenience and anxiety this has caused, and want to reassure them that they will not be liable for fraudulent charges.

'From the time this investigation began, our guiding principle has been to put our customers first, and we will continue to do so.'