After hearing that 2 million PSN user’s credit card information could be going up for auction around hacking groups, Sony has responded on the Official PlayStation Blog to the revelation that credit information was compromised by detailing a bit more about how credit card numbers are stored. Apparently, Sony stores credit card numbers after they have been altered by a cryptographic hash function.

From the Official Post

One other point to clarify is from this weekend’s press conference. While the passwords that were stored were not “encrypted,” they were transformed using a cryptographic hash function. There is a difference between these two types of security measures which is why we said the passwords had not been encrypted. But I want to be very clear that the passwords were not stored in our database in cleartext form. For a description of the difference between encryption and hashing, follow this link.

To reiterate a few other security measures for your information: Sony will not contact you in any way, including by email, asking for your credit card number, social security number or other personally identifiable information. If you are asked for this information, you can be confident Sony is not the entity asking. When the PlayStation Network and Qriocity services are fully restored, we strongly recommend that you log on and change your password. Additionally, if you use your PlayStation Network or Qriocity user name or password for other unrelated services or accounts, we strongly recommend that you change them, as well. To protect against possible identity theft or other financial loss, we encourage you to remain vigilant, to review your account statements and to monitor your credit reports.