What type of data does PIN blocks fall under?

PIN blocks are classified as Sensitive Authentication Data. This classification is due to the nature of PIN blocks, which contain the encrypted representation of a personal identification number (PIN) used for authenticating cardholders. The security and sensitivity of this data are heightened because it is directly involved in the authentication process when making transactions.

Sensitive Authentication Data is specifically defined by PCI DSS as data that includes any information required to authenticate or authorize a cardholder or transaction. This encompasses not just PIN blocks but also other forms of authentication data that are highly confidential.

Understanding the classification of PIN blocks is essential for compliance with PCI DSS, as it highlights the importance of safeguarding this type of sensitive information to protect against fraud and unauthorized access.