Which requirement in PCI DSS pertains specifically to cardholder data encryption?

The requirement that specifically pertains to cardholder data encryption is Requirement 3. This requirement focuses on protecting stored cardholder data and includes specific guidelines on encryption and cryptographic keys. It emphasizes the importance of securely storing cardholder data using best practices such as strong encryption methods to mitigate the risk of data breaches and unauthorized access.

In the context of PCI DSS, encryption serves as a critical control mechanism to ensure that even if cardholder data is exposed, it cannot be utilized without the corresponding decryption keys. Requirement 3 outlines the policies and technologies that must be implemented to protect this sensitive information.

This understanding is central to the PCI DSS framework, as protecting cardholder data is one of the primary goals. While other requirements in PCI DSS address different aspects of information security, Requirement 3 has a clear focus on the measures necessary to safeguard stored cardholder data through encryption and other protective methods.