Framework № PCI DSS 4.0 от 01.03.2022

Requirement 3: Protect Stored Account Data 

Overview:
Protection methods such as encryption, truncation, masking, and hashing are critical components of account data protection. If an intruder circumvents other security controls and gains access to encrypted account data, the data is unreadable without the proper cryptographic keys and is unusable to that intruder. Other effective methods of protecting stored data should also be considered as potential risk-mitigation opportunities. For example, methods for minimizing risk include not storing account data unless necessary, truncating cardholder data if full PAN is not needed, and not sending unprotected PANs using end-user messaging technologies such as e-mail and instant messaging.
If account data is present in non-persistent memory (for example, RAM, volatile memory), encryption of account data is not required. However, proper controls must be in place to ensure that memory maintains a non-persistent state. Data should be removed from volatile memory once the business purpose (for example, the associated transaction) is complete. In the case that data storage becomes persistent, all applicable PCI DSS Requirements will apply including encryption of stored data. 
Requirement 3 applies to protection of stored account data unless specifically called out in an individual requirement. 

3.5 Primary account number (PAN) is secured wherever it is stored.