Data masking is a security technique used to protect sensitive CRM data by replacing real information with fictional or anonymized values while maintaining its usability. This ensures that unauthorized users, such as software testers or third-party vendors, cannot access private customer details. For example, a CRM may mask credit card numbers in customer records, displaying only the last four digits while storing the full number securely. Data masking techniques include encryption, tokenization, and format-preserving masking. Many businesses use data masking to comply with privacy regulations like GDPR and PCI DSS, preventing unauthorized exposure of personally identifiable information (PII). By implementing data masking, organizations strengthen security, reduce data breach risks, and maintain customer trust.