How Can I Encrypt Account Data in Transit (PCI DSS Requirement 4)?

How Can I Encrypt Account Data in Transit (PCI DSS Requirement 4)?

Sensitive data is quite vulnerable when it’s transmitted over open networks, including the Internet, public or otherwise untrusted wireless networks, and cellular networks. The PCI Security Standards Council takes a very hard line on data in transit, requiring the use of trusted keys/certificates, secure transport protocols, and strong encryption. The council also assigns you the ongoing task of reviewing your security protocols to ensure that they conform to industry best practices for secure communications.

Blocking eavesdroppers

Many potential attackers are eavesdroppers who are trying to exploit known security weaknesses. The PCI DSS includes specific requirements and guidance on establishing connections to other systems:

  • Proceed only when you have trusted keys/certificates in place. You’re expected to validate these keys and/or certificates and to make sure that they haven’t expired.
  • Configure your systems to use only secure protocols, and don’t accept connection requests from systems using weaker protocols or inadequate encryption key lengths.
  • Implement strong PCI DSS encryption for authentication and transmission over wireless networks that transmit card-holder data or that are connected to the cardholder data environment.

Securing end-user messaging

Much of the PCI DSS focuses on protecting PANs. Requirement 4 sets forth some specific rules about transmitting PANs across open networks. As a result, technologies that your organization normally uses (such as end-user messaging technologies) may need to be adapted, replaced, or discontinued when cardholder data is being transmitted. The main constraints of Requirement 4 are as follows:

  • PANs must never be sent unprotected over commercial technologies such as email, instant-messaging, and chat applications.
  • Before using any of these end-user technologies, you must ensure that PANs have been rendered unreadable via strong cryptography.
  • If a third party requests a PAN, that third party must provide a tool or method to protect the PAN, or you must render the number unreadable before transmission.

When you encrypt cardholder data as part of your network communications process, you must define the appropriate security policies and operational procedures. In addition, you must make sure that the relevant documents are kept up to date, made available to, and followed by all relevant people in your organization.

Note: This material is drawn from PCI Compliance & Data Protection for DummiesThales Limited Edition, by Ian Hermon and Peter Spier.

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