> For the complete documentation index, see [llms.txt](https://developer.magtek.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://developer.magtek.com/hardware/card-readers/mms-dyna-devices/dynaflex-ii-go/documents/developers-manuals/programmers-manual-commands/security.md).

# Security

This section of the DynaFlex II Go Programmer's Manual details the cryptographic and operational security features required for PCI compliance and secure transaction processing, including message authentication codes (MAC), DUKPT key management, data encryption/decryption methods, and mandatory device behaviors such as the 24‑hour automatic reset and the optional device lock feature.

### Subsection

<table data-card-size="large" data-view="cards"><thead><tr><th></th></tr></thead><tbody><tr><td><a href="https://developer.magtek.com/hardware/card-readers/mms-dyna-devices/emv-common-kernel/dynaflex-ii-go/documents/developers-manuals/programmers-manual-commands/security/about-message-authentication-codes-mac"><mark style="color:$primary;"><strong>About Message Authentication Codes ></strong></mark></a></td></tr><tr><td><a href="https://developer.magtek.com/hardware/card-readers/mms-dyna-devices/emv-common-kernel/dynaflex-ii-go/documents/developers-manuals/programmers-manual-commands/security/about-key-serial-numbers-ksns"><mark style="color:$primary;"><strong>About Key Serial Numbers ></strong></mark></a></td></tr><tr><td><a href="https://developer.magtek.com/hardware/card-readers/mms-dyna-devices/emv-common-kernel/dynaflex-ii-go/documents/developers-manuals/programmers-manual-commands/security/about-encryption-and-decryption"><mark style="color:$primary;"><strong>About Encryption and Decryption ></strong></mark></a></td></tr><tr><td><a href="https://developer.magtek.com/hardware/card-readers/mms-dyna-devices/emv-common-kernel/dynaflex-ii-go/documents/developers-manuals/programmers-manual-commands/security/how-to-determine-the-key"><mark style="color:$primary;"><strong>How to Determine the Key ></strong></mark></a></td></tr><tr><td><a href="https://developer.magtek.com/hardware/card-readers/mms-dyna-devices/emv-common-kernel/dynaflex-ii-go/documents/developers-manuals/programmers-manual-commands/security/how-to-decrypt-data"><mark style="color:$primary;"><strong>How to Decrypt Data ></strong></mark></a></td></tr><tr><td><a href="https://developer.magtek.com/hardware/card-readers/mms-dyna-devices/emv-common-kernel/dynaflex-ii-go/documents/developers-manuals/programmers-manual-commands/security/24-hour-automatic-reset-pci-requirement"><mark style="color:$primary;"><strong>24 Hour Automatic Reset PCI Requirement ></strong></mark> </a></td></tr><tr><td><a href="https://developer.magtek.com/hardware/card-readers/mms-dyna-devices/emv-common-kernel/dynaflex-ii-go/documents/developers-manuals/programmers-manual-commands/security/device-lock-feature"><mark style="color:$primary;"><strong>Device Lock Feature ></strong></mark></a></td></tr></tbody></table>

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